Multi-point distributed underground engineering structure of pumped storage power station in karst area and design method

Abstract

The invention provides a karst area pumped storage power station multi-point distributed underground engineering structure and a design method, and relates to the technical field of water conservancy and hydropower engineering.The karst area pumped storage power station multi-point distributed underground engineering structure comprises an upper reservoir and a lower reservoir which are arranged on a mountain in a high-low staggered mode, and the upper reservoir and the lower reservoir are connected through a water conveying tunnel; power plants of the pumped storage power station are divided according to functions and distributed in a mountain between an upper reservoir and a lower reservoir, each power plant comprises a plurality of generator sets, the generator sets are arranged on a water delivery tunnel and connected with a traffic hole through a shaft, and the traffic hole is connected with a control center and serves as an entrance and exit of the power plants. A multi-point distributed layout strategy is adopted, the power plant is subdivided into a plurality of small-size spaces, and therefore arrangement flexibility is achieved, and the design is beneficial for avoiding unfavorable geological conditions such as karst and karst caves; not only are the difficulty and the work amount of anti-seepage treatment reduced, but also the project investment is saved.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and hydropower engineering, and in particular to a multi-point distributed underground engineering structure of a pumped storage power station in a karst area and a design method thereof. Background Art

[0002] A pumped-storage power station is usually composed of four parts: the upper reservoir, the water diversion system, the power plant system, and the lower reservoir. Among them, the power plant system is the core of the pumped-storage power station and constitutes the central brain of the pumped-storage power station.

[0003] Most of the pumped-storage power stations currently under construction or completed use underground power plant systems. The location of the power plant is greatly affected by geological conditions and construction conditions. The power plant is preferably designed in a rock formation with relatively complete bedrock and stable surrounding rock. However, in the current design of pumped-storage power plants, the underground power plant system often occupies a large space. For example, for a pumped-storage power plant with an installed capacity of about 1.2 million kWa, the power plant system occupies a space of about 500 meters long, 200 meters wide, and 100 meters high. However, the range of underground rock formations with complete and stable surrounding rock is limited. The use of existing underground power plant design types often requires the addition of more engineering measures, resulting in increased project investment.

[0004] The design of the underground power plant of a pumped-storage power station is usually located about 100m below the normal water level of the lower reservoir. On the one hand, there is a risk of water leakage in the lower reservoir; on the other hand, the construction period is long. In order for the underground power plant to meet the construction conditions, it is often necessary to build a construction traffic tunnel about 2.0km long from the ground to reach the underground power plant, resulting in a long construction period of the pumped-storage power station and a large increase in investment.

[0005] The design of pumped storage power stations in southwest my country, such as Guizhou Province, Sichuan Province, Yunnan Province, Guangxi Zhuang Autonomous Region, etc., is greatly affected by the development of geological karst, especially when designing pumped storage power stations in the built lower reservoir, there are karst pipelines, cracks and faults of reservoir water, the anti-seepage design of underground power plant is difficult, the construction safety risk is high, and the project investment is large. For example, when designing a pumped storage power station in Guizhou Province, the lower reservoir is located in the reservoir area of ​​the built large hydropower station, the underground power plant system is located on the left bank of the reservoir area, about 800 meters away from the water surface of the reservoir area, the elevation of the underground power plant installation room is about 100 meters below the normal water level of the reservoir, and the access tunnel to the power plant installation room is about 2.0 km long. According to the geological revelation of the underground power plant flat tunnel, there are large karst caves and karst cavities in the optional underground power plant layout area, and there are karst pipelines connected to the reservoir water. The construction safety risks of underground power plants are extremely high, the construction period is long, the design is difficult, especially the anti-seepage design of underground power plants is difficult, the safety risks during the operation and maintenance period are high, and the project investment is large. Summary of the invention

[0006] The present invention provides a multi-point distributed underground powerhouse design method for pumped-storage power stations in karst areas, which is mainly used to solve the problems of building pumped-storage power stations in karst-developed areas, such as stable cavern surrounding rock, great difficulty in preventing reservoir water leakage, high construction safety risk, long construction period and large project investment. The present invention is particularly suitable for the design and construction of underground powerhouse systems for pumped-storage power stations, which require a large spatial range for the layout of underground powerhouse systems, have a limited range of stable cavern surrounding rock, have developed geological karst, and are connected between karst and reservoir water.

[0007] The present invention provides the following technical solutions to achieve the above objectives:

[0008] A multi-point distributed design method for a pumped-storage power station in a karst area, comprising an upper reservoir and a lower reservoir arranged at different heights on a mountain, the upper reservoir and the lower reservoir being connected by a water transfer tunnel, and characterized in that a power plant of the pumped-storage power station is functionally zoned and dispersedly arranged in the mountain between the upper reservoir and the lower reservoir, the power plant comprises a plurality of generator rooms, the generator rooms are arranged on the water transfer tunnel, the generator rooms are connected to a traffic tunnel through a shaft, the traffic tunnel is connected to a control center and is arranged as an entrance and exit of the power plant.

