What hydraulic engineering. Hydraulic structures: what is it, general standards for design and calculation

Hydraulic structures

buildings intended for use water resources(rivers, lakes, seas, groundwater) or to combat the destructive effect of the water element. Depending on G.'s location with. can be sea, river, lake, pond. Distinguish also ground and underground G. of page. In accordance with the serviced branches of the water economy G. s. There are: water power, reclamation, water transport, timber rafting, fisheries, for water supply and sewerage, for the use of water resources, for the improvement of cities, for sports purposes, etc.

Distinguish G. with. general, used for almost all types of water use, and special, built for any one branch of the water management. To the general G. of page. include: water-retaining, water supply, regulatory, water intake and spillway. Water retaining structures create a pressure or difference in water levels in front of the structure and behind it. These include: dams (the most important and most common type of hydroelectric dam) that block river channels and river valleys that raise the level of water accumulated in the upstream; fencing off the coastal territory and preventing its flooding during floods and floods on rivers, during tides and storms on the seas and lakes.

Water supply structures (water conduits) serve to transfer water to specified points: canals, hydrotechnical tunnels (See Hydrotechnical tunnel), flumes (See Tray), Pipelines. Some of them, such as channels, due to natural conditions their location, the need to cross communication routes, and ensuring the safety of operation require the construction of other G. with., United in a special group of structures on canals (Aqueduct and, Dyukery, bridges, ferry crossings, barriers, gates, Spillway, Shugosbros, etc.). ).

Regulatory (corrective) G. with. designed to change and improve natural conditions flow of watercourses and protection of river channels and banks from erosion, sedimentation, ice impact, etc. When regulating rivers, jet guides (semi-dams), shields, dams, etc., bank protection structures, ice guides and ice retention structures are used.

Water intake (water intake) structures are arranged to take water from a water source and direct it to a water conduit. In addition to ensuring an uninterrupted supply of water to consumers in the right amount and at the right time, they protect water supply facilities from the ingress of ice, sludge, sediment, etc.

Discharge structures are used to pass excess water from reservoirs, canals, pressure basins, etc. They can be channel and coastal, surface and deep, allowing partial or complete emptying of reservoirs. To regulate the amount of released (discharged) water, spillways supply hydraulic gates(See Hydraulic seal). In case of small water discharges, automatic spillways are also used, which automatically turn on when the level of the upper Beef rises above a predetermined level. These include open weirs (without gates), spillways with automatic gates, siphon spillways.

Special G. with. - structures for the use of water energy - buildings of hydroelectric stations (see hydroelectric station), penstocks, etc.; water transport structures - navigable Locks, Ship lift and, Lighthouse and, etc.. structures according to the situation of the ship's passage, boats, log launches, etc.; port facilities - Moles, Breakwaters, Piers, moorings, Docks, Ellings, Slips, etc.; ameliorative - main and distribution canals, sluice-regulators on irrigation and drainage systems; fisheries - fish passages, fish elevators, fish ponds, etc.

In a number of cases, general and special structures are combined in one complex, for example, a spillway and a hydroelectric power station building (the so-called combined hydroelectric power station) or other structures to perform several functions simultaneously. In the implementation of water management measures, G. s., United by a common goal and located in one place, make up complexes called units of G. s. or waterworks (See Waterworks). Several hydro units form water management systems, for example, energy, transport, irrigation, etc.

In accordance with their importance for the national economy of G. with. (objects of hydrotechnical construction) in the USSR are divided by capital into 5 classes. The main constants of G. of page belong to the 1st class. hydroelectric power plants with a capacity of more than 1 million kw; to the 2nd - the construction of hydroelectric power plants with a capacity of 301 thousand - 1 million cubic meters. kW, structures on super-main inland waterways (for example, on the Volga River, the Volga-Don Canal named after V. I. Lenin, etc.) and structures of river ports with a navigational cargo turnover of more than 3 million conventional t; to the 3rd and 4th classes - construction of hydroelectric power plants with a capacity of 300 thousand tons. kW and less, structures on main inland waterways and local routes, structures of river ports with a cargo turnover of 3 million conditional t and less. Temporary G. of page belong to the 5th class. Land reclamation construction objects are also divided into 5 classes according to capital size. Depending on the class in the projects, the degree of reliability of the gas pumping station is assigned, that is, the margins of their strength and stability, the estimated maximum water consumption, the quality of building materials, etc. are established. In addition, according to the capital class of G. s. the volume and composition of survey, design and research work is determined.

Characteristic features of G. of page. are connected with impact on G. of page. water flow, ice, sediment and other factors. This impact can be mechanical (static and hydrodynamic loads, soil suffusion, etc.), physicochemical (abrasion of surfaces, corrosion of metals, leaching of concrete), biological (rotting of wooden structures, wear of wood by living organisms, etc.). Conditions for the construction of G. s. are complicated by the need to pass through the structures during their construction (usually for several years), the so-called. construction costs of the river, ice, rafted timber, ships, etc. For the construction of G. with. extensive mechanization required construction works. Predominantly monolithic and prefabricated monolithic structures are used, less often prefabricated and typical, which is due to various non-repeating combinations of natural conditions - topographic, geological, hydrological and hydrogeological. The influence of hydrogeological systems, especially water-retaining ones, extends over a vast territory, within which certain areas of land are flooded, the level of groundwater rises, banks collapse, and so on. Therefore, the construction of such facilities requires high quality work and high reliability of structures, because. G.'s accidents with. cause serious consequences - human casualties and losses material assets(for example, the accidents of the Malpasse dam in France and the Vayont reservoir in Italy led to loss of life, destruction of cities, bridges and industrial structures).

G.'s improvement with. associated with the further development of hydraulic engineering (See Hydraulic engineering), especially theoretical and experimental studies of the effect of water on structures and their foundations (hydraulics of flows and structures, filtration), with the study of the behavior of rocky and non-rocky soils as a foundation and as a material for structures (Soil mechanics, Engineering geology) with the development of new types and designs of G. s. (lightweight high-pressure dams, tidal hydropower plants, etc.), requiring less time and money for their construction.

V. N. Pospelov.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

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The use of water resources has always been one of the basic conditions for maintaining human life. The need for them is determined not only by drinking needs, but also by economic, and nowadays more and more often by industrial tasks. Regulation of the use of water sources is provided by hydraulic structures that have different forms and functional content.

General information about hydraulic engineering

In a general sense, a hydrotechnical object can be represented as any functional structure or structure that interacts with water in one way or another. These can be not only man-made engineering systems, but also natural regulators, originally created by nature, but later exploited by people. What tasks are performed by modern objects of hydraulic structures? The main ones can be represented as follows:

• Structures intended for the use of water resources. As a rule, these are objects with water supply communications and equipment.
• Water protection facilities. Complexes, in the infrastructure of which several tasks can be performed. The most common for such objects are restrictions on the use and impact on the hydrological environment in order to prevent harmful effects on it.
• Industrial buildings. Engineering systems in which water circulation can be used as a source of energy.

Of course, this is only a part of the functions that hydraulic engineering performs. It rarely happens when one or two tasks are assigned to such structures. Usually large complexes support several workflows at once, including environmental, protective, regulatory, etc.

Main and secondary structures of hydraulic engineering

To begin with, it is worth determining the basic classification, in which there are permanent types of hydraulic structures, and temporary ones. According to the regulations, the first group includes the main and secondary objects. With regard to the main structures, they are understood as technical infrastructure, the destruction or damage of which can lead to the cessation of the normal functioning of the economy serviced by hydro resources. This may be a shutdown of the water supply of the irrigation system, the cessation of power plants, a reduction in shipping, etc. It is important to consider that the energy of hydrological turbines can serve entire enterprises (marine, ship repair, heating). Accordingly, stopping the water supply will disrupt the performance of such facilities.

The category of secondary structures includes hydraulic engineering, the destruction or damage of which will not entail the above consequences. For example, if the main hydraulic structures supply enterprises with production resources, then the secondary ones can participate in the regulation of this process without significantly affecting the result.

