Exploration method for underground powerhouse of pumped storage power station

Abstract

The invention provides a pumped storage power station underground powerhouse exploration method. The method comprises the steps that a preset arrangement space of an underground powerhouse is obtained; a tunnel boring machine is adopted to excavate a first exploration hole from the lower reservoir of the pumped storage power station to the direction of the preset arrangement space; adopting the tunnel boring machine to excavate a horizontal second exploration hole from the tail end of the first exploration hole in the length direction of the preset arrangement space; a horizontal exploration branch hole is excavated in the middle of the second exploration hole through a drilling and blasting method, geological exploration test is conducted through the exploration branch hole, and the final arrangement space of the underground powerhouse is determined; a third exploration hole is spirally and downwards excavated from the tail end of the second exploration hole through the tunnel boring machine; a horizontal fourth exploration hole is excavated from the tail end of the third exploration hole in the length direction of the final arrangement space through the tunnel boring machine; and the tunnel boring machine is adopted to excavate a fifth exploration hole from the tail end of the fourth exploration hole to the lower reservoir. The exploration method for the underground powerhouse of the pumped storage power station is simple, convenient, high in construction efficiency and high in resource utilization rate.

Description

Technical Field

[0001] The present application relates to the technical field of exploration and excavation of pumped-storage power stations, and in particular to a method for exploring underground powerhouses in pumped-storage power stations. Background Art

[0002] Pumped storage is the use of electricity during the low load period to pump water to the upper reservoir, and then release the water stored in the upper reservoir to the lower reservoir for power generation during the peak load period, also known as energy storage power generation. It can convert the excess electricity during the low load period of the power grid into high-value electricity during the high load period of the power grid, suitable for frequency and phase modulation, can be used to stabilize the frequency and voltage of the power system, and is suitable for emergency standby, and can also improve the efficiency of thermal power plants and nuclear power plants in the power system.

[0003] At present, the exploration tunnels of underground powerhouses of pumped-storage power stations are usually constructed by manual drilling and blasting. The drilling and blasting method has low efficiency in the construction of geological exploration holes and high safety risks. Moreover, most exploration holes will be abandoned during the construction period. Some projects will use TBM (Tunnel Boring Machine) for excavation construction, but the equipment needs to be withdrawn after the completion of the main exploration hole construction. Compared with the conventional drilling and blasting method, it only improves the construction efficiency, does not adjust the exploration route, and the equipment recovery is also very troublesome.

[0004] In addition, the geological conditions of the underground project of the pumped storage power station play a decisive role in the safety and stability of the power station construction, and the accuracy of the geological survey also affects the smooth progress of the project construction. Some projects directly use the method of excavating the top arch layer of the powerhouse for geological survey. Although this method is simple, due to the complexity of geological conditions, once the location of the powerhouse changes from the initial planned location, it is necessary to re-construct the exploration hole. Not only does the previously constructed exploration hole need to be abandoned, it may also interfere with the subsequent selected powerhouse location, thereby affecting the layout of the power plant and causing a large waste of resources.

[0005] Therefore, a more efficient method for exploring underground powerhouses in pumped-storage power stations is urgently needed. Summary of the invention

[0006] In view of this, the purpose of the present application is to propose a method for exploring underground powerhouses of a pumped storage power station to solve the related problems mentioned in the background technology.

[0007] The present application provides a method for exploring an underground powerhouse of a pumped-storage power station, comprising: obtaining a preset layout space of the underground powerhouse; using a tunnel boring machine to dig a first exploration hole from the lower reservoir of the pumped-storage power station in the direction of the preset layout space, wherein the end of the first exploration hole is located above the first end of the preset layout space; using the tunnel boring machine to dig a horizontal second exploration hole from the end of the first exploration hole along the length direction of the preset layout space, wherein the end of the second exploration hole is located above the second end of the preset layout space; using a drilling and blasting method to dig a horizontal exploration branch hole in the middle of the second exploration hole, wherein the exploration branch hole is perpendicular to the second exploration hole; using the exploration branch hole to conduct a geological survey test to determine the maximum depth of the underground powerhouse. final layout space; using the tunnel boring machine to spiral downward from the end of the second exploratory hole to dig a third exploratory hole, the end of the third exploratory hole is located at the first end vault of the final layout space, and the first end of the final layout space and the first end of the preset layout space are on the same side of the underground factory building; using the tunnel boring machine to dig a horizontal fourth exploratory hole from the end of the third exploratory hole along the length direction of the final layout space, the end of the fourth exploratory hole is located at the second end vault of the final layout space, and the fourth exploratory hole is the middle guide hole of the underground factory building; using the tunnel boring machine to dig a fifth exploratory hole from the end of the fourth exploratory hole toward the lower warehouse, and the fifth exploratory hole is the ventilation hole of the underground factory building.

[0008] Furthermore, the distance between the second exploration hole and the top of the preset arrangement space is 30m to 50m.

[0009] Furthermore, the first exploration hole is arranged to be inclined downward from the head end to the tail end, and the fifth exploration hole is arranged to be inclined upward from the head end to the tail end, and the slopes of the first exploration hole, the third exploration hole and the fifth exploration hole are all less than or equal to 5%.