[0009] Furthermore, the water transfer tunnel is arranged in a stepped manner according to the height difference between the upper reservoir and the lower reservoir, and the generator rooms are all arranged on the lowest level lower section of the water transfer tunnel.

[0010] Furthermore, the generator room is connected to the control center via a cable.

[0011] Furthermore, the control center and the traffic tunnel are arranged at elevations higher than the highest operating water level of the lower reservoir.

[0012] Furthermore, a plurality of generator rooms are arranged corresponding to the one wellbore.

[0013] Furthermore, the cross section of the wellbore is arranged in a circular cross section.

[0014] Furthermore, the cross section of the wellbore is arranged in a circular cross section.

[0015] A design method for a multi-point distributed underground engineering structure of a pumped storage power station in a karst area comprises the following steps:

[0016] Step 1: Divide the power plant building into generator room, control center, traffic tunnel and shaft according to function, and conduct geological survey of the proposed dam area;

[0017] Step 2: According to the geological survey results, select an area with stable and complete surrounding rock and relatively undeveloped karst as the layout area of ​​the generator room;

[0018] Step 3: Design the route of the water conveyance tunnel according to the layout position of the generator room. The water conveyance tunnel adopts a layout mode in which one water conveyance tunnel is corresponding to one generator room or one water conveyance tunnel is corresponding to several generator rooms;

[0019] Step 4: According to the geological conditions of the generator room layout area, one generator room is arranged for one wellbore or several generator rooms are arranged for one wellbore;

[0020] Step five, arrange the control center and traffic tunnel according to the layout position of the generator room, with the control center close to the generator room and the traffic tunnel connected to the generator room and the control center, so as to reduce the cable laying length.

[0021] Beneficial Effects

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention adopts a multi-point distributed layout strategy to subdivide the power plant into several smaller spaces, thereby achieving flexibility in layout. This design helps to avoid unfavorable geological areas such as karst and caves; it not only reduces the difficulty and engineering workload of anti-seepage treatment, but also saves engineering investment. At the same time, this design is also conducive to ensuring the stability of the surrounding rock of the underground cavern.

[0024] 2. The present invention can effectively avoid the safety risks of personnel and equipment caused by reservoir water level leakage during construction and operation by setting the control center and the traffic tunnel above the highest water level of the lower reservoir.

[0025] 3. Compared with the current design of underground power plant traffic tunnels, the total length of the traffic tunnel of the present invention can be reduced by more than 50%. When designing the excavation and support of the control center and the traffic tunnel, the anti-seepage treatment engineering measures can be simplified, thereby reducing the project investment by more than 70%. At the same time, the length of the traffic tunnel is shortened, so that the generator room can be constructed as early as possible; through the division of spatial areas, each generator room is relatively independent, so that multiple generator rooms can be constructed at the same time, greatly shortening the construction period. Under the same installed capacity conditions, compared with the existing underground power plant design, its total construction period can be shortened by more than 6 months.

[0026] 3. The present invention sets the cross section of the wellbore to be circular, fully utilizing the self-bearing capacity of the soil, converting the pressure of the soil into annular pressure, reducing stress concentration, and thus improving the overall stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below only relate to some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

[0028] Figure 1 This is the plan layout of the power plant of the present invention;

[0029] Figure 2 The shaft structure of the present invention is arranged Figure 1 ;

[0030] Figure 3 The shaft structure of the present invention is arranged Figure 2 .

[0031] Figure numerals: 1-lower reservoir, 2-mountain, 3-upper reservoir, 4-water diversion tunnel, 5-karst cave with poor geological body, 6-anti-seepage curtain, 7-generator set, 8-control center, 9-traffic tunnel, 10-drainage hole, 11-elevator, 12-grouting gallery, 13-wellbore, 14-circular ladder. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0033] It should be noted that in the present invention: the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or apparatuses; the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like are based on the directions or positional relationships shown in the drawings. These The terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation; the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence; the terms "install", "set", "provided with", "connected", "connected", "sleeved", etc. should be understood in a broad sense; for example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. In addition, some terms can be used to express other meanings in addition to indicating orientation or positional relationships. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0034] Example 1. A multi-point distributed underground engineering structure of a pumped storage power station in a karst area, with reference to the structure Figure 1 and 2 , including an upper reservoir 3 and a lower reservoir 1 arranged at different heights on a mountain 2, the upper reservoir 3 and the lower reservoir 1 are connected by a water transfer tunnel 4, the power plant of the pumped storage power station is divided into functional areas and dispersedly arranged in the mountain 2 between the upper reservoir 3 and the lower reservoir 1, the power plant includes a number of generator rooms 7, the generator rooms 7 are arranged on the water transfer tunnel 4, the generator rooms 7 are connected to the traffic tunnel 9 through a shaft 13, the traffic tunnel 9 is connected to the control center 8 and is set as the entrance and exit of the power plant. The control center 8 can select a suitable location according to the actual situation of the project, and can be set inside or outside the mountain 2. Setting it outside the mountain 2 can reduce the amount of excavation engineering.

