Safe construction method of tunnel for pumped storage power station in inclined rock strata

Abstract

The present invention relates to the technical field of pumped-storage power stations, and specifically to a safe construction method for a pumped-storage power station tunnel in an inclined rock formation. First, the half side with a relatively high inclination is excavated from bottom to top. Before excavation, a pipe support pipe is used to support the excavated inclined rock formation. In combination with the support of a steel arch frame, a bottom plate steel frame, and hydraulic supports, the inclined rock formation can be prevented from sliding into the excavated tunnel area under its own gravity, effectively controlling the movement of the rock formation. Excavating from bottom to top is conducive to the fall of the rock formation and is also convenient for supporting the hydraulic supports. Subsequently, the half side with a relatively low inclination is excavated from top to bottom, which is conducive to ensuring the stability of the rock formation on the half side with a relatively low inclination. During excavation, the steel arch frame is supported in a timely manner, and it is ensured that the steel arch frame and the bottom plate steel frame are constructed in the excavated tunnel area in a timely manner after each layer of rock formation is excavated. This is conducive to the timely closure of the steel arch frame and the bottom plate steel frame in the excavated tunnel area, and to the timely closure of the entire section into a ring after excavation. The present invention is simple to construct and is easy to promote.

Description

Technical Field

[0001] The present invention relates to the technical field of pumped storage power stations, and in particular to a safe construction method for a tunnel of an inclined rock stratum pumped storage power station. Background Art

[0002] Pumped-storage power stations have the advantages of mature technology, fast and flexible response, large single-unit capacity, and good economy. They can effectively alleviate system peak-shaving pressure, quickly stabilize system frequency, operate in phase, and stabilize system voltage. They are the backup power source for power system accidents and can be used as a black-start power source for the power grid. They are the first choice for large-scale energy regulation.

[0003] Pumped-storage power stations are generally built in mountainous areas, using naturally formed valleys or abandoned mines after open-pit mining as water storage reservoirs. Pumped-storage power stations also include tunnel group projects to connect to water storage reservoirs. Since the tunnel group contains tunnels with various functions, the cross-sectional shapes and sizes of the tunnels are not consistent. In addition, due to the length of the tunnels and the difficulty in transporting construction equipment, it is difficult to use integrated construction equipment such as shield machines for tunnel group construction. In order to maintain long-term stability, tunnel groups need to be selected in stable rock formations as much as possible. However, rock formations are often inclined due to geological activities, and tunnel construction in inclined rock formations is easily affected by the bias pressure of the rock formations. Therefore, how to safely and efficiently construct tunnels in inclined rock formations has become a difficult problem that this field hopes to solve. Summary of the Invention

[0004] In response to the above technical problems, the present invention proposes a method for safely constructing a pumped-storage power station tunnel in an inclined rock formation. The pumped-storage power station tunnel is constructed along the inclined rock formation, comprising the following steps:

[0005] a. In the relatively high-inclination half of the tunnel, several pipe-roof pipes are constructed at intervals along the tunnel design contour line. The pipe-roof pipes are constructed along the inclined rock formation, with one pipe-roof pipe constructed for each inclined rock formation;

[0006] b. Gradually construct the relatively high-inclined side of the tunnel along its strike direction. Each construction step includes: excavating the inclined rock strata layer by layer from bottom to top, and promptly using hydraulic props to support the pipe-roof pipes in the newly excavated inclined rock strata after each layer is excavated; promptly supporting the exposed side sections of the tunnel with steel arches, and promptly supporting the exposed tunnel bottom with a bottom plate steel frame; circumferentially connecting the steel arches and bottom plate steel frames, and circumferentially connecting adjacent pipe-roof pipes with hydraulic supports on the central symmetry line of the tunnel. The hydraulic supports supported on the central symmetry line of the tunnel, along with the steel arches, bottom plate steel frames, and pipe-roof pipes, form a closed loop.

[0007] c. Lagging the relatively high-inclination half of the tunnel, and gradually constructing the relatively low-inclination half of the tunnel along the strike. Each construction step includes: excavating the inclined rock layer from top to bottom on the relatively low-inclination half of the tunnel, and promptly supporting the exposed side sections of the tunnel with steel arches after each layer of inclined rock is excavated, and connecting them to the existing steel arches on the relatively high-inclination half of the tunnel; promptly supporting the exposed bottom surface of the tunnel with bottom plate steel frames, and connecting them to the existing steel arches and bottom plate steel frames in the same ring; and removing the hydraulic supports;

[0008] d. After step c, the initial concrete is sprayed on the tunnel wall. The initial concrete spraying can cover the steel arch frame, pipe rack pipes and bottom plate steel frame. After laying the waterproof board, the secondary lining construction is carried out.