It is also worth mentioning the features of temporary structures that are used during periods of repair activities. If a depressurization occurred at the same main water supply facility, for example, then the maintenance team with the designer will have to create technical conditions to eliminate the problem. The solution to this problem can be the organization of the work of a temporary hydroelectric complex.

Classification by the way of interaction with the resource

The same task can be performed different ways. As already noted, one complex is able to support several functional processes, but it is the conditions of interaction with a reservoir or drain that fundamentally differ and, accordingly, the nature of the performance of a particular function. According to these features, the following structures are distinguished:

• Water-retaining. Designed for blocking a watercourse, fencing a reservoir or a pond due to the adoption of water pressure. When assessing the watercourse, the level is noted above the water station (upstream), and below - downstream. The difference between these levels is called the pressure on the hydrological structure.
• Multifunctional ameliorative stations. These can be outlets, locks, dams and water separators. Within this group, a classification of hydraulic structures is also provided, according to which interface and blocking complexes are distinguished.
• Plumbing. Usually a network infrastructure formed by channels, tunnels, pipelines, water trays. Their task is simple - the delivery of a resource from the collection point to the reservoir or the final place of water use.
• Water intake. They collect a resource from the same drives for transportation to consumers.
• Spillway. Unlike intake structures, such stations only remove excess water. These objects include deep spillways, drain channels, water outlets, etc.
• Regulatory. They control the interaction of the flow with the channel, preventing the exit of water beyond the fence, erosion and sedimentation.

Dangerous hydraulic facilities

This group of structures may include representatives of all hydraulic facilities, regardless of purpose. A dangerous station can be due to a high risk of an accident, an ownerless state, being in a risk zone due to the influence of third-party factors, etc. Lists with dangerous objects are formed by specialists from the Ministry of Emergency Situations and employees of Rosprirodnadzor. For each region, a comprehensive audit is carried out with the identification of objects that pose a threat. Dangerous hydraulic structures are recognized after the following procedures have been performed:

• The morphometric characteristics of the object are identified and specified.
• The technical condition of the structure and the degree of its safety are determined.
• The potential amount of damage that may occur in the event of an accident (for example, after the destruction of the dam body) is determined.
• Zoning of the area around the object is being carried out with an area that will depend on the degree of risk and threat from a particular structure.

After the object is recognized as dangerous, its observation is organized, and a schedule is drawn up for maintenance, technical repair and restoration work aimed at eliminating or minimizing the threat.

General and special hydraulic facilities

General facilities are understood as the majority of hydraulic engineering facilities related to regulatory, water supply, water intake and spillway stations. They are united by a single principle of performing their functions, which technologically can be imposed on different conditions operation.

In turn, special hydraulic engineering objects are designed for use in narrow areas where it is necessary to take into account the specifics of the equipment application. This applies to design nuances, construction requirements, as well as direct operation of hydraulic structures. Examples of such objects are well demonstrated by the infrastructure of water transport:

• Shipping locks.
• Facilities for the maintenance of marine equipment.
• Ships and moorings.
• Lesospuski.
• Ship lifts.
• Ellings.
• Docks.
• Wave breakers, etc.

In the fish industry, fish ponds, fish elevators and fish passes are used. In the social and entertainment infrastructure, these can be water parks with swimming pools and aquariums. In each case, service activities will have their own specifics, which are taken into account even at the stage of project development. However, the terms of reference for the construction of hydraulic engineering should be considered separately.

Design of hydraulic facilities

The design documentation includes technical calculations of structures, characteristics of the equipment used, as well as the results of field observations of the operating conditions of the future structure for the timely detection of adverse processes and the appearance of possible defects. The environment must be comprehensively and comprehensively assessed in order to foresee and possibly prevent the threat of accidents from the outset.

In particular, the project for a hydraulic structure includes the following data:

• List of diagnostic and manageable indicators of the object and its bases, including security criteria.
• List of controlled actions and loads on structures from the environment.
• Composition of visual and instrumental observations.
• Results and operating conditions of control and measuring equipment.
• Technical and structural solutions and a block diagram of the state of the elements of the object, as well as information with predicting the behavior of the structure when interacting with man-made and natural factors.

Special attention is paid to safety criteria, on the basis of which decisions are also made on the use of equipment with certain characteristics. In addition, the main types of hydraulic structures for permanent operation are supplemented by emergency action projects. This documentation, in particular, describes measures aimed at preventing emergencies.

Security requirements

From the moment of design development and throughout the entire period of operation, the safety of a hydraulic facility is ensured on the basis of the requirements of the relevant declaration. This is the main document that indicates the risks, threats and operational nuances that must be considered by the maintenance personnel. The main requirements for the safety of hydraulic structures include the following:

• Maintaining an acceptable degree of risk of accidents.
• Regular diagnostics of structures and equipment with subsequent adjustments to the safety declaration.
• Ensuring the continuity of operation of the facility.
• Maintenance of measures for the organization of means of protection and technical control of structures.
• Monitoring of potential threats to the object.

Construction of hydraulic structures

First of all, the means of production of construction work are determined. The question of the degree of mechanization of the process is fundamental, since in most cases the implementation of hydrotechnical station projects is carried out with the support of special equipment. At the very first stages of construction, earthworks are carried out with bulldozers, dump trucks, loaders and excavators, which allow you to quickly equip trenches, pits, wells and simply clear the work site.

In some cases, soil compaction is performed. For example, when creating reservoirs with a soil bowl. Similar operations are carried out in layers on the cleared soil with the help of special rollers. On smaller sites, diesel or petrol rammers can be used. However, experts still recommend abandoning hand tools in favor of mechanics. The recommendation is connected not so much with the acceleration of the pace of the workflow, but with the quality of the result. And this is especially true for the construction of hydraulic structures at the main stage of the construction of the structure. Concrete work requires high-quality reinforcement with strapping, the use of instructional materials and the addition of water-resistant plasticizers.

At the final stage, the engineering arrangement of the structure is carried out. Functional units, technical devices are installed and communications are laid. If we are talking about an autonomous station, then non-volatile generators are used, which will also require appropriate containment conditions in the infrastructure of the complex.

Operation of hydraulic engineering

The main activity of the service personnel is related to maintaining the optimal level of the technical condition of the facility, as well as monitoring its main functions. As for the first operational part, it comes down to the tasks of updating consumables, diagnosing equipment, communications, etc. In particular, operators check the technical condition of power supply networks, units and the integrity of structural materials. In case of detection of serious malfunctions or damages, the rules for the operation of hydraulic structures require the preparation of a separate project for repair and restoration measures, taking into account the available material reserves.

The second part of operational tasks focuses on control functions. Using automation, communication and telemechanics, another team of operators regulates the operation of the structure and its functional blocks, relying on control operations in accordance with standard parameters with allowable loads.

Reconstruction of hydraulic structures

The processes of obsolescence of structures and increasing requirements for the functional and power potential of the object inevitably lead to the need for modernization. As a rule, the main working modules and units are subject to reconstruction without stopping their work. However, this will depend on the nature of the planned changes. In each case, a survey of hydraulic structures is carried out for the possibility of reconstruction. The ultimate goals may be to increase the reliability of the foundation of the facility, increase the throughput, increase the capacity of pumping equipment, etc. After that, specific operations are implemented related to changes in the technical and operational properties of the structure. The tasks are achieved by strengthening the soil, replacing building materials and adding new structural elements.

Hydraulic engineering and environmental protection

Even at the design stage, together with the safety declaration, a report is drawn up on the measures that, during operation, will have to lead to an improvement in the environmental situation. Initially, the situation in the natural environment is assessed, and in the future, the developers make a comprehensive adjustment to maintain the protection of natural objects after the project has been implemented. In particular, biotechnical measures are being developed aimed at protecting the population from accidents at hydraulic structures and creating conditions for neutralizing negative operational factors.