[0035] The water conveyance tunnel 4 is arranged in a stepped manner according to the height difference between the upper reservoir and the lower reservoir, and the generator room 7 is arranged on the lowest level lower section of the water conveyance tunnel 4. The generator set 7 is arranged on the lowest level water conveyance tunnel 4 to obtain the maximum water level difference and ensure the power generation power of the generator set 7.

[0036] The generator room 7 is connected to the control center 8 via a cable. The cable connection is provided to facilitate the control center 8 to monitor the generator room 7.

[0037] The control center 8 and the traffic tunnel 9 are arranged at elevations higher than the highest operating water level of the lower reservoir 1. Placing the control center 8 and the traffic tunnel 9 above the highest water level of the lower reservoir 1 can effectively avoid the safety risks of personnel and equipment caused by reservoir water level leakage during construction and operation.

[0038] The shaft 13 is provided with a plurality of generator sets 7. Figure 2 , one generator set 7 is set for each shaft 13. If four generator sets 7 are designed, four shafts 13 need to be designed, and each shaft 13 is independent of each other. Each shaft 13 is designed with anti-seepage and drainage respectively, and the anti-seepage and drainage designs are arranged around the shaft 13; an elevator and a manual ladder are set in each shaft 13, which serve as the operation passage of the generator room and the escape passage of personnel respectively. The cross-section of the shaft 13 is set in a circular shape. By setting the cross-section of the shaft 13 to a circular shape, the self-bearing capacity of the soil is fully utilized, the pressure of the soil is converted into annular pressure, and the stress concentration is reduced, thereby improving the overall stability.

[0039] Example 2. In the implementation process of Example 1, each generator set 7 is relatively independent, the safety of personnel and equipment is high, and the unit is easy to hoist. However, the cavern occupies a large geological area, the probability of encountering karst caves is high, the shaft excavation and anti-seepage curtain engineering is large, and a large number of elevators need to be installed, and the project investment is large. Therefore, this embodiment adjusts the setting mode of the shaft 13 on the basis of Example 1, and the structure is referenced. Figure 3 , a connection method is adopted in which a plurality of generator sets 7 are correspondingly arranged in one shaft 13. The number and location of the generator sets 7 are determined according to the layout position and geological conditions of the generator sets 7, so as to ensure that one shaft 13 radiates a plurality of generator sets 7 through the tunnel. Compared with Example 1, the overall space occupied by the cavern in the geological area is smaller, the probability of encountering karst caves is small, the amount of shaft excavation and anti-seepage curtain engineering is relatively small, fewer elevators are installed, and the engineering investment is relatively small.

[0040] A design method for a multi-point distributed underground engineering structure of a pumped storage power station in a karst area comprises the following steps:

[0041] Step 1: divide the power plant into generator room 7, control center 8, traffic tunnel 9 and shaft 13 according to function, and conduct geological survey on the proposed dam area;

[0042] Step 2: According to the geological survey results, select an area where the surrounding rock is stable and complete and the karst is relatively undeveloped as the layout area of ​​the generator room 7;

[0043] Step three, design the route of the water conveyance tunnel 4 according to the layout position of the generator room 7. The water conveyance tunnel 4 adopts a layout mode in which one water conveyance tunnel 4 corresponds to one generator room 7 or one water conveyance tunnel 4 corresponds to several generator rooms 7; the specific layout is determined based on comprehensive economic and technical comparison.

[0044] Step 4, according to the geological conditions of the layout area of ​​the generator room 7, adopt an arrangement mode in which one generator room 7 is arranged for one shaft 13 or several generator rooms 7 are arranged for one shaft 13; the specific arrangement mode is determined based on comprehensive economic and technical comparison.

[0045] Step five, arrange the control center 8 and the traffic tunnel 9 according to the layout position of the generator room 7, with the control center 8 close to the generator room 7 and the traffic tunnel 9 interconnected with the generator room 7 and the control center 8 as the principle, so as to reduce the cable laying length; the traffic tunnel is interconnected with the control center and the generator room, and the design of the traffic tunnel must fully consider the transportation needs during the construction period and the convenience of traffic during the later operation period.