[0010] Further, the length of the first exploration cave is greater than the length of the fifth exploration cave, the slope of the first exploration cave is less than or equal to 1%, and the slope of the third exploration cave is less than or equal to 4%.

[0011] Furthermore, the turning radius of the first exploration cave, the third exploration cave and the fifth exploration cave are all greater than or equal to 30m.

[0012] Furthermore, the underground powerhouse is connected to a main transformer tunnel and a tail gate tunnel, and a continuous exploration tunnel formed by the second exploration tunnel, the third exploration tunnel and the fourth exploration tunnel surrounds the main transformer tunnel and the tail gate tunnel.

[0013] Furthermore, the method for exploring an underground powerhouse of a pumped-storage power station also includes: digging a connecting hole from the first exploration hole to the side wall of the underground powerhouse along the length direction, and the connecting hole and the first exploration hole are cable holes of the underground powerhouse.

[0014] Furthermore, the end of the exploration branch hole is far away from the first exploration hole.

[0015] Furthermore, the length of the exploration branch tunnel is greater than or equal to 50m.

[0016] Furthermore, the obtaining of the preset layout space of the underground power building includes: obtaining historical geological information of the location of the pumped-storage power station, and determining the preset layout space of the underground power building based on the historical geological information; the determining of the final layout space of the underground power building includes: obtaining measured geological information based on the geological survey test, and determining the final layout space of the underground power building based on the measured geological information.

[0017] As can be seen from the above, the present application provides a method for exploring an underground powerhouse of a pumped-storage power station, including: obtaining a preset layout space of an underground powerhouse; using a tunnel boring machine to dig a first exploration hole from the lower reservoir of the pumped-storage power station in the direction of the preset layout space, and the end of the first exploration hole is located above the first end of the preset layout space; using a tunnel boring machine to dig a horizontal second exploration hole from the end of the first exploration hole along the length direction of the preset layout space, and the end of the second exploration hole is located above the second end of the preset layout space; using a drilling and blasting method to dig a horizontal exploration branch hole in the middle of the second exploration hole, and the exploration branch hole is perpendicular to the second exploration hole; using the exploration branch hole to conduct ground exploration The final layout space of the underground powerhouse is determined by experiment; a tunnel boring machine is used to spiral downward from the end of the second exploratory hole to dig a third exploratory hole, the end of the third exploratory hole is located at the first end vault of the final layout space, and the first end of the final layout space and the first end of the preset layout space are on the same side of the underground powerhouse; a tunnel boring machine is used to dig a horizontal fourth exploratory hole from the end of the third exploratory hole along the length direction of the final layout space, the end of the fourth exploratory hole is located at the second end vault of the final layout space, and the fourth exploratory hole is the middle guide hole of the underground powerhouse; a tunnel boring machine is used to dig a fifth exploratory hole from the end of the fourth exploratory hole in the direction of the lower warehouse, and the fifth exploratory hole is the ventilation hole of the underground powerhouse. The exploration method forms a continuous exploration hole through a tunnel boring machine. After the relevant equipment of the tunnel boring machine enters from the first exploration hole, it can leave from the fifth exploration hole without the need for reverse retreat operation, which is convenient for equipment transfer; and the fifth exploration hole can be used as a ventilation hole for the underground powerhouse, which greatly increases the resource utilization rate. Compared with the retreat operation, it can reduce costs and save construction time; according to the preset layout space of the underground powerhouse, the first exploration hole, the second exploration hole and the exploration branch hole are excavated, and then the position of the underground powerhouse is adjusted to determine the final layout space through geological exploration tests, and the third exploration hole, the fourth exploration hole and the fifth exploration hole are excavated according to the final layout space, which can ensure the stability of the underground powerhouse. Even if the position of the powerhouse is adjusted, the previous exploration hole does not need to be abandoned, and the site selection of the new powerhouse will not be interfered with, avoiding waste of resources; the fourth exploration hole is directly used as the middle guide hole of the underground powerhouse, which is convenient for subsequent excavation of the underground powerhouse. The exploration method for the underground powerhouse of the pumped storage power station is simple and convenient, with high construction efficiency and high resource utilization rate, and can effectively assist the construction of the underground powerhouse. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of a process for exploring an underground powerhouse of a pumped-storage power station in an embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of excavation of the first exploration hole and the second exploration hole in the embodiment of the present application;

[0021] Figure 3 Schematic diagram of excavation of the third exploration cave and the fourth exploration cave in the embodiment of the present application;

[0022] Figure 4 This is a schematic diagram of the excavation of the fifth exploration cave in the embodiment of the present application;

[0023] Figure 5 This is a schematic diagram of the three-dimensional structure of the underground factory building in the embodiment of the present application;

[0024] Figure 6 This is a schematic diagram of the side structure of the underground factory building in the embodiment of the present application;

[0025] Figure 7 This is a schematic diagram of excavating a connecting hole in an embodiment of the present application;

[0026] Figure 8 A top view of the exploration and excavation route in Scheme 1 of this application;

[0027] Fig. 9 This is a schematic cross-sectional diagram of the exploration and excavation route in Scheme 1 of this application;

[0028] Fig.10 This is a top view of the exploration and excavation route in Scheme 2 of this application;

[0029] Fig.11 This is a schematic cross-sectional diagram of the exploration and excavation route in Scheme 2 of this application;

[0030] Fig.12 This is a top view of the exploration and excavation route in Scheme 3 of this application;

[0031] Fig.13 This is a schematic cross-sectional diagram of the exploration and excavation route in Scheme 3 of this application.