Particular attention is paid to the impact of building structures and equipment on hydrological resources. For example, in reservoirs, special beds are prepared for the storage or disposal of liquid waste. Each facility also contains technical means to eliminate sources of chemical hazardous or simply dirty substances. For continuous monitoring of the environmental background, the infrastructure of hydraulic structures is supplemented with measuring instruments that record the biological and chemical indicators of water and air environments. The main characteristics of this kind include color, oxygen saturation, concentration of certain elements, sanitary indicators, etc.

Conclusion

The high responsibility of hydrological facilities is determined by the breadth of their areas of application and the significance of the tasks they solve. As a rule, hydraulic structures act only as a link in the working chain of large production and economic cycles. But the ultimate goals that are achieved with the support of such objects can be extremely important. For example, energy, land reclamation, transport, water supply are just some of the areas in which water resources are used.

Article 4 federal law"On the safety of hydraulic structures" Government Russian Federation decides:

1. Establish that hydraulic structures are divided into the following classes:

I class - hydraulic structures of extremely high danger;

Class II - high-risk hydraulic structures;

III class - hydraulic structures of medium danger;

Class IV - hydraulic structures of low danger.

2. Approve the attached criteria for the classification of hydraulic structures.

3. Establish that if a hydraulic structure, in accordance with the criteria approved by this resolution, can be assigned to different classes, such a hydraulic structure belongs to the highest of them.

Criteria for the classification of hydraulic structures
(approved by Decree of the Government of the Russian Federation of November 2, 2013 No. 986)

1. Classes of hydraulic structures depending on their height and type of foundation soil:

Notes: 1. Soils are divided into: A - rock; B - sandy, coarse-grained and clayey in solid and semi-solid state; B - clay water-saturated in a plastic state.

2. The height of a hydraulic structure and the assessment of its foundation are determined according to the design documentation.

3. In positions 4 and 7, instead of the height of the hydraulic structure, the depth of the base of the hydraulic structure is taken.

2. Classes of hydraulic structures depending on their purpose and operating conditions:

Notes: 1. The class of hydraulic structures of hydraulic and thermal power plants with an installed capacity of less than 1000 MW, indicated in position 2, is increased by one if the power plants are isolated from energy systems.

2. The class of hydraulic structures indicated in position 6 is increased by one for canals transporting water to arid regions in conditions of difficult mountainous terrain.

3. The class of hydraulic structures of the canal section from the head water intake to the first regulating reservoir, as well as the canal sections between the regulating reservoirs, provided for in position 6, is reduced by one if the water supply to the main water consumer during the period of liquidation of the consequences of an accident on the canal can be provided at the expense of the regulating reservoirs or other sources.

4. The class of hydraulic structures of river ports indicated in position 10 is increased by one if damage to the hydraulic structures of river ports can lead to emergencies of a federal, interregional and regional nature.

5. The class of hydraulic structures indicated in positions 13 and 14 is increased by one, depending on the complexity of ships under construction or repair.

6. The class of hydraulic structures specified in position 16 is increased by one if damage to such hydraulic structures can lead to an emergency.

7. The class of hydraulic structures indicated in position 17 is increased by one if damage to bank-protecting hydraulic structures can lead to emergencies of a federal, interregional and regional nature.

3. Classes of protective hydraulic structures, depending on the maximum pressure on the water-retaining structure:

4. Classes of hydraulic structures depending on the consequences of possible hydrodynamic accidents:

Document overview

Criteria for the classification of hydraulic structures have been established.

4 classes of their danger are allocated: I class - constructions of extremely high danger; II class - high danger; III class - medium danger; Class IV - hydraulic structures of low danger.

The classification is made depending on the height of hydraulic structures and the type of soil of their bases, the purpose and operating conditions, the maximum pressure on the water-retaining structures and the consequences of possible hydrodynamic accidents.

If a hydraulic structure can be attributed to different classes, it is assigned the highest of them.

Note that taking into account the class, measures are determined to ensure the safety of a hydraulic structure.

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1. General Provisions

The branch of science and technology, which, through the development of special complexes of structures, equipment and devices, is engaged in the use of water resources and combats their harmful effects, is called hydraulic engineering.

In hydraulic engineering, the following main branches of its application were determined:

the use of water energy, in which the energy of moving (falling) water is converted into mechanical, and then into electrical;

land reclamation (improvement) of lands by irrigation (irrigation) of dry areas and drainage of wetlands, as well as by protection from the harmful effects of water (flooding, waterlogging, erosion, etc.);

water transport - improvement of navigable conditions of rivers and lakes, construction of ports, locks, canals, etc.;

water supply and sewerage of populated areas and industrial enterprises.

All of the listed branches of hydraulic engineering are not isolated, but are closely related and intertwined with each other. complete solution water management problems.

According to their purpose, hydraulic structures are divided into general and special. The first, used in all branches of hydraulic engineering, include: water-lifting structures that create pressure and maintain it - dams, dams, etc.; culverts serving for useful water intake or discharge of excess water; water-carrying - channels, trays, pipelines and tunnels; regulatory - to regulate channels, protect banks from erosion, etc.; conjugating, serving for conjugation of pools and various hydraulic structures - drops, fast currents, abutments, separate bulls; ice- and slush-discharging and nano-removing. Special hydraulic structures used only under certain conditions include: hydropower - machine buildings of hydroelectric power stations, diversion structures; water transport - locks, canals, port facilities; hydroreclamation - water intakes, conduits, treatment facilities.

Hydraulic structures are usually erected as a complex of structures, including water-lifting, culvert, drainage, transport, energy, etc. Such a complex of structures is called a hydroelectric complex. Depending on the purpose, there may be energy, irrigation or navigable (transport) hydroelectric facilities. However, in most cases, complex hydroelectric facilities are built that simultaneously solve several water management problems.

Hydrotechnical construction creates an intensive engineering impact on natural conditions, changing the position of the basis of erosion of the surrounding territory on the reservoir site, causing a change in the conditions of supply and movement of groundwater, activating slope processes (landslides), changing the microclimate of the area, etc. In addition, the creation of reservoirs with a large supply of water can cause catastrophic flooding of the river valley below the structure in the event of an accident. All this requires a particularly careful study of the area where hydroelectric facilities are located.

In the design process, based on the purpose of the structures and specific environmental conditions, the most rational alignment of the location of the main structures of the hydroelectric complex, its layout, the choice of the type and parameters of water structures, the depth of insertion and support on the base rocks, interface with the rock mass at the junctions with the sides of the valley , as well as schemes for the production of construction works.

The history of dams shows that those whose destruction caused terrible catastrophes collapsed in 2/3 of the cases, not due to errors in calculations or in the choice of material, but due to flaws in the foundations - on poor soils, often saturated with water, which was the result of insufficient awareness on the geological and hydrogeological conditions of the foundation soils. An example of this is the accident at the Vaiont reservoir in Italy.

In 1959, at the VI Congress on Large Dams, the Italian hydraulic engineers L. Semenza, N. Biadene, M Panchini reported on the world's highest arch dam on the river. Vaiont, 265.5 m high (70 km north of Venice). The report covered the design features of the dam in great detail. To discharge flood waters on the crest of the dam, a spillway with 10 holes, each 6.6 m long, two tunnel and one bottom spillway was provided. To strengthen the foundation of the dam, an areal grouting of the rock is provided, with a drilling volume of 37,000 m3. To prevent seepage under the dam and on the banks, a grout screen was installed with a drilling volume of 50,000 m3. The calculation of the dam was carried out by 4 analytical methods (independent arches, test loads, etc.). In addition, the design of the dam was studied on two models at the Institute in Bergamo (scale 1:35). Model tests made it possible to lighten the dam due to some reduction in its thickness. About the geological conditions, it was only said that the Vayont valley is composed of limestones and dolomites, characteristic of the eastern Alps, that the layers fall upstream of the river and this is favorable for supporting the dam (Fig. 1).

The construction of the dam was completed in 1960, and on October 9, 1963, one of the most terrible disasters in the history of hydrotechnical construction, as a result of which more than 2,600 people died. The cause was a landslide that hit the reservoir. The world's tallest thin arch dam survived, all the calculations of the designers turned out to be correct. As the analysis of materials after the catastrophe showed: geologists did not take into account the fact that limestone layers form a synclinal fold, the axis of which coincides with the direction of the valley. At the same time, the northern flank is dissected by a fault. In 1960, a landslide with a volume of 1 million m3 formed on the left bank near the dam.