[0046] The present invention has been tried out in actual projects. When a pumped storage power station in the southwest region was designed, the pumped storage power station used the reservoir area of ​​a large hydropower station as the lower reservoir. The underground power plant was located on the left bank of the reservoir area, and the installation elevation of its unit was about 100 meters lower than the highest water level of the reservoir. The geological exploration of the underground power plant revealed that the karst and faults on the left bank of the reservoir area were developed, mainly manifested as large centralized caves. The caves were connected to the reservoir water, but the surrounding rock formations between the caves were relatively complete. The existing underground power plant layout design required a large space size, which was difficult to avoid caves, and the probability of encountering caves was high. The anti-seepage design of the underground power plant was difficult, the construction safety risk was extremely high, and the project investment was large.

[0047] The pumped-storage power station adopts the multi-point distributed underground plant design method provided by the present invention. The underground power plant is divided into multiple spaces for layout design. Each space is small in size and flexible in layout, effectively avoiding unfavorable geological conditions such as underground karst caves and faults on the left bank, thereby optimizing a large number of cavern excavation support and anti-seepage treatment projects. The present invention is used to arrange and design important facilities such as the power plant control center, plant access tunnel, and main transformer room in the mountain on the left bank of the reservoir, all of which are higher than the highest water level of the reservoir. The length of the plant access tunnel is shortened from the original design of 2km to 1.2km, and the construction period is shortened by about 6 months. At the same time, safety risk accidents such as reservoir water leakage in the underground power plant are avoided during the construction and operation periods, ensuring the safety of personnel and equipment.

[0048] Obviously, the above is only a part of the embodiments of the present invention, not all of the embodiments. The above embodiments are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and variations. Any combination, modification, equivalent replacement, improvement and all other embodiments that can be made by those of ordinary skill in the art within the spirit and principle of the present invention should be within the protection scope of the present invention.

Claims

1. A multi-point distributed underground engineering structure of a pumped storage power station in a karst area, comprising an upper reservoir (3) and a lower reservoir (1) arranged in a staggered manner on a mountain (2), the upper reservoir (3) and the lower reservoir (1) being connected via a water transfer tunnel (4), characterized in that: The power plant of the pumped storage power station is divided into functional areas and dispersedly arranged in a mountain (2) between an upper reservoir (3) and a lower reservoir (1). The power plant includes a plurality of generator rooms (7). The generator rooms (7) are arranged on a water conveyance tunnel (4). The generator rooms (7) are connected to a traffic tunnel (9) through a shaft (13). The traffic tunnel (9) is connected to a control center (8) and is provided as an entrance and exit of the power plant.

2. The multi-point distributed underground engineering structure of a pumped storage power station in karst areas according to claim 1 is characterized by: The water conveyance tunnel (4) is arranged in a stepped manner according to the height difference between the upper reservoir and the lower reservoir, and the generator rooms (7) are all arranged on the lowest level lower section of the water conveyance tunnel (4).

3. The multi-point distributed underground engineering structure of a pumped storage power station in karst areas according to claim 1 is characterized by: The generator room (7) is connected to the control center (8) via a cable.

4. The multi-point distributed underground engineering structure of a pumped storage power station in karst areas according to claim 1 is characterized by: The control center (8) and the traffic tunnel (9) are both arranged at elevations higher than the highest operating water level of the lower reservoir (1).

5. The multi-point distributed underground engineering structure of a pumped storage power station in karst areas according to claim 1 is characterized by: A plurality of generator rooms (7) are correspondingly arranged in the one shaft (13).

6. The multi-point distributed underground engineering structure of a pumped storage power station in a karst area according to any one of claims 1 and 5, characterized in that: The cross section of the wellbore (13) is arranged in a circular cross section.

7. The design method of multi-point distributed underground engineering structure of a pumped storage power station in karst areas according to claim 1 is characterized by: The following steps are involved: Step 1: divide the power plant into the generator room (7), control center (8), traffic tunnel (9) and shaft (13) according to their functions, and conduct geological survey on the proposed dam area; Step 2: According to the geological survey results, select an area where the surrounding rock is stable and complete and the karst is relatively undeveloped as the layout area of ​​the generator room (7); Step 3, designing the route of the water conveyance tunnel (4) according to the arrangement position of the generator room (7), wherein the water conveyance tunnel (4) is arranged in a manner that one water conveyance tunnel (4) is provided with one generator room (7) or one water conveyance tunnel (4) is provided with several generator rooms (7); Step 4, according to the geological conditions of the area where the generator room (7) is arranged, a layout method is adopted in which one generator room (7) is arranged for one shaft (13) or a plurality of generator rooms (7) are arranged for one shaft (13); Step 5, the control center (8) and the traffic tunnel (9) are arranged according to the layout position of the generator room (7), with the control center (8) being close to the generator room (7), and the traffic tunnel (9) being interconnected with the generator room (7) and the control center (8), so as to reduce the cable laying length.

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