[0009] Preferably, in step a, concrete is poured into the pipe-roof pipe after the construction of the pipe-roof pipe is completed.

[0010] Preferably, in step a, the pipe-roof pipe is located in the middle of each inclined rock layer.

[0011] Preferably, in step b, a ring of support is constructed in each step and is located in the middle of the step.

[0012] Preferably, the excavation step distances of step b and step c are the same, both 1.0-1.5m.

[0013] Preferably, the construction of step c lags behind the construction of step b by 10-15 m.

[0014] Preferably, in step c, the steel arch frame and bottom plate steel frame on the half side of the tunnel with relatively low inclination are located in the same section as the steel arch frame and bottom plate steel frame on the half side of the tunnel with relatively high inclination.

[0015] Preferably, in step c, the steel arch frames adjacent along the axis in the half side of the tunnel with relatively low inclination and the bottom plate steel frames adjacent along the axis in the tunnel are respectively connected by connecting steel bars.

[0016] Preferably, in step d, step d lags behind step c by two steps, which is 2.0-3.0 m.

[0017] The key technical means and beneficial effects of the present invention are:

[0018] 1. The present invention is aimed at the pumped storage power station tunnel constructed along the strike in the inclined rock stratum. First, the half side with a relatively high inclination is excavated from the bottom up. Before excavation, the excavated inclined rock stratum is supported by pipe support pipes. Combined with the support of the steel arch frame, the bottom plate steel frame and the hydraulic pillars, the inclined rock stratum can be prevented from sliding into the excavated tunnel area due to its own gravity, and the rock stratum movement caused by the rock stratum bias can be effectively controlled. Excavation from the bottom up is conducive to the falling of the rock stratum, and the upper unexcavated rock stratum is intact and will not collapse, while facilitating the support of the hydraulic pillars.

[0019] 2. The present invention excavates the half side with relatively low inclination from top to bottom, which is beneficial to ensuring the stability of the rock layer on the half side with relatively low inclination, timely supporting the steel arch frame during excavation, and ensuring that the steel arch frame and the bottom plate steel frame are constructed in the excavated tunnel area in time after the excavation of each rock layer, which is beneficial to the timely closure of the steel arch frame and the bottom plate steel frame in the excavated tunnel area, and the timely closure of the entire section into a ring after excavation.

[0020] 3. This invention addresses the problem of inclined rock formations being susceptible to slippage into the tunnel on the side with a relatively high inclination due to bias pressure. The proposed construction method prevents this slippage by limiting the pipe-roofing pipes to the relatively high-inclination side. This solves the problem while conserving construction materials. This invention is particularly suitable for tunnels with small cross-sections where the deformation of inclined rock formations due to bias pressure is relatively small. Its simplicity of construction facilitates widespread adoption. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the expected construction location of the pumped storage power station tunnel in the inclined rock formation of the present invention;

[0022] Figure 2 This is a schematic diagram of step a of the construction of a pumped storage power station tunnel in an inclined rock formation according to the present invention;

[0023] Figure 3 This is a schematic diagram of step b of the construction of a pumped storage power station tunnel in an inclined rock formation according to the present invention. Figure 1 ;

[0024] Figure 4 This is a schematic diagram of step b of the construction of a pumped storage power station tunnel in an inclined rock formation according to the present invention. Figure 2 ;

[0025] Figure 5 This is a schematic diagram of the construction step C of the pumped storage power station tunnel in the inclined rock layer of the present invention. Figure 1 ;

[0026] Figure 6 This is a schematic diagram of the construction step C of the pumped storage power station tunnel in the inclined rock layer of the present invention. Figure 2 ;

[0027] Figure 7 This is a schematic diagram of step d, i.e., the final construction of a pumped storage power station tunnel in an inclined rock formation according to the present invention.