[0032] Figure numerals: 1. Underground plant; 2. Lower warehouse; 3. First exploration cave; 4. Second exploration cave; 4-1. Exploration branch cave; 5. Third exploration cave; 6. Fourth exploration cave; 7. Fifth exploration cave; 8. Main transformer cave; 9. Tail gate cave; 10. Connecting cave. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0034] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood by people with ordinary skills in the field to which the present application belongs. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0035] Pumped storage is the use of electricity during the low load period to pump water to the upper reservoir, and then release the water stored in the upper reservoir to the lower reservoir for power generation during the peak load period, also known as energy storage power generation. It can convert the excess electricity during the low load period of the power grid into high-value electricity during the high load period of the power grid, suitable for frequency and phase modulation, can be used to stabilize the frequency and voltage of the power system, and is suitable for emergency standby, and can also improve the efficiency of thermal power plants and nuclear power plants in the power system.

[0036] At present, the exploration tunnels of underground powerhouses of pumped-storage power stations are usually constructed by manual drilling and blasting. The drilling and blasting method has low efficiency in the construction of geological exploration holes and high safety risks. In addition, most exploration holes will be abandoned during the construction period. Some projects will use TBM (Tunnel Boring Machine) for excavation construction, but the equipment needs to be withdrawn after the completion of the main exploration hole construction. Compared with the conventional drilling and blasting method, it only improves the construction efficiency, does not adjust the exploration route, and the equipment recovery is also very troublesome.

[0037] In addition, the geological conditions of the underground project of the pumped storage power station play a decisive role in the safety and stability of the power station construction, and the accuracy of the geological survey also affects the smooth progress of the project construction. Some projects directly use the method of excavating the top arch layer of the powerhouse for geological survey. Although this method is simple, due to the complexity of geological conditions, once the location of the powerhouse changes from the initial planned location, it is necessary to re-construct the exploration hole. Not only does the previously constructed exploration hole need to be abandoned, it may also interfere with the subsequent selected powerhouse location, thereby affecting the layout of the power plant and causing a large waste of resources.

[0038] Therefore, a more efficient method for exploring underground powerhouses in pumped-storage power stations is urgently needed.

[0039] The technical solution of the present application is described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0040] Some embodiments of the present application provide a method for exploring underground powerhouses in a pumped storage power station, such as Figure 1 As shown, the following steps are included:

[0041] S1. Obtaining a preset layout space of the underground factory building 1.

[0042] The preset layout space of the underground powerhouse 1, that is, the space where the underground powerhouse 1 is planned to be arranged, can be determined by obtaining historical geological information of the location of the pumped-storage power station and based on the historical geological information. The specific determination method can be determined based on construction specifications, engineering experience or commonly used site selection methods, which will not be elaborated here.

[0043] S2. Use a tunnel boring machine to dig a first exploration hole 3 from the lower reservoir 2 of the pumped-storage power station toward the preset layout space, wherein the end of the first exploration hole 3 is located above the first end of the preset layout space.

[0044] S3. Use the tunnel boring machine to dig a horizontal second exploration hole 4 from the end of the first exploration hole 3 along the length direction of the preset arrangement space, and the end of the second exploration hole 4 is located above the second end of the preset arrangement space.

[0045] like Figure 2 and Figure 5 As shown, a first exploration hole 3 is excavated from a position near the lower warehouse 2 to the upper left end of the underground factory building 1, and then a second exploration hole 4 is excavated to the upper right end of the underground factory building 1. The second exploration hole 4 is located above the preset layout space as a whole. The purpose is to facilitate the subsequent measurement of the actual geological information at the location. If the position of the underground factory building 1 is adjusted at a later stage, it will not interfere with the site selection.

[0046] S4. A horizontal exploration branch hole 4 - 1 is excavated in the middle of the second exploration hole 4 by using a drilling and blasting method. The exploration branch hole 4 - 1 is perpendicular to the second exploration hole 4 .

[0047] S5. Conducting geological survey tests using the exploration branch tunnel 4 - 1 to determine the final layout space of the underground powerhouse 1 .

[0048] The exploration branch tunnel 4-1 is excavated by drilling and blasting to avoid the TBM from retreating; Figure 6 As shown, multiple test points can be set at intervals in the exploration branch cave 4-1 to conduct geological survey tests, and measured geological information can be obtained according to the geological survey tests. The final layout space of the underground powerhouse 1 is determined according to the measured geological information. The determination method can be the same as the method for determining the preset layout space according to the historical geological information. For the convenience of display, this application will Figures 2 to 7 The final layout space and the preset layout space of the underground factory building 1 are set to be the same space, that is, the location space of the underground factory building 1. In actual applications, the final layout space and the preset layout space can be the same or different, and there is no specific limitation.