In 1960-1961. a 2-kilometer catastrophic spillway tunnel was breached if landslides resume. To monitor the development of landslide processes, a network of geodetic benchmarks was laid, but as it turned out, the benchmark did not cut the main sliding surface. From 1961-1963 a continuous gravitational creep was observed. Late in the evening on October 9, 1963, 240 million m3 of soil moved into the reservoir in 30 seconds, at a speed of 15-30 m/s. A huge wave 270 meters high in 10 seconds crossed the 2-kilometer reservoir of the reservoir, overflowed the dam and, sweeping away everything in its path, collapsed into the valley. Seismic tremors were registered in Vienna and Brussels.

Rice. 1. Geological section of the valley of the river. Vaiont (Italy): 1 - Upper Cretaceous; 2 - lower chalk; 3 - malm; 4 - dogger; 5 - layas. Numbers in circles: 1 - main sliding surface; 2 - slumped block; 3 - fault; 4 - bottom of the glacial valley; 5 - direction of ancient cracks; 6 - direction of young cracks; 7 - reservoir

2. Waterworks

A hydroelectric power station on a flat river includes a hydroelectric power station. In order for the turbines of a hydroelectric power plant to work, not only a continuous flow of water is required, but also a head - the difference in levels between the upper and lower pools, i.e. sections of the river upstream and downstream of the hydroelectric power station. The pressure is concentrated in a place convenient for use as a result of the construction of a dam or other water-retaining structure and the filling of the reservoir. These two elements are important components of the hydroelectric complex. The reservoir is also necessary to regulate the uneven flow of the river, bringing it into line with water consumption, i.e. in this case, with the schedule of the electrical load of the hydroelectric power plant. Hydroelectric power plants on high-water lowland rivers are located in their channel and are called either channel low-pressure or near-dam, if the pressure is large enough.

Since it is not economically feasible to accumulate rare high-water floods in the reservoir, and since the consumption of electrical energy, i.e. the use of the water reserve may be interrupted due to an accident, the hydroelectric complex must have a spillway to pass water from the upstream to the downstream, in addition to turbines, in order to avoid overflowing the reservoir and overflowing water through the dam with the ensuing destructive consequences. The passage of water to the downstream, in addition to the turbines, in the event of stopping the units of a hydroelectric power plant, may also be necessary when the reservoir is not filled, if without the flow of this water, water users located down the river - hydroelectric power stations, water transport, irrigation systems, etc. will suffer damage. To solve this problem, culverts with deep holes - water outlets - are built as part of the hydroelectric complex.

The passage of water into the downstream may also be necessary for the purpose of emptying the reservoir for inspection and repair of the hydroelectric facilities. Then, in its composition, spillways with deep or bottom holes should be provided. In order to supply a large amount of water for its main purpose - to the turbines of a hydroelectric power station, having cleaned it of dangerous inclusions - ice, sludge, sediment, litter, etc., special structures are needed - water intakes.

A hydroelectric power station can be located on a mountain river not at the dam, but downstream on the shore; water is supplied to it from the water intake by a special conduit and diverted from it into the river also by a special conduit, which together are called derivation, and separately - inlet and outlet derivations. The purpose of the derivation device is the same as the construction of the dam, the concentration of pressure for its convenient use. In mountain rivers, water falls with a large slope of the surface, dissipating its potential energy. A channel laid along the coast with a minimum slope brings water to a hydroelectric power station with a surface level that differs little from the level of the upstream.

As a result, the station uses a greater pressure, the fall of a larger section of the river, not only due to the backwater of the dam, but also due to the difference in the slopes of the river and the channel. The role of diverting derivation is similar; the water level in it differs little from the water level in the river at the end of the derivation, so that at the beginning of the diverting derivation near the hydroelectric power station, the level is lower than nearby in a parallel-flowing river. Thus, the station acquires even greater pressure, using the fall of an additional section of the river. Derivative hydroelectric facilities have a large extent, therefore, they include a head unit with a dam, a spillway and a water intake, a station unit with a pressure basin that completes the inlet derivation, pipelines supplying water to the turbines, and a hydroelectric building and the previously mentioned derivation elements.

Rice. 2. Run-of-river low-pressure hydroelectric complex with a hydroelectric power station and a shipping lock

On fig. 3 shows a hydroelectric power plant with a short diversion channel on a mountain river. The head unit includes a concrete spillway dam, a water intake with a sedimentation sump. The station junction includes a pressure basin and an idle spillway. On fig. 9 shows, partly in section, an underground hydroelectric power plant with tunnel diversion. A high spillway dam, a deep water intake, as well as an equalization reservoir at the end of the pressure inlet part of the derivation are visible.

Rice. 3. Hydroelectric plant with diversion channel

In the presence of a dam, a hydroelectric complex should include spillways, as well as water outlets necessary for navigation. Both of these functions are often combined in one structure. As a result of the construction of the dam, a difference (level difference) arises between the pools, to overcome which ships, both going upstream and going downstream, need navigation facilities (locks, ship lifts. Often, a port is built next to the hydroelectric complex with a water area protected from storm waves, berths, backwater for the wintering of ships.

Approach channels to the navigation pass, upstream and downstream, form a kind of derivation along which ships go, but little water flows, only to fill and empty the lock chamber in the process of ships locking. Sometimes these channels acquire a considerable length, if it is necessary to bypass a section of the river that is inconvenient for navigation - straighten a steep bend, bypass the rapids. Canals of great length with many locks connect different rivers with each other.

The use of water resources for irrigation of agricultural lands and watering of arid territories requires the construction of its own complexes of hydraulic structures, imposes its own requirements on the regulation of the river flow. The area of ​​irrigated land is usually very large, and the hydraulic structures located on it are so numerous that their complex cannot be called a hydroelectric complex, they are called an irrigation system. Part of the structures, compactly located on the used river, as part of a dam that forms a reservoir for regulating the flow of the river, a spillway for flood passage, a water intake and a sump for settling sediments from water taken for irrigation, is called the head node of the irrigation system.

From the head node to irrigated lands, water is supplied by a main water conduit, most often a canal. Its length is measured in tens and hundreds of kilometers, distributors branch off from it along the way, and sprinklers from them. Unused residual water from the fields is collected by collectors and discharged into the watercourse. If part of the irrigated lands is located above the water level in the main canal, water for these lands is supplied by pumping stations. Regulators, drops, waste facilities, etc. are located on the irrigation network itself.

Drainage systems in areas of excessive moisture of the land, the spread of swamps, of course, do not require the construction of dams. The complex of structures of these systems includes drainage, small and large channels, various structures on the drainage network; straightening works are carried out on watercourses (straightening, clearing, deepening, coastal dams). The drainage system may be gravity-fed, however, if the terrain is too flat, pumping stations may be required on the network and to pump water into the watercourse.

The complex systems of water supply - water disposal (sewerage) are very complex and diverse. The diversity depends mainly on the type of water consumer - domestic or industrial water supply. Many industries require a continuous supply of large masses of water, such as pulp and paper, metallurgical, chemical, thermal (and nuclear) power plants (for cooling condensers). Before the rest of this water, changed in its quality (waste water), is discharged into the watercourse or returned to production (circulating water supply), it must be cleaned, disinfected, cooled, etc. As part of an integrated water supply and sanitation system, in addition to the head node of the facilities on the river and the water conduit network at the consumer, there are pumping stations and a system for treating water taken from the watercourse, as well as a more complex system for treating water removed from the consumer.

3. Reservoirs

Reservoir - an artificial reservoir of considerable capacity, usually formed in the river valley by water-retaining structures to regulate its flow and further use in the national economy. In table. 1 shows the largest reservoirs in the world.

Table 1. The largest reservoirs in the world

The following main elements and zones are distinguished in the reservoir (Fig. 4).

