RU2474645C1 - Rock and earth dam - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: dam comprises a core from clayey soil, upper and lower transition zones from a non-cohesive soil, upper and lower prisms, at least the lower of which is made from rock riprap, a head of non-swelling soil, a layer from an air-impermeable material and equipment required for operation of the dam. The dam head includes a heated reinforced concrete gallery, between external supports of which there is a section of free surface of the core comb arranged. The layer of the air impermeable materials covers the dam comb and its lower slope, at least within the height of the head and has dark colour. The upper wall of the gallery is made as water impermeable, and the lower wall of the gallery comprises air ducts, which provide for hydraulic connection of the gallery cavity with the pore space of the rock riprap of the head and the lower prism. Equipment may provide for forced motion of warm atmospheric air along the rock riprap of the lower prism via the gallery cavity.

EFFECT: invention provides for positive temperatures near a comb and a lower face of a dam core, core freezing is prevented, and higher dam reliability during its operation.

7 cl, 1 dwg

Description

The invention relates to hydraulic engineering and can be used in the construction of stone and earth dams in the northern climatic zone.

Known stone-earthen dam containing a core of clay soil, the upper and lower transitional zones from incoherent soil, the upper and lower prisms (lateral) of the stone outline and the head of non-porous soil [1].

In such dams built in the northern climatic zone, the upper part of the core has already been frozen from the dam crest to a depth of 9 m or more - Vilyuyskaya 1-2-3, Ust-Khantaysky, Kureyskaya, Kolyma and others. With self-sealing deformations in the lower thawed part of the core and when the frozen head of the dam hangs on the lateral prisms, decomposition of the soil of the core occurs directly at the interface between frozen and thawed soils. Such decompression is dangerous in the suffusion sense, especially in the case of using soils with a low, less than 7 plasticity number in the core — such clay soils prevail in the northern climatic zone. At the same time, during the erection of a stone-earthen dam in especially harsh climatic conditions, the lower prism can freeze and form a continuous waterproof ice-ground massif, which adjoins the permafrost base and the dam core. This occurs especially outside the channel talik at lower coastal sections of the dam. Under such conditions, the frozen bottom transitional zone cannot divert water filtered through the core. Therefore, thawed water-saturated areas preserved in the transition zone and in the lower prism operate in unpredictable extreme conditions, which can lead to emergency situations, as happened at the Kolyma hydroelectric dam, where the average annual air temperature reaches minus 13 ° С [2].

A similar soil dam is known, which additionally includes a thermal curtain, which is placed in the cross section of the dam in the lower transition zone and is made in the form, for example, of a series of wells located in series along the length of the dam and its entire height [2 and 3]. In this dam, the transition zone and drainage at the base of the lower prism are located in the zone of positive temperatures created by the thermal curtain. However, the creation of a thermal curtain along the dam length through deep wells and the operation of this curtain are associated with high costs, while in the dam the upper part of the core and the drainage part of the drainage at the base of the dam are not protected from freezing, which reduces its reliability.

The reliability of such a dam will be enhanced if it is additionally equipped with a means to create a positive temperature in the upper part of the core, and the drainage part of the drainage provides unhindered access to the river, as provided in the source [4]. During operational fluctuations in the downstream of the river water levels in the drainage part of the drainage, positive temperatures are constantly maintained. This occurs due to the periodic entry and exit of river water into the pores of the stone outline of the drainage part of the drainage with an increase or decrease in the water level in the river. However, the costs of creating a thermal curtain in the dam and its operation, as well as maintaining positive temperatures in the upper part of the core remain high.

Known stone-earth dam containing a core of clay soil, the upper and lower transitional zones of incoherent soil, the upper and lower prisms of the stone outline and the head of the non-porous soil, which accommodates a heated reinforced concrete gallery. A section of the free surface of the ridge of the core is located between the outriggers of the gallery, and the upper stack of the gallery is waterproof [5]. The heating gallery creates an efficient and reliably controlled heating of the upper part of the core. However, in such a dam, freezing of the lower prism and the lower transition zone and their freezing with the core in the middle and lower part of the dam is not prevented, which reduces the reliability of the dam.