[0049] S6. Use the tunnel boring machine to spiral downward from the end of the second exploration cave 4 to dig a third exploration cave 5, the end of the third exploration cave 5 is located at the first end vault of the final arrangement space, and the first end of the final arrangement space and the first end of the preset arrangement space are on the same side of the underground factory building 1.

[0050] S7. Use the tunnel boring machine to dig a horizontal fourth exploration hole 6 from the end of the third exploration hole 5 along the length direction of the final layout space. The end of the fourth exploration hole 6 is located at the second end vault of the final layout space. The fourth exploration hole 6 is the middle guide hole of the underground factory building 1.

[0051] like Figure 3 As shown, after the final layout space is determined, the second exploration hole 4 continues to spiral downward to dig the third exploration hole 5 to the left end of the underground factory building 1, and then the fourth exploration hole 6 is dug toward the right end of the underground factory building 1. The fourth exploration hole 6 is directly used as the middle guide hole of the underground factory building 1 to facilitate the subsequent overall excavation of the underground factory building 1.

[0052] S8. Use the tunnel boring machine to dig a fifth exploration hole 7 from the end of the fourth exploration hole 6 toward the direction of the lower storehouse 2. The fifth exploration hole 7 is a ventilation hole for the underground factory building 1.

[0053] like Figure 4 As shown, finally starting from the fourth exploration cave 6, the fifth exploration cave 7 is excavated in the direction of the lower storehouse 2. The fifth exploration cave 7 is a ventilation cave for the subsequent underground factory building 1.

[0054] The exploration method forms a continuous exploration hole through a tunnel boring machine. The relevant equipment of the tunnel boring machine can leave from the fifth exploration hole 7 after entering from the first exploration hole 3, without the need for reverse retreat operation, which is convenient for equipment transfer; and the fifth exploration hole 7 can be used as a ventilation hole for the underground factory building 1, which greatly increases the resource utilization rate. Compared with the retreat operation, it can reduce costs and save construction time; according to the preset layout space of the underground factory building 1, the first exploration hole 3, the second exploration hole 4 and the exploration branch hole 4-1 are excavated, and then the position of the underground factory building 1 is adjusted through geological survey tests to determine the final layout space, and the third exploration hole 5, the fourth exploration hole 6 and the fifth exploration hole 7 are excavated according to the final layout space, which can ensure the stability of the underground factory building 1. Even if the factory building position is adjusted, there is no need to abandon the previous exploration holes, and it will not interfere with the new factory building position, thereby avoiding waste of resources.

[0055] When selecting the entrance of the exploration flat tunnel of the underground powerhouse 1, this exploration method gives priority to the ground switch station or the ground exhaust fan room at the lower warehouse, and the excavation path is arranged in combination with the line of the ventilation tunnel as much as possible, so as to improve resource utilization and save costs. After the equipment is brought into the site, it is assembled on the exploration flat tunnel entrance platform, and the TBM equipment is excavated into the tunnel without a starting tunnel. It is excavated along the exploration flat tunnel to the right end wall above the top of the powerhouse, and then excavated along the axis of the powerhouse to the left end wall above the top of the powerhouse. Then, the exploration branch tunnel is excavated and the geological survey test is carried out to complete the location of the powerhouse; then, it spirals down from the left end wall of the top of the powerhouse to the right side of the top arch layer of the powerhouse, and then excavates through the pilot tunnel in the powerhouse along the axis of the powerhouse to the end of the ventilation tunnel, and finally excavates out of the tunnel along the axis of the ventilation tunnel. After exiting the tunnel, the equipment is disassembled and transported out.

[0056] The exploration method for the underground powerhouse of the pumped storage power station is simple and convenient, with high construction efficiency and resource utilization, and can effectively assist the construction of the underground powerhouse 1. On the basis of completing the traditional exploration flat tunnel, the feasibility study geological research experiment was carried out. After the powerhouse location was selected, the proposed top arch of the underground powerhouse 1 was further investigated. In the early stage of the project, the deep geological survey of the single cavern with the largest underground span of the project was carried out efficiently and directly, which effectively provided the most direct basis for various decisions in the early stage of the project, and also avoided the risk of abandoned exploration holes due to the displacement of the powerhouse caused by geological conditions.

[0057] In addition, the TBM construction method has the advantages of complete rock breaking and little disturbance to the surrounding rocks, which has a positive effect on the accuracy of subsequent geophysical tests; the cave excavation using it has the characteristics of good arching effect, which is of great help to the self-stabilization of the cave surrounding rock; through the data of TBM excavation footage, tool wear degree and other data, the changes in the uniaxial compressive strength of the rock can also be analyzed, which can provide a large amount of original data for exploration and flat tunnel geological survey work.

[0058] In some embodiments, the distance between the second exploration cave 4 and the top of the preset arrangement space is 30m to 50m.