Rice. 4. Main elements and zones of the reservoir. The main elements of the regime: 1 - low water level up to backwater; 2 - flood level to backwater; 3 - normal retaining level; 4 - flood level under backwater conditions

The throughput capacity of a hydroelectric complex (its turbines, spillways, bottom openings, locks) is limited for economic and less often technical reasons. Therefore, when there is a flow of very rare frequency in the reservoir (once every hundred, thousand, or even ten thousand years), the hydroelectric complex is not able to pass the entire mass of water flowing along the river. In these cases, the water levels in the entire reservoir and at the dam rise, increasing its volume, sometimes by a significant amount; increases at the same time throughput hydroelectric complex. Such a rise in the level above the FSL during the passage of high floods of rare frequency is called forcing the level of the reservoir, and the level itself is called forced retaining (FPU). On reservoirs used for water transport or timber rafting, the level drawdown during the navigation period is limited to the level at which the river fleet can continue normal operation due to the state of the depths. This level, located between the NPU and ULV, is called the level of navigation drawdown (ONS). The water levels, especially at FSL and FPU, at the dam, in the middle and upper zones of the reservoir are not the same. If the level at the dam corresponds to the FSL mark, then as you move away from it, it rises first by centimeters, and then by tens of centimeters. This phenomenon is called the backwater curve.

In addition to the great and undoubted benefits that reservoirs bring, after their filling, there are accompanying, often negative consequences. These include the following. The greatest damage to the national economy is caused by the constant flooding of territories with settlements located on them, industrial enterprises, agricultural land, forests, subsoil, iron and highways, communication and power lines, archaeological and historical monuments and other objects. Permanently flooded areas are areas located below the normal retaining level. Temporary flooding of territories located on the banks of reservoirs ranging from normal to forced retaining levels also causes damage, but occurs rarely (1 time in 100 - 10,000 years).

An increase in the level of groundwater in the territory adjacent to the reservoir leads to its flooding - swamping, flooding of underground structures and communications, which is also unprofitable.

Reformation (processing) of the banks of reservoirs by waves and currents can lead to the destruction of large areas of useful, developed territory. Landslide processes occur or become more active along the banks of reservoirs. The conditions of navigation and timber rafting on the river are radically changing, the river turns into a lake, the depths increase, the speeds decrease. The underbridge dimensions required for water transport are reduced.

The winter regime of the river changes greatly, the ice cover on the reservoir lengthens, the sludge disappears, if it was. Turbidity decreases as sediment settles into the reservoir.

Among the measures to compensate for the damage caused by flooding and underflooding of land, they carry out the transfer and restoration of cities, workers' settlements, collective farm estates, and industrial enterprises in new unflooded places. They carry separate sections of roads, build up their canvas, strengthen the slopes of embankments, etc. Transfer or protect monuments of history and culture, and if this is not possible, study and describe them. Bridge spans are raised and bridge crossings are rebuilt. River boats are being replaced by a lake fleet, mole rafting is being replaced by raft towing. Produce logging and forest clearing of the territory of the reservoir. Complete the development of minerals (for example, coal, ores, building materials etc.) or provide the possibility of their subsequent development in the presence of a reservoir. Sometimes it turns out to be economically feasible instead of removing economic objects and settlements from the flood zone of the reservoir to implement measures for their engineering protection.

The complex of hydrotechnical and land reclamation measures, united by the name engineering protection, includes embankment or fencing of objects and valuable lands, drainage of flooded or embanked areas with the help of drainage and pumping out water, strengthening the banks in certain sections of the reservoir, etc.

4. Dams

A dam is a structure blocking a watercourse, which props up water to a level higher than that of a household, and thus concentrates in one place a pressure convenient for use, i.e., the difference in water levels in front of and behind the dam. The dam occupies an important place in the composition of any pressure hydroelectric complex.

Dams are being built in various climatic and natural conditions - in the northern latitudes and in permafrost areas, as well as in the south, in tropical and subtropical zones, with high positive temperatures. Their location is high-water lowland rivers flowing in channels composed of non-rocky soils - sands, sandy loams, loams and clays, as well as mountain rivers flowing in deep rocky gorges, where strong earthquakes often repeat. The variety of natural conditions, the purpose of creating dams, the scale and technical equipment of construction has led to a variety of their types and designs. Like other structures, dams can be classified according to many criteria, such as height, the material from which they are built, the ability to pass water, the nature of their work as retaining structures, etc.

Hydraulic water-retaining structures, which include dams, perceive forces of different origin, nature and duration, the total effect of which is much greater and more complex than the effect of forces on buildings and structures of an industrial-civil type.

To understand the working conditions of water-retaining structures, consider the scheme of a concrete dam with the main loads acting on it. Like all extended concrete structures, the dam is cut into sections with seams that allow the sections to deform freely under temperature effects, shrinkage and precipitation, which prevents the formation of cracks. The following forces act on each section of the dam with a length L, a height H and a width along the base B.

The weight of the dam section G is determined by its geometric dimensions and the specific gravity of concrete g=rґg (as you know, the specific gravity of a substance is equal to the product of its density and the acceleration of free fall).

Rice. Fig. 5. Transverse profiles of modern dams in comparison with the silhouettes of other structures (dimensions in meters): 1 - Dnieper; 2 - Bukhtarma; 3 - Krasnoyarsk; 4 - Brotherly; 5 - Charvak; 6 - pyramid of Cheops; 7 - Toktogul; 8 - Chirkeyskaya; 9 - Sayano-Shushenskaya; 10 - Usoi blockage; 11 - Nurek; 12 - Moscow State University; 13- Inguri

The pressure of filtering water on the foot of the dam arises due to the underground flow of water flowing under pressure through the pores and cracks in the soil of the base of the dam from the upstream to the downstream. The approximate value of this force, called backpressure, is:

U=ґgBL,

where H1, H2 are the water depths in the pools; g is the specific gravity of water; a is a reduction factor that takes into account the effect of impervious devices and drainage at the dam base.

The hydrostatic water pressure from the upstream and downstream sides is determined by the formulas:

W1=gH12L/2; W2=gH22L/2.

The forces listed above belong to the category of the most important and constantly operating. In addition to them, in necessary cases, according to special formulas, the dynamic pressure of waves, the pressure of ice, sediment deposited in the reservoir, as well as seismic forces are taken into account. An additional effect on the strength of a concrete dam is exerted by uneven temperature fluctuations. The cooling of the dam surfaces causes tensile stresses in them, and cracks can form in concrete that weakly resists them. Under the conditions of the listed forces and water pressure, the dam must be strong, resistant to shear and watertight (this requirement also applies to its foundation). In addition, the dam must be economical, i.e. of all the options that meet the above requirements, the option characterized by the minimum cost should be selected.

A special place in hydraulic engineering is occupied by issues related to the filtration of water from the upstream to the downstream. This phenomenon is inevitable, and the task of hydraulic engineering is to predict and organize it, and to prevent dangerous or unprofitable consequences with the help of engineering measures. The paths of filtration currents can be: the body of the structure, even if it is built of concrete; the foundation of the structure, especially when it is non-rocky or fractured rock; shores in the places where pressure structures adjoin them. The harmful effects of filtration are unproductive losses of water from reservoirs, which is thus not used for national economic purposes, back pressure, which reduces the degree of stability of the penstock, and filtration disturbances or deformations of the body of an earth dam or non-rock foundation, in particular, in the form of suffusion or uplift.

Suffusion is usually called the removal of the filtration flow small particles through pores between larger particles; it occurs in non-cohesive (loose) soils - inequigranular sandy, sandy-gravelly. During chemical suffusion, salts deposited in rocks are dissolved. Upstream is the removal by an underground stream filtering from under a pressure structure into the downstream of significant volumes of base soil, consisting of cohesive rocks, such as loams, clays, etc.

To ensure the normal operation of the facility and liquidation hazardous phenomena when designing a structure, a rational underground circuit is provided (Fig. 6). This is achieved by increasing the filtration path under the structure, creating a waterproof coating in the upstream (ponura) and a powerful water break in the downstream, laying sheet piles or other curtains, teeth, or other measures.