The closest technical solution to the proposed solution is a stone-earthen dam [6, Figure 1], containing a core of clay soil, upper and lower transition zones from incoherent soil, upper and lower prisms from a stone outline, a screen made of airtight material, a career cloak small things or sand and gravel soil and equipment necessary for the operation of the dam. The screen is located inside the lower prism so that the screen and the bottom face of the core and the surface of the base or water in the channel form a stone duct along the dam near the transition zone, an air duct, the entrance to which is on the crest of the dam, and the outlet on the lower part of its lower slope. At the same time, the dam equipment is able to provide forced movement of warm atmospheric air along the stone outline of the air duct through the cavity of a linear structure (hangar), made on the crest of the dam above the entrance to the air duct, i.e. above the bottom prism, away from the crest of the core. This provides positive temperatures within the air duct, which increases the reliability of the dam. The source [6] also reported that a similar technical solution was filed on 06/06/2010 for the invention No. 2010127897 “Dam from soil materials”. The content of this application to the applicant of the present invention is not yet known.

The disadvantages of this dam are as follows.

1. The airtight screen inside the stone outline and the hangar on the crest of the dam significantly complicate the design of the dam, which leads to an increase in the cost of its construction.

2. The location of the hangar above the entrance to the air duct, ie away from the ridge of the core, does not prevent freezing of the upper part of the core in the cold season, which reduces the reliability of the dam during its operation. In this case, the implementation of the hangar can lead to an increase in the width of the dam crest, which will increase the cost of erecting the dam.

The problem to which the invention is directed, is to reduce the cost of creating a dam and increase the reliability of the dam during its operation.

The technical result from the use of the invention is to simplify the design of the dam and prevent freezing of the core of the dam.

The problem is solved, and the technical result is achieved by the fact that the dam contains a core of clay soil, the upper and lower transition zones of incoherent soil, the upper and lower prisms, at least the lower of which is made of stone, the tip is made of non-porous soil, the layer made of airtight material and equipment necessary for the operation of the dam. The tip of the dam accommodates a heated reinforced concrete gallery, between the outriggers of which there is a portion of the free surface of the ridge core, and a layer of airtight material covers the ridge of the dam and its bottom slope, at least within the height of the tip. The upper wall of the gallery is made waterproof, and the lower wall contains air ducts that provide hydraulic connection between the gallery cavity and the pore space of the stone outline of the head and the lower prism. At the same time, the equipment is able to provide forced movement of warm atmospheric air along the stone outline of the lower prism through the gallery cavity.

Additionally:

- the layer of airtight material has a dark color, and the value of its absorption coefficient of solar radiation (solar radiation, light) is not less than 0.8;

- the gallery is equipped with hatches with closures that can isolate the gallery cavity from direct communication with the atmosphere;

- a predetermined number of air ducts from among those providing a hydraulic connection between the gallery cavity and the pore space of the stone outline are provided with shutters, each of which is installed at the entrance to the air duct from the side of the gallery cavity;

- the equipment is capable of supplying pressure to the gallery cavity by pressure;

- the equipment is capable of discharging air from the gallery cavity by discharge;

- a layer of airtight material is made of asphalt or asphalt concrete.

It is the performance of a heated gallery in the dam head according to the indicated rules, as well as covering the dam crest and partially its downhill slope with an airtight layer made mainly of asphalt or asphalt concrete, which ensures the achievement of the previously indicated technical result by means of the equipment: simplifying the dam design and preventing freezing of the dam core. This simplifies the forced air supply to the stone sketch of the lower prism of the dam. All this reduces the cost of creating a dam by eliminating the internal airtight screen and hangar from the dam design, the functions of which are additionally taken over by the gallery, and increasing the reliability of the dam during its operation by heating the dam head, and therefore the upper part of the core, by the heated gallery.

The proposed dam is illustrated by a drawing, which shows a transverse section of the dam in its channel section.

The dam contains a core 1 of clay soil, filters 2 and 3 of incoherent soils forming a two-layer upper transition zone, filters 4 and 5 of incoherent soils forming a two-layer lower transition zone, upper 6 and lower 7 prisms from a stone outline and a tip 8 of non-porous soil.