[0059] The top distance between the second exploration cave 4 and the preset layout space is 30m, 35m, 40m, 45m or 50m, etc., to ensure that more effective geological data can be measured for the underground powerhouse 1 and avoid interference with the layout of caverns such as the underground powerhouse 1.

[0060] In some embodiments, the first exploration cave 3 is tilted downward from the head end to the tail end, and the fifth exploration cave 7 is tilted upward from the head end to the tail end. The slopes of the first exploration cave 3, the third exploration cave 5 and the fifth exploration cave 7 are all less than or equal to 5%.

[0061] The first exploration cave 3 is tilted downward from the head end to the tail end to avoid affecting the subsequent layout of the underground factory building 1; the fifth exploration cave 7 is tilted upward from the head end to the tail end to meet the ventilation requirements; the slopes of the first exploration cave 3, the third exploration cave 5 and the fifth exploration cave 7 are all less than or equal to 5%, for example, 1%, 2%, 3%, 4% or 5%, etc., without specific limitation, to ensure the structural stability of the exploration caves.

[0062] In some embodiments, the length of the first exploration cave 3 is greater than that of the fifth exploration cave 7, the slope of the first exploration cave 3 is less than or equal to 1%, and the slope of the third exploration cave 5 is less than or equal to 4%.

[0063] The first exploration cave 3 can be set at an angle relative to the fifth exploration cave 7, with a larger span. The head end of the first exploration cave 3 and the end of the fifth exploration cave 7 can be set close to each other, which is convenient for transferring equipment. Since the first exploration cave 3 is longer, the slope change needs to be set relatively low, for example, 1%, to ensure the stability of the exploration cave structure. Since the third exploration cave 5 is set in a spiral arrangement, the slope change can also be relatively low relative to the fifth exploration cave 7. For example, the slope of the fifth exploration cave 7 is 5%, and the slope of the third exploration cave 5 is 4%, to ensure the stability of the exploration caves.

[0064] In some embodiments, the turning radius of the first exploration cave 3, the third exploration cave 5 and the fifth exploration cave 7 are all greater than or equal to 30m.

[0065] Arc-shaped exploration caverns can be set between the first exploration cave 3 and the second exploration cave 4, between the fourth exploration cave 6 and the fifth exploration cave 7, and the third exploration cave 5 itself. The turning radius of the arc-shaped exploration cavern is greater than or equal to 30m, for example, 30m, 40m or 50m, etc., without specific limitation, to ensure that the tunnel boring machine can achieve excavation.

[0066] In some embodiments, the end of the exploration branch hole 4-1 is far away from the first exploration hole 3, and the length of the exploration branch hole 4-1 is greater than or equal to 50m.

[0067] The end of the exploration branch tunnel 4-1 is far away from the first exploration tunnel 3 to avoid interfering with the subsequent layout of the underground powerhouse 1, the main transformer tunnel 8 and the tail gate tunnel 9 to ensure stability; the length of the exploration branch tunnel 4-1 is, for example, 50m, 60m or 70m, etc., without specific limitation, to ensure that multi-point testing can be carried out to improve the reliability of the test results.

[0068] In some embodiments, the underground plant 1 is connected to a main transformer tunnel 8 and a tail gate tunnel 9, and a continuous exploration tunnel formed by the second exploration tunnel 4, the third exploration tunnel 5 and the fourth exploration tunnel 6 surrounds the main transformer tunnel 8 and the tail gate tunnel 9.

[0069] like Figure 5 and Figure 6As shown, the underground powerhouse 1 is connected to the main transformer tunnel 8 and the tail gate tunnel 9, and the third exploration tunnel 5 surrounds the main transformer tunnel 8 and the tail gate tunnel 9, so that there is no exploration tunnel above the main transformer tunnel 8 and the tail gate tunnel 9, ensuring the structural stability, and the geological survey test can also be continued along the third exploration tunnel 5 to adjust the actual layout position of the main transformer tunnel 8 and the tail gate tunnel 9.

[0070] In some embodiments, the method for exploring underground powerhouses in a pumped storage power station further includes:

[0071] S9. Dig a connecting hole 10 from the first exploration hole 3 toward the side wall of the underground factory building 1 along the length direction. The connecting hole 10 and the first exploration hole 3 are cable holes of the underground factory building 1.

[0072] like Figure 7 As shown, the drilling and blasting method can also be used to dig a connecting hole 10 at a position near the underground power building 1 in the first exploration hole 3 to connect the underground power building 1, the main transformer hole 8 and the tail gate hole 9. In this way, the connecting hole 10 and the first exploration hole 3 between the connecting hole 10 and the lower reservoir 2 can be used as cable holes to further improve resource utilization.