Rice. 6. Scheme of a dam on a filter base (according to S.N. Maksimov, 1974): 1 - dam body, 2 - water break, 3 - apron, 4 - ponur, 5 - streamlines, 6 - sheet piles

Dams from soil materials.

An ancient type of pressure hydraulic structures are dams made of soil materials. Depending on the soils used, dams are either homogeneous or heterogeneous; in the transverse profile, the body of the latter consists of several types of soils. For the construction of a homogeneous earth dam, various low-permeable soils are used - sand, moraine, loess, sandy loam, loam, etc. In terms of the design of the dam and its interface with the base, this is the simplest type of pressure structure.

Heterogeneous earth dams, in turn, are divided into dams with a screen made of low-permeability soil, laid from the side of the upper slope of the dam, and dams with a core, in which low-permeability soil is located in the middle of the dam profile. Instead of a soil core, non-soil diaphragms made of asphalt concrete, reinforced concrete, steel, polymers, etc. can be used. Screens can also be made from these non-soil materials.

Depending on the method of work, earth dams are bulk, with mechanical compaction of the poured soil, and alluvial, erected with the help of hydromechanization; The latter method of erecting earth dams, provided that appropriate conditions exist (supply of water, energy and equipment, availability of a suitable soil composition, etc.), is characterized by high productivity, reaching up to 200 thousand m3 / day.

Rock-and-earth dams are erected in the main part of the volume from a riprap of stone; their water resistance is achieved by the construction of a screen or core laid from low-permeable soils (loams, etc.). Between the stone and the fine-grained soil, return filters are arranged - transitional layers of sand and gravel with fineness increasing towards the stone, in order to prevent suffusion of the soil of the impervious devices.

Such dams have been found wide application in high-pressure waterworks on mountain rivers. So, the height of the dam of the Nurek hydroelectric power station on the river. Vakhsh is 300 m.

Their advantage, in comparison with other types of dams, is the use of stone and soil available at the construction site, the possibility of extensive mechanization of the main types of work (rock throw and soil filling), as well as sufficient seismic resistance. Compared to other types of earth dams, rock-and-earth dams are characterized by a steeper slope, i.e. less material.

The small width of the low-permeable contact of the rock-and-earth dam with the foundation complicates the design of their waterproof interface. In non-rocky soils, sheet piling or laying of a concrete spur is required, and in rocky soils, a grout curtain is installed by injecting cement mortar through drilled wells into rock cracks. Such interfaces prevent dangerous filtration phenomena at the base of pressure structures.

Rock-fill dams are built by throwing or filling stones, and their water resistance is ensured by a screen on the upper slope or a diaphragm in the middle of the profile, constructed from non-soil materials (reinforced concrete, wood, asphalt concrete, steel, plastics, etc.). Stone dams are built from dry masonry, which also requires baffles, or from mortared masonry. These dams are now rarely built.

Dams made of artificial materials.

Wooden dams are one of the oldest types of pressure structures, dating back many hundreds of years. In these dams, the main loads are perceived by wooden elements, and their stability against shear and floating is ensured by fixing wooden structures in the base (for example, by driving piles) or loading with stone or soil ballast (in woven structures). Wooden dams are built for small heads, from 2 to 20 m.

Fabric dams began to be erected relatively recently due to the advent of durable waterproof synthetic materials. The main structural elements of fabric dams are the shell itself, filled with water or air and playing the role of a gate (weir), anchor devices for attaching the shell to the concrete flute, a piping system and pumping or fan equipment for filling and emptying the shell. The area of ​​application of fabric dams rarely goes beyond the pressure limit of 5 m.

Concrete dams are widely used in hydraulic engineering construction. They are built in various natural conditions and allow water to overflow through special spans on their crest (spillway dams), which is impossible or irrational in dams made of soil materials. Their structural forms are very different, which depends on many factors. The highest height of the Grand Dixans (Switzerland) gravity-type concrete dam is 284 m. In Russia, the Sayano-Shushenskaya dam of the arch-gravity type on the Yenisei is 240 m high. The dam has a rocky foundation. The spillway dams of the Svir and Volga cascades were built on a non-rocky foundation in difficult geological conditions. Lightweight concrete dams appeared later than massive ones and are relatively uncommon in Russia. By design, concrete dams are divided into three types: gravity, arch and buttress. The most famous type of these dams are buttress dams. Their advantage over massive ones is a smaller amount of concrete work. At the same time, they require more durable concrete, reinforcing it with reinforcement.

Gravity dams, when exposed to the main forces of hydrostatic pressure, provide sufficient shear resistance, mainly due to their large dead weight. In order to combat water filtration at the base of the dam, grouting curtains are arranged (in rocky foundations), sheet piles are hammered (in non-rocky foundations). To increase the stability of the dam, drainage is organized, cavities are arranged to reduce back pressure, and other measures are taken.

Arched dams are curvilinear in plan with a convexity towards the upstream; they resist the action of hydrostatic pressure and other horizontal shear loads, mainly due to their abutment against the banks of the gorge (or abutments). When constructing arch dams, a mandatory requirement is the presence of sufficiently strong and slightly pliable rocks in landfalls. These dams do not require, like gravity dams, a significant weight of concrete masonry, they are more economical than gravity dams. The radii of curvature of their arched elements increase from bottom to top.

Buttress dams consist of a number of buttresses, the shape of which in the side facade is close to a trapezoid, located at a certain distance from each other; buttresses are supported by pressure head floors, which perceive the loads acting from the upstream side. The spans of the bridge crossing rest on the buttresses from above. In turn, the buttresses transfer the load to the base. The following varieties of buttress dams are best known: massive buttress, with flat ceilings, multi-arch. Buttress dams are both deaf and spillway. They are built on rocky and non-rocky soils; in the latter case, they have an additional structural element in the form of a foundation slab, the purpose of which is to reduce stresses in the foundation soil. To give greater seismic resistance to buttresses in transverse seismic conditions (across the river), they are sometimes connected with each other by massive beams.

A feature of buttress dams is the increased width along the base and the slope of the upper face, which leads to the fact that a significant vertical component of water pressure is transferred to the latter, pressing the dam to the base and providing it with shear stability, despite the reduced weight. The backpressure in such dams is less than in massive gravity dams.

Buttress dams require less concrete volumes than gravity dams, but the cost of improving the quality of concrete, reinforcement and complicating the work makes them quite close to each other in terms of economic indicators. The highest buttress (multi-arch) dam Daniel-Johnson 215 m high was built in Canada.

5. Spillways

As part of the hydroelectric complex, in addition to the blind dam, spillways are of great importance, i.e. devices for dumping excess flood waters or passing expenses for other purposes. There are several different solutions for the location of spillways in the hydroelectric complex.

Spillway spans can be arranged in the crest of a concrete dam in the channel or on the floodplain of the river; then the structure will take the form of a spillway dam. The spillway can be arranged independently of the dam in the form of a special structure located on the coastal slope and therefore called the coastal spillway.

Both in the body of the dam and on the bank slope, spillways can be placed close to the dam crest or deep below the headwater level. The first are called surface, the second - deep or bottom spillways.

The surface spans of spillway dams may be open (without gates), but they usually have gates to control the upstream water level. To prevent the overflow of the reservoir, the gates are opened partially or completely, preventing the water level from rising above the mark of the normal retaining level (NSL). To improve the conditions for the passage of water through the dam, its crest is given a smooth, rounded outline, which then turns into a steeply dipping surface, ending near the level of the tailwater with another reverse rounding, directing the flow into the riverbed. The entire length of the spillway is divided by bulls into a series of spans. The bulls, in addition, perceive the water pressure from the gates, and also serve as supports for bridges intended for servicing lifting mechanisms and gates and transport links between the banks.