The head 8 accommodates a reinforced concrete gallery 9, between the outriggers 10 of which there is a section of the free surface of the ridge 11 of the core 1. The top wall 12 of the gallery 9 is made waterproof, and the bottom wall 13 contains air ducts (hereinafter: channels) 14, which provide hydraulic communication between the gallery cavity 9 with the pore space of the stone outline of the head 8 and the bottom prism 7. The channels 14, all or part of them, are provided with shutters 15, each of which is installed at the entrance to the channel 14 from the side of the gallery cavity 9, and directly A grille 16 is installed at the exit from each channel 14. The gallery is equipped with hatches with closures: top 17 and side 18 (the latter are located at the ends of the gallery 9 and are not shown in the drawing), which can isolate the gallery cavity from direct communication with the atmosphere.

Heating gallery 9 is carried out by, for example, electroheaters (not shown) or water pipes 19.

The crest 20 of the dam, i.e. the head 8, and the bottom slope 21 of the dam, at least within the height of the head 8 is covered with a layer 22 of airtight material, such as asphalt or asphalt concrete. Such a layer 22 has a dark color, and the value of its absorption coefficient of solar radiation (solar radiation, light) is not less than 0.8. The middle part of the height of the bottom slope 21, i.e. below layer 22, it is covered with a poorly permeable layer 23 of sand and gravel soil (ASG).

The dam contains the equipment necessary for its operation in the form of fans, air ducts, pumps and a gate blocking the cavity (not shown). This equipment is able to provide forced movement of warm atmospheric air along the stone outline of the lower prism 7 through the cavity of the gallery 9 by supplying pressurized air through the hatches 17 and 18 to the gallery cavity 9 of the gallery 9 or by removing air through the hatches 17 and 18 from such a cavity .

Between the core 1 and the temperature boundary 24, which was established in the bottom prism 7 between melt and frozen soils, a highly permeable melt air duct 25 is formed. The movement of the injected air in the drawing is shown by lines 26: solid within the melt air duct 25 and dashed within a weakly permeable frostbite bottom prisms 7.

In the case of execution at the base of the core 1 lost 27, it is also advisable to make it heated.

The dam works as follows.

In the initial period of operation, the dam has a significant, 2 meters or more, excess of the level of the crest 11 of the core 1 over the normal retaining level of the NPU, the whole water pressure at which is perceived by the core 1. At a higher forced level, the upper wall 12 of the gallery 9 is included in the work, which made waterproof - its intersectional seams are sealed.

When the dam is operated in the cold season, warm water is supplied through the water pipes 19, as a result of which a positive temperature is maintained in the gallery cavity 9 year-round, which prevents freezing of the upper part of the core 1, the state of which is monitored both visually and using measuring instruments.

In the warm season, the tip 8 of the dam acquires a heat reserve due to the increased, against the usual, absorption of solar heat (solar radiation) with an asphalt layer 22 during daylight hours.

During the operation of the dam, the freezing of the bottom prism 7 can exceed the permissible limits and create a threat of freezing of the bottom filters 4 and 5. In this case, during the warm period of the year, using the previously mentioned equipment, forced movement of warm atmospheric air along the stone outline of the bottom prism 7 through the cavity of the gallery 8. As a result of this, the temperature boundary 24 is set at a safe distance from the core 1 with the formation of a highly permeable melt air duct 25, which prevents industrial opening of bottom filters 4 and 5 and, to a large extent, bottom prism 7.

When warm air is injected into the cavity of the gallery 9, the air ducts 14 direct the air into the stone outline of the head 8. Then the air is first laid with an asphalt layer 22, and then with a downward layer of ASG 23, it flows downward along the stone outline of the lower prism 7 and comes out cooled through the lower part of the lower slope 21 into the atmosphere mainly into the channel part of the dam. This is facilitated by the fact that, as a result of infiltration into the lower prism of atmospheric precipitation and negative temperatures in the rock outline, over time, the ice pores are filled with ice, which reduces the air permeability of the frozen rock outline [7].

The intensity and time of injection of warm air along the length of the dam and in its individual sections is controlled by means of shutters 15 and blocking the gate cavity.

If necessary, a vacuum can be created in the gallery cavity. In this case, the movement of warm air in the lower prism changes in the opposite direction with the entrance mainly through the lower part of the lower slope and exit to the gallery cavity.