[0073] During the exploration and construction of the underground powerhouse of a pumped storage power station, the underground powerhouse was initially planned to be arranged in the middle, and the thickness of the overlying rock mass was about 270m-370m. The three caverns of the main powerhouse tunnel, the main transformer tunnel, and the tail gate tunnel are arranged in parallel. The excavation size of the main powerhouse tunnel is 223m×26m×56.1m, the excavation size of the main transformer tunnel is 220m×21m×23m, and the excavation size of the tail gate tunnel is 187m×8.8m×20.6m. The water diversion tunnel is bifurcated through the branch pipe and enters the plant vertically in a single-machine single-pipe manner. The traffic tunnel into the plant enters the plant from the downstream of the plant installation room vertically along the plant axis, and a ventilation tunnel is arranged at the other end; the 500kV outgoing cable is led out through a flat tunnel to the ground 500kV switch station; the exhaust tunnel adopts a flat tunnel + shaft method. Three layers of drainage corridors are arranged around the three caverns. The seepage water collected in the drainage corridors and the powerhouse eventually converges into the seepage collection well located at the bottom of the tailgate tunnel and is pumped out of the plant through the seepage drainage pump. The unit maintenance drainage is discharged out of the plant through the maintenance drainage system.

[0074] Topography: The project area is a medium-low mountain area. The highest peak near the project area is about 1078.5m. The mountains in the area are undulating and steep, and the overall terrain is high in the north and low in the south. The mountain shape is gentle at the bottom and steep at the top, with a slope of about 20°-65°, and some parts are steep cliffs. The mountain cover is shallow, and the bedrock is exposed at the steep wall; the gully bottom and river surface are covered with Quaternary loose deposits, and terraces are developed on both sides of the river. The area is crisscrossed with gullies, and gullies are developed as a whole. There are many seasonal flows in the gullies, and the water volume varies greatly due to seasonal influences.

[0075] Stratigraphic lithology: The exposed strata in the project area are mainly quartz sandstone of Changzhougou Formation (CZ) and silty shale of Chuanlinggou Formation (ChZ) of the Middle-Upper Proterozoic Changcheng System. The quartz sandstone of Changzhougou Formation (CZ) is thick to very thick, with gravel in some places. It is widely distributed along the water transmission and power generation system of the upper reservoir and the right bank of the lower reservoir. The silty shale of Chuanlinggou Formation (ChZ) is lamellar, with horizontal stratification, and is in the shape of small rods or thin sheets after weathering. It is mainly distributed on the left bank of the lower reservoir and the dam site. The Quaternary cover layer is mainly alluvial (Q2alp) gravel mixed soil, alluvial (Q4al) floating gravel, and landslide (Q4col+dl) broken (block) stone, etc., which are widely distributed in the valleys and flat areas of the project area.

[0076] Geological structure: The strata in the project area are generally monocline, with a general NW trend and a SW dip, with a mainly gentle to medium dip angle. Folds are locally developed along the water transmission line, and under their influence, the occurrence of the strata along the water transmission line has slightly changed. The main structural features in the area are mainly faults and joints (cracks).

[0077] Hydrogeology: The groundwater in the project area is buried deep, and the groundwater level generally rises with the rise of terrain. The permeability of the bedrock in the project area is mainly controlled by the fault structure and the degree of rock weathering. Generally, the permeability is strong in areas with well-developed structures and strong rock weathering, and the permeability of fresh and complete rock is weak. There are few fully strongly weathered rock masses in the project area, which are mainly exposed in the silty shale formation of the Chuanlinggou Formation. The main caverns of the factory building are all located below the groundwater level. The permeability of the slightly new quartz sandstone rock mass is mainly weak to slightly permeable, and the groundwater activity is generally weak. It is speculated that after the excavation of the cavern, water seepage and dripping will be the main factors. In the sections where faults pass or joints are developed, short-term water gushing may occur, and corresponding drainage treatment measures need to be taken.

[0078] Rock (body) physical and mechanical properties: The maximum burial depth of the water transmission system tunnel is about 443.8m. The strata along the line are mainly medium-thick to very thick layered quartz sandstone of Changzhougou Formation (CZ), and the surrounding rock is mainly weakly weathered to fresh rock. According to the test results, the average uniaxial saturated compressive strength of weakly weathered to slightly weathered surrounding rock is mainly in the range of 128.91MPa-146.17MPa, which is hard rock. The surrounding rock of the water transmission and power generation system is mainly Class III, followed by Class II, and locally Class IV-V.

[0079] The thickness of the rock mass overlying the underground powerhouse caverns is 270m-370m, and the surrounding rock conditions are basically the same as those of the water supply system tunnel. The maximum principal stress value at the underground powerhouse location is 7.05MPa-11.79MPa, which belongs to the low-medium stress level, and there is basically no risk of rock burst.

[0080] Exploration adit layout plan

[0081] TBM construction will greatly improve the excavation efficiency of underground powerhouse exploration tunnels. The first idea is to arrange the TBM excavation route separately, without taking into account the caverns on the key route of the main project, and to recycle the equipment after the construction is completed. The second idea is to take into account the caverns on the key route of the main project on the basis of the original underground powerhouse exploration tunnel. The equipment will complete the pilot tunnel excavation of the caverns on the key route (such as ventilation tunnels), and then retreat or continue to excavate to drive out. Combining the above ideas and the hub layout of this project, four TBM excavation plans for underground powerhouse exploration tunnels are initially proposed:

[0082] Option 1: The underground powerhouse exploration tunnel is arranged separately and does not overlap with the permanent cavern line.