Water discharged through the dam has a large supply of potential energy, which is converted into kinetic energy. The fight against the destructive energy of the flow discharged through the dam is underway different ways. Behind the spillway dam on a water-breaking massive concrete slab, energy absorbers are arranged in the form of separate concrete masses - checkers, piers or reinforced concrete beams. Sometimes, in the downstream of a spillway dam, a surface regime is organized by arranging a ledge and a toe in the lower part of the spillway, breaking off from it at a higher speed, the flow concentrates at the surface, and under it a roll is formed with moderate reverse velocities near the bottom.

Behind the spillway dams, which have non-rocky rocks at the base, behind the water breaks, an apron is made - a fortified permeable section of the river bed.

Usually, spillways are located on the shore in hydroelectric facilities with dams made of soil materials that do not allow water to flow through their crest, as well as in hydroelectric facilities with concrete dams in narrow gorges, where the channel is occupied by a hydroelectric power station near the dam. Their types are very diverse. The most commonly used are surface spillways, in which the discharged stream flows along the surface of the coast in an open recess. They are located on one or two banks, often near a dam, and have the following components: an inlet channel, a spillway proper with spillways, piers and gates (or automatic action without gates), a discharge channel in the form of a fast current or a stepped drop (used rarely). Coastal spillways are completed with water-breaking devices, similar to those that are arranged in the downstream of spillway dams - a water well.

If local conditions prevent tracing a diversion channel, then it can be replaced by a diversion tunnel; a tunnel-type coastal spillway will be obtained. Tunnel coastal spillways have the following components: an inlet channel located at high elevations of the coastal slope in the upstream, the outlet structure itself with gates and a discharge tunnel ending with a section of the channel and a water-breaking device.

Deep and bottom spillways are located at elevations close to the bottom of the watercourse on which the hydropower plant is being built. They are arranged for the following purposes: to pass the river flow during the construction of the dam in the riverbed (construction spillways), and in some cases to pass all or part of the discharge. Their main varieties are tunnel and tubular spillways. Spillway tunnels are located in rocky coastal massifs, bypassing the dam, their length is several hundred meters, the cross-sectional dimensions are determined by the flow rate. The cross-sectional shape of construction spillways is usually horseshoe-shaped. The remaining tunnels, operating under high pressure, have a circular cross section.

Tubular spillways are located in the hydroelectric complex depending on the type of dam. If the dam is concrete (gravitational, buttress or arched), then spillways are pipes that cut through its body from the upstream to the downstream and are equipped with gates. If the dam is earthen, then tubular spillways are arranged under the dam, deepening them into the base. They are a tower from which steel or reinforced concrete pipes of round or rectangular cross section originate, depending on the pressure. They can be single or assembled into a kind of "batteries" depending on the flow. Gates and control mechanisms are placed in the inlet and outlet parts of the pipes.

Gates and lifts. The main gates are used to regulate discharge flows and water levels in the upper pool, as well as to pass in some cases forests, ice, litter, sediments. They can completely or partially close culverts. The design of gates depends on their location; shutters of surface openings, often large, perceive a relatively small hydrostatic pressure; deep hole valves, which are much smaller, experience high hydrostatic pressure. Gates are most often made of steel, with small pressures and spans of blocked holes - from wood, in low-pressure non-critical structures with large spans - from fabric materials (fabric dams). The most widely used in hydraulic structures are flat gates, which are a metal structure in the form of a shield moving in vertical grooves of bulls and abutments. The components of a flat gate are: a waterproof casing that perceives the pressure of the upstream water, then a system of beams, trusses and support structures that roll or slide along special rails embedded in the grooves. The mass of the movable part of the shutters is quite significant, at high altitudes and spans it exceeds 100 tons, which requires powerful lifting mechanisms. To reduce the lifting force of mechanisms, segmental gates are used, which, when they are raised and lowered, rotate around hinges embedded in bulls and abutments. Such valves are also widely used, but their cost exceeds the cost of flat valves.

6. Water inlets

hydroelectric dam plain reservoir

Purpose of the water intake. Water intakes are called parts of water intake structures, the main purpose of which is the intake of water from a watercourse (river, canal) or reservoir (lake, reservoir); the action for which they are intended can be called water intake.

The consumer usually regulates the flow of water. Water intake should be ensured at any retaining level - from normal (NCL) to the lowest - dead volume level (DSL).

The functions of the water intake facility include water purification from impurities and foreign bodies.

Water intake structures. The design and equipment of the water intake largely depend on the type of waterworks and on the type of water conduit - pressure or non-pressure. Therefore, a description of the structures and equipment of water intakes and their operation is possible only separately for each type. The dimensions of the water intake are characterized by the dimensions of its inlet section, where the trash-retaining grates are located (often they are called trash-retaining). To facilitate cleaning of the gratings and reduce pressure losses on the gratings, the flow velocity at the inlet is assumed to be no more than 1.0 m/s. The inlet area of ​​water intakes of large turbines is measured in hundreds of square meters.

The water intake of this type, individual for each turbine, is a rectangular hole in the dam mass, gradually narrowing and turning into a circular section of the turbine conduit.

The upper part of the entrance is closed with a reinforced concrete wall - a visor lowered below the ULV. The visor perceives the pressure of ice, detains floating objects. In front of the entrance to the water intake, a grate 1 of strip steel rods is installed to retain debris suspended in the water, which could damage the turbine. During operation, the debris accumulated at the water intake and on the grate is removed with a mechanical rake, grab, since when the grate becomes clogged, its resistance to water flow will increase significantly.

Behind the grating in the bulls, grooves are arranged to install the gate 3 and stop the water supply to the turbine conduit. In order to be able to maintain and repair the quick-acting shutter, grooves 2 for the repair shutter are arranged in front of it. You can get to the shutter for inspection and repair through the inspection hatch 6. The repair shutter is simpler, it does not require speed, it does not fall into the stream, but into calm water. Behind the gate, an air duct 7 is arranged - a pipe for supplying air to the turbine conduit, replacing the water leaving through the turbine in the event that the water intake is closed by an emergency repair gate. For ease of operation, a building equipped with an overhead assembly crane is being erected above the water intake. In favorable climatic conditions, the building is not built and a gantry crane is used.

The main gate regulates the water flow in accordance with the water consumption schedule. The movement of the shutter is carried out using a hydraulic drive.

With small fluctuations in the level of the upper pool, the water intake structure is located at high elevations of the coast, this is the so-called surface coastal water intake. With a wide range of operating levels of the reservoir, it is necessary to arrange a deep coastal water intake, placing it slightly below the ULV.

7. Water conduits

Purpose of conduits. The water that enters the water intake and is purified from impurities must be left to the consumer in accordance with the consumption schedule. One of the main requirements for conduits (pressure and non-pressure) is the water tightness of their walls. Water should not be lost along the way, and these losses should not swamp the surrounding area. For a hydroelectric power plant, it is also necessary that the potential energy of the flow be lost along the way as little as possible, the slope of its free or piezometric surface should be small. To do this, the walls of the conduit must be smooth, characterized by low resistance to flow. Smooth walls are needed for water conduits and irrigation systems and water supply systems - the higher the water is brought, the easier it is to ensure its gravity flow to consumers, the lower the energy costs for the operation of pumping stations. Only for shipping channels, the roughness of the walls does not matter, since the speeds in them are small or equal to zero.

The walls of conduits should not be washed away by current velocities and waves (waves occur, for example, when ships move along canals).

The dimensions of the cross section of the conduit are determined on the basis of technical and economic calculations. The type and design of the conduit is also determined on the basis of technical and economic comparisons. Depending on the purpose of the conduit, its size, natural conditions and conditions of construction and operation, channels, trays, pipelines, tunnels can be used as a conduit. The first two types are non-pressure, the third is pressure; the tunnel can be both pressure and non-pressure (if it is not filled with water to the top). Often the optimal solution is achieved by a consistent combination of different types of conduit sections.

The simplest and cheapest type of conduit is usually a canal. Channels are common in all areas of hydraulic engineering. It is advisable to lay the canal route on the plan so that the water in it is in the recess, the height of the dams is small. The cross-sectional shape is trapezoidal (sometimes of a more complex shape), the steepness of the slopes is determined by their stability; the ground must not slip.