The dam layer erected during the cold season over its entire cross section is usually frozen for several years (drawing). The supply of warm air to the lower prism accelerates the transfer of the dam from the frozen state to a more reliable melt state (except for the outer part of the lower prism). To accelerate this process through the air ducts 14 of the bottom wall 13 of the gallery 9 in the stone outline of the head 8 can be carried out the supply of warm water, for example, from water pipes 19.

The invention allows to reduce the cost of creating a dam and increase its reliability by optimizing the temperature control of a stone-earth dam in the permafrost zone by forced convection of warm air in the lower prism. However, for the successful reproduction of the proposed dam, it is necessary to carry out theoretical, theoretical, model and field studies.

The proposed technical solution can be implemented using well-known structural elements and technologies, which determines, according to the applicant, compliance with his criterion of "industrial applicability".

Information sources

1. Waterworks (in two parts). Part 1: Textbook for university students / Ed. Grishina M.M. - M .: Higher. School. 1979. S. 506-516.

2. Pekhtin V.A. On the safety of dams in the northern climatic zone. Hydraulic engineering. 2004. No. 10.

3. Patent of the Russian Federation No. 2250296, cl. ЕВВ 7/06, publ. 04/20/2005.

4. Patent of the Russian Federation No. 2309220, cl. ЕВВ 7/06, publ. 10/27/2007.

5. Patent of the Russian Federation No. 2207428, cl. ЕВВ 7/06, publ. 06/27/2003.

6. Gorokhov Mikhail Evgenievich. Regulation of the temperature regime of stone-earth dams by controlling convection of air in the lower prism. Specialty: 05.23.07 - Hydrotechnical construction. Abstract of dissertation for the degree of candidate of technical sciences. Moscow - 2011.

7. Mukhetdinov N.A., Okruzhnov S.V., Burlakov V.M. The dynamics of the temperature and humidity regime of the stone and earthen dam of the Vilyuiskaya HPP 1-2 in the operational period // Energy construction. 1999. No. 10.

Designations

1 - core

2 and 3 - top filters

4 and 5 - bottom filters

6 - mount prism

7 - grassroots prism

8 - tip

9 - gallery

10 - outrigger (galleries)

11 - core crest

12 - upper wall (galleries)

13 - bottom wall (galleries)

14 - air duct

15 - shutter

16 - grill

17 - upper hatch

18 - side hatch (not shown)

19 - water pipes

20 - dam crest

21 - downstream slope (dam)

22 - asphalt layer

23 - layer ASG

24 - temperature boundary (between thawed and frozen soils)

25 - melt air duct

26 - air movement

27 - lost.

Claims (7)

1. A stone and earth dam, the design of which is able to provide positive temperatures at the ridge and at the bottom of the dam core, erected in the northern climatic zone, contains a clay soil core, upstream and downstream transition zones from incoherent soil, upstream and downstream prisms, at least the bottom of which is made of stone outline, a head made of non-porous soil, a layer of airtight material and equipment necessary for the operation of the dam, while the head of the dam accommodates a heated concrete gallery, between the outriggers of which there is a portion of the free surface of the ridge core, and a layer of airtight material covers the dam ridge and its bottom slope, at least within the height of the head, the upper wall of the gallery is made waterproof and the lower wall contains air ducts which provide a hydraulic connection between the gallery cavity and the pore space of the stone outline of the head and the bottom prism, and the equipment can provide a force The gentle movement of warm atmospheric air along the stone outline of the lower prism through the gallery cavity. 2. The dam according to claim 1, characterized in that the layer of airtight material has a dark color, and the value of its absorption coefficient of solar radiation (solar radiation, light) is not less than 0.8. 3. The dam according to claim 1, characterized in that the gallery is equipped with hatches with closures that can isolate the gallery cavity from direct communication with the atmosphere. 4. The dam according to claim 1, characterized in that a predetermined number of air ducts from among those providing a hydraulic connection between the gallery cavity and the pore space of the stone outline are provided with gates, each of which is installed at the entrance to the air duct from the side of the gallery cavity. 5. The dam according to claim 1, characterized in that the equipment is capable of supplying air pressure to the gallery cavity. 6. The dam according to claim 1, characterized in that the equipment is capable of discharging air from the gallery cavity by discharge. 7. The dam according to claim 2, characterized in that the layer is made of asphalt or asphalt concrete.

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