[0083] Option 2: The underground powerhouse exploration tunnel is designed to coincide with the ventilation tunnel and the guide tunnel on the first floor of the powerhouse.

[0084] Option three: The underground powerhouse exploration tunnel is designed to coincide with some ventilation tunnels, some traffic tunnels and the exploration branch tunnels along the powerhouse axis.

[0085] Option 4: The underground powerhouse exploration tunnel and the ventilation tunnel are designed to coincide with the center guide tunnel on the first floor of the powerhouse (i.e. the core option of this application).

[0086] The specific arrangements of the four schemes are as follows:

[0087] Plan 1 layout: Figure 8 and Fig. 9 As shown in the figure, the entrance of the powerhouse exploration cave is located on the right bank of the lower reservoir area. The horizontal tunnel is located between the tailwater tunnel and the ventilation tunnel, with a strike of NE8°. The total length of the horizontal tunnel is about 1697m, the entrance elevation is 320m, the bottom plate slope is controlled within 5‰, and the terminal elevation is 328m, which is about 56m higher than the top arch of the powerhouse. A branch tunnel is planned to be arranged along the axis of the powerhouse inside the powerhouse exploration cave, with a length of about 360m, forming a cross exploration area. From the profile of the powerhouse exploration cave, it can be seen that the overburden of the first 200m of the exploration cave is relatively thin, while the rest of the section is strong, and the entrance is located on the slope of a hill. In this scheme, after the TBM excavates the main cave of 1697m, it will continue to excavate forward for about 200m to reserve a safe blasting distance for the drilling and blasting construction of the exploration branch tunnel (358m) of the powerhouse axis. After the construction of the exploration branch tunnel of the powerhouse axis is completed, the TBM equipment will be recovered by retreating.

[0088] Scheme 2 layout: Fig.10 and Fig.11 As shown in the figure, the underground powerhouse exploration tunnel was initially planned to be excavated along the axis of the ventilation tunnel, passing through the pilot tunnel on the first floor of the powerhouse, and continuing to excavate forward for about 200m to reserve a safe blasting distance for the drilling and blasting construction of the high-pressure branch pipe exploration tunnel (261m). After the construction of the high-pressure branch pipe exploration tunnel is completed, the TBM equipment will be recovered by retreating.

[0089] Plan 3 layout: Fig.12 and Fig.13 As shown, the underground powerhouse exploration tunnel begins to branch at the pile number 1+189 along the axis of the traffic tunnel, and then the tunnel section starts to slope from the bifurcation point, and finally reaches 35m above the top arch of the powerhouse, and moves along the plant axis. It starts to descend 50m outside the left end wall of the powerhouse, and drives towards the ventilation tunnel. At the pile number of the ventilation tunnel of about 1+060.0m, it merges into the axis of the ventilation tunnel and finally drives out along the tunnel line of the ventilation tunnel. The total length of the pilot tunnel in this scheme is about 3415m. In addition, in order to better explore the surrounding rock conditions at the location of the high-pressure branch pipe, a branch tunnel of about 261m long (drilling and blasting method) is arranged between the 3# and 4# units perpendicular to the axis of the powerhouse, forming a cross survey area.

[0090] Scheme 4: Figures 2 to 4 As shown, it is implemented in 3 steps. Step 1 (downhill, average slope 0.8%): excavate along the flat tunnel to the left end wall of the powerhouse, the end elevation is 302.75m, about 33m higher than the top arch of the powerhouse. According to the actual geological conditions revealed by the cave exploration, the position of the cave group is adjusted accordingly, and the subsequent tunnel line of the cave exploration is adjusted accordingly. Step 2 (downhill, average slope 3.6%): from the elevation of 302.75m, circle downward, pass through the pilot tunnel in the powerhouse in the middle, and excavate to the end of the ventilation tunnel, the elevation is 262.00m. Step 3 (pile number D2+994~D4+3960 uphill, average slope 4.7%; pile number D4+396~D4+546 downhill, slope 5%): excavate along the axis of the ventilation tunnel to the fork of the branch tunnel, and excavate along the branch tunnel to the exit elevation of 320.0m, and the construction is completed.

[0091] From the analysis of the layout of each scheme, the exploration holes at the plant location of Scheme 1, Scheme 3, and Scheme 4 are all 30m above the top arch elevation, which is conducive to fully identifying the geological conditions of the plant area, and can flexibly adjust the location and axis direction of the plant in the event of major changes in geological conditions. In addition, from the analysis of the overlap range of the pilot tunnel and the main cavern, as the exploration hole gradually approaches the plant area, the axis and position of the plant may be adjusted. At this time, the pilot tunnels of some ventilation tunnels in Scheme 2 and Scheme 3 that are penetrated in advance will not be used, and there is also the possibility that some tunnel sections will affect the top arch and side walls of the plant. Scheme 4 can adjust the line through the second leg so that all the pilot tunnels are located on the axis of the pilot tunnel in the excavation of the ventilation tunnel and the first floor of the plant. Therefore, from the analysis of the layout of the scheme, Scheme 1 and Scheme 4 are better than Scheme 2 and Scheme 3.