In rocky soil, the cross section of the channel approaches a rectangular one. The width of the channel section is greater than its depth in order to reduce water losses due to filtration from the channel, increase the flow rate and reduce the resistance to flow, i.e. the slope of the surface, the bottom and slopes of the channel are covered with cladding, most often concrete or reinforced concrete. A layer of coarse-grained soil (gravel) is laid under the lining as a drainage.

The tunnel is the most expensive type of conduit per unit of its length. If the tunnel is laid in weak, non-rocky soils, then its cost increases especially. In this regard, it can be preferred to surface types of derivation only if it is much shorter, allows you to straighten the route, or if the coastal slope along which the route can be laid is of little use for surface derivation - very rugged terrain, high steepness, landslides, avalanches .

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Physical and geographical conditions of runoff formation. water bodies Krasnodar Territory: rivers, lakes, estuaries, reservoirs. Pollution of water bodies. The problem of non-centralized sources of water supply. The current state of hydraulic structures.

thesis, added 07/20/2015


Geographical position of the Berezovsky reservoir. Engineering-geological and hydrogeological conditions of the reconstruction site. Determining the volume of earthworks and organizing the construction of the designed structures during the reconstruction of the reservoir.

term paper, added 01/25/2015


Calculation of the main channel of a hydraulic structure, determination of the uniform movement of fluid according to the Chezy formula. Determination of the channel of the most hydraulically advantageous section, depths for given flow rates. Calculation of the multistage difference.

term paper, added 07/12/2009


Tracing of linear structures. The goals of engineering and geodetic surveys for linear structures. Geodetic work in the design of linear communications and in the laying of routes for structures. Establishing the position of the road in the longitudinal profile.

test, added 05/31/2014


Hydrological characteristics of the design area. Determination of useful, forced and dead volumes of the reservoir. Selection of the dam alignment, culvert routes. Construction of the plan and transverse profile of the dam. Calculation of the input cap.

Hydraulic structure is an engineered or natural structure for the use of water resources or to combat the destructive effects of water. Hydraulic structures are general and special . General ones are used for almost all types of water use: water-retaining, water supply, regulatory, water intake and spillway.

Water-retaining hydraulic structures create a pressure or difference in water levels in front of the structure and behind it. These include: dams and dikes (or ramparts).

Dams - the most important and most common type of hydraulic structures. They block the river channels and create a level difference along the riverbed. Upstream of the dam, water accumulates and an artificial or natural reservoir is formed. The section of a river between two adjacent dams on a river, or the section of a canal between two locks, is called a pool. The upstream of the dam is the part of the river above the retaining structure, and the part of the river below the retaining structure is called the downstream. Reservoirs can be long-term or short-term. A long-term artificial reservoir is, for example, a reservoir upstream of a hydroelectric dam, an irrigation system. A long-term natural reservoir can be formed as a result of the blocking of the river after such an emergency as the collapse of hard rocks. Short-term artificial dams are created to temporarily change the direction of a river's flow during the construction of a hydroelectric power station or other hydraulic structures. Short-term natural dams arise as a result of blocking the river with loose soil, snow or ice. Dams fence off the coastal area and prevent its flooding during floods and floods on rivers, during high tides and storms on the seas and lakes.

Water-conducting hydraulic structures (water conduits) serve to transfer water to specified points: canals, hydrotechnical tunnels, trays, pipelines. Some of them, for example, canals, due to the natural conditions of their location, the need to cross communication lines and ensure the safety of operation, require the construction of other hydraulic structures that are combined into a special group of structures on canals (aqueducts, siphons, bridges, ferry crossings, gates, spillways, slugs, etc.).

Regulatory (straightening) hydraulic structures designed to change and improve the natural conditions of the flow of watercourses and protect riverbeds and banks from erosion, sedimentation, ice exposure, etc. When regulating rivers, dams, jet guides (semi-dams, shields, dams, enclosing shafts, traverses, bottom rapids, etc.) .), bank protection structures, ice guides and ice retention structures.

Water intake (water intake) hydraulic structures arranged to take water from a water source and direct it to a water conduit. In addition to ensuring an uninterrupted supply of water to consumers in the right amount and at the right time, they protect water supply structures from ice, sludge, sediment, etc. Water discharge hydraulic structures are used to pass excess water from reservoirs, canals, pressure basins, etc. They can be channel and coastal, surface and deep, allowing to partially or completely empty water bodies. To regulate the amount of released (discharged) water, spillways are provided with hydraulic gates. For small water discharges, automatic spillways are also used, which automatically turn on when the headwater level rises above a predetermined one. These include open weirs (without gates), spillways with automatic gates, siphon spillways.

Special hydraulic structure built for any one branch of the water industry. For water transport: a navigable lock, a ship lift, a pier, a boat, a timber launch (log launch), a lighthouse and other structures according to the situation of the ship's passage, various port facilities (piers, breakwaters, piers, berths, docks, boathouses, slipways, etc.). For hydropower: HPP building, pressure basin, etc. For hydromelioration: irrigation or drainage (main or distribution) canal, drainage, gateway-regulator on the irrigation and drainage system, collector, etc. For water supply and sewerage: capping, pumping station, water pressure tower and reservoir, cooling pond, etc. For fish farming: fish ladder, fish elevator, fish pond, etc. For social organization: swimming pools, water parks, fountains. These hydraulic structures, along with their direct purpose, are used for:

• protection from floods and destruction of the shores of reservoirs, banks and bottom of riverbeds;
• fencing of the storage of liquid industrial waste (mining, metallurgical, energy) and agricultural enterprises;
• erosion protection on channels;
• prevent the harmful effects of water and liquid waste.

In some cases, general and special hydraulic structures are combined in one complex, for example, a spillway and a hydroelectric power station building (the so-called combined hydroelectric power station) or other structures to perform several functions simultaneously. In the implementation of water management measures, hydraulic structures, united by a common goal and located in one place, constitute complexes called nodes of hydraulic structures or hydroelectric facilities. . Several hydro units form water management systems, for example, energy, transport, irrigation, etc. Depending on the location, hydraulic structures can be sea, river, lake, pond. There are also ground and underground hydraulic structures.

To analyze the potential hazard and capital value, hydraulic structures as objects of hydraulic engineering construction are divided into 5 classes. The 1st class includes the main permanent hydroelectric stations with a capacity of more than 1 million kW. To the 2nd - the construction of hydroelectric power plants with a capacity of 301 thousand - 1 million kW, structures on super-main inland waterways (for example, on the Volga, the Volga-Don Canal, etc.) and the construction of river ports with a navigational cargo turnover of more than 3 million conditional tons . To the 3rd and 4th classes - HPP facilities with a capacity of 300 thousand kW or less, facilities on the main inland waterways and local routes, facilities of river ports with a cargo turnover of 3 million conventional tons or less. The 5th class includes temporary hydraulic structures. Accidents at hydraulic structures are diverse. The most dangerous of them are hydrodynamic accidents.

When developing measures to prevent emergency situations at hydraulic structures, depending on their hazard class, the degree of their reliability is assigned in projects, i.e. margins of safety and stability, estimated maximum water consumption, characteristics and quality of building materials, etc. In addition, the scope and composition of survey, design, research and diagnostic work is determined by the hazard class. The characteristic features of hydraulic structures are associated with the impact of water flow, ice, sediment and other factors on it. This impact can be mechanical (static and hydrodynamic loads, soil suffusion, etc.), physicochemical (abrasion of surfaces, corrosion of metals, leaching of concrete), biological (rotting of wooden structures, wear of wood by living organisms, etc.). The conditions for the construction of hydraulic structures are complicated by the need to pass through the structures during the period of their construction (usually for several years) the so-called construction costs of the river, ice, rafted timber, ships, etc. there is flooding of individual land areas, a rise in the level of groundwater, collapse of banks, etc. Therefore, the construction of such facilities requires high quality work and high reliability and safety of structures, because. accidents at hydraulic structures cause serious consequences - human casualties and loss of material values.