[0092] From the perspective of the main construction period of the project, due to the different overlaps between the various schemes and the permanent caverns on the key lines, the main construction period saved by each scheme is different. The main construction period saved by each scheme is 0 months, 8.7 months, 5.2 months, and 8.9 months respectively. From the analysis of the saved construction period, Scheme 2 and Scheme 4 are more advantageous.

[0093] In summary, in order to fully identify the geological conditions of the plant area and place as many TBM excavation routes as possible in the caverns on the key routes, save construction time for the main project, and improve equipment utilization efficiency, Scheme 4 has more obvious advantages as a TBM excavation route. It takes into account the construction of the ventilation tunnel and the pilot tunnel in the plant, which not only saves the initial investment time of the project, but also saves about 9 months for the main project, creating favorable conditions for the first machine to generate electricity in advance.

[0094] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0095] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present application difficult to understand, the device can be shown in the form of a block diagram, so as to avoid making the embodiments of the present application difficult to understand, and this also takes into account the following fact, that is, the details of the implementation method of these block diagram devices are highly dependent on the platform to be implemented in the embodiments of the present application (that is, these details should be fully within the scope of understanding of those skilled in the art). In the case of elaborating specific details to describe the exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered to be illustrative rather than restrictive.

[0096] Although the present application has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0097] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A method for exploring underground powerhouses of a pumped storage power station, characterized in that: include: Obtaining a preset layout space of the underground plant; A tunnel boring machine is used to dig a first exploration hole from the lower reservoir of the pumped storage power station toward the preset layout space, wherein the end of the first exploration hole is located above the first end of the preset layout space; Using the tunnel boring machine to dig a horizontal second exploration hole from the end of the first exploration hole along the length direction of the preset arrangement space, the end of the second exploration hole is located above the second end of the preset arrangement space; Using a drilling and blasting method to dig a horizontal branch exploration hole in the middle of the second exploration hole, wherein the branch exploration hole is perpendicular to the second exploration hole; Conducting geological survey tests using the exploration branch tunnel to determine the final layout space of the underground powerhouse; The tunnel boring machine is used to spiral downward from the end of the second exploration hole to dig a third exploration hole, wherein the end of the third exploration hole is located at the first end vault of the final arrangement space, and the first end of the final arrangement space and the first end of the preset arrangement space are on the same side of the underground factory building; The tunnel boring machine is used to dig a horizontal fourth exploration hole from the end of the third exploration hole along the length direction of the final layout space, the end of the fourth exploration hole is located at the second end vault of the final layout space, and the fourth exploration hole is the middle guide hole of the underground factory building; The tunnel boring machine is used to dig a fifth exploration hole from the end of the fourth exploration hole toward the direction of the lower storehouse, and the fifth exploration hole is a ventilation hole of the underground factory building.

2. The method for exploring underground powerhouses of a pumped storage power station according to claim 1, characterized in that: The distance between the second exploration hole and the top of the preset arrangement space is 30m to 50m.

3. The method for exploring underground powerhouses of a pumped storage power station according to claim 1, characterized in that: The first exploration hole is arranged to be inclined downward from the head end to the tail end, and the fifth exploration hole is arranged to be inclined upward from the head end to the tail end. The slopes of the first exploration hole, the third exploration hole and the fifth exploration hole are all less than or equal to 5%.

4. The method for exploring underground powerhouses of a pumped storage power station according to claim 3, characterized in that: The length of the first exploration cave is greater than that of the fifth exploration cave, the slope of the first exploration cave is less than or equal to 1%, and the slope of the third exploration cave is less than or equal to 4%.

5. The method for exploring underground powerhouses of a pumped storage power station according to claim 1, characterized in that: The turning radius of the first exploration cave, the third exploration cave and the fifth exploration cave are all greater than or equal to 30m.

6. The method for exploring underground powerhouses of a pumped storage power station according to claim 1, characterized in that: The underground powerhouse is connected with a main transformer tunnel and a tail gate tunnel, and a continuous exploration tunnel formed by the second exploration tunnel, the third exploration tunnel and the fourth exploration tunnel surrounds the main transformer tunnel and the tail gate tunnel.

7. The method for exploring underground powerhouses of a pumped storage power station according to claim 1, characterized in that: Also includes: A connecting hole is excavated from the first exploration hole toward the side wall of the underground factory building along the length direction, and the connecting hole and the first exploration hole serve as cable holes of the underground factory building.

8. The method for exploring underground powerhouses of a pumped storage power station according to claim 1, characterized in that: The end of the exploration branch hole is far away from the first exploration hole.

9. The method for exploring underground powerhouses of a pumped storage power station according to claim 1, characterized in that: The length of the exploration branch tunnel is greater than or equal to 50m.

10. The method for exploring underground powerhouses of a pumped storage power station according to claim 1, characterized in that: The obtaining of the preset layout space of the underground powerhouse includes: obtaining historical geological information of the location of the pumped-storage power station, and determining the preset layout space of the underground powerhouse according to the historical geological information; The determining of the final layout space of the underground powerhouse includes: obtaining measured geological information according to the geological survey test, and determining the final layout space of the underground powerhouse according to the measured geological information.

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