[0028] In the figure, 1- inclined rock layer; 2- tunnel; 3- pipe-roof pipes; 4- steel arch frame; 5- hydraulic support; 6- bottom plate steel frame; 7- excavated tunnel area; 8- tunnel lining. DETAILED DESCRIPTION

[0029] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] A safe construction method for a pumped storage power station tunnel in an inclined rock formation, such as Figure 1 As shown, the axial direction of the pumped storage power station tunnel 2 is consistent with the direction of the inclined rock layer 1. The horizontal symmetry of the tunnel 2 is constructed, including the following steps:

[0031] a. Figure 2 As shown, on the half side of the tunnel 2 with a relatively high inclination, several pipe-roof pipes 3 are constructed at intervals along the designed contour line of the tunnel 2. The pipe-roof pipes 3 are constructed along the direction of the inclined rock layer 1, that is, along the axial direction of the tunnel 2. One pipe-roof pipe 3 is constructed in the middle of each inclined rock layer 1. After the construction is completed, concrete is poured into the pipe-roof pipes 3 for reinforcement.

[0032] b. Figure 3-4 As shown, the half side of the tunnel 2 with a relatively high inclination is gradually constructed along the strike direction, and the construction length of each step is 1.0-1.5m; the construction content of each step includes: excavating the inclined rock layer 1 layer by layer from bottom to top, and promptly using hydraulic supports 5 to support the pipe-support pipes 3 in the newly excavated inclined rock layer 1 after each layer of the inclined rock layer 1 is excavated; using steel arch frames 4 to promptly support the side sections of the exposed tunnel 2, and using bottom plate steel frames 6 to promptly support the bottom surface of the exposed tunnel 2; connecting the steel arch frames 4 and the bottom plate steel frames 6 circumferentially, and connecting the adjacent pipe-support pipes 3 circumferentially; using hydraulic supports 5 to support the central symmetry line of the tunnel 2, that is, using hydraulic supports 5 to connect the center of the tunnel arch and the center of the bottom surface, and the hydraulic supports 5 supported on the central symmetry line of the tunnel 2 are closed into a ring with the steel arch frames 4, the bottom plate steel frames 6, and the pipe-support pipes 3; and preferably one ring per step, located in the middle position of the strike direction of the step;

[0033] c. The relatively high half of the inclination of the delayed tunnel 2 is 10-15m, e.g. Figure 5-6 As shown, the half side of the tunnel 2 with a relatively low inclination is gradually constructed along the strike direction, and the construction length of each step is 1.0-1.5m, which is the same as the construction step distance in step b; the construction content of each step includes: in the half side of the tunnel 2 with a relatively low inclination, excavating the inclined rock layer 1 layer by layer from top to bottom, and after each layer of the inclined rock layer 1 is excavated, the side section of the exposed tunnel 2 is promptly supported by a steel arch frame 4 and connected to the steel arch frame 4 constructed in the half side of the tunnel 2 with a relatively high inclination; the bottom surface of the exposed tunnel 2 is promptly supported by a bottom plate steel frame 6 and connected to the steel arch frame 4 and bottom plate steel frame 6 constructed in the same ring; the steel arch frame 4 and bottom plate steel frame 6 in the half side of the tunnel 2 with a relatively low inclination are located in the same section and have corresponding positions as the steel arch frame 4 and bottom plate steel frame 6 in the half side of the tunnel 2 with a relatively high inclination, so that the steel arch frame 4 and bottom plate steel frame 6 in the corresponding excavation step are closed into a ring; correspondingly, one ring is preferably formed in each step, which is located in the middle position of the strike direction of the step;

[0034] The steel arch frames 4 adjacent to each other along the axis in the half side of the tunnel 2 with a relatively low inclination and the bottom plate steel frames 6 adjacent to each other along the axis in the tunnel are connected by connecting steel bars, and the hydraulic supports 5 are removed;

[0035] d. Figure 7 As shown, the lag step c is a certain distance, such as two steps, i.e. 2.0-3.0m, and the initial concrete is sprayed on the tunnel wall. The initial concrete can cover the steel arch frame 4, the pipe scaffold pipe 3 and the bottom plate steel frame 6. After laying the waterproof board, the secondary lining construction is carried out.

[0036] The present invention is aimed at a pumped-storage power station tunnel 2 constructed along the strike in an inclined rock stratum 1. First, the half side with a relatively high inclination is excavated from bottom to top. Before excavation, a pipe-support pipe 3 is used to support the excavated inclined rock stratum 1. Part of the pipe-support pipe 3 is located in the unexcavated rock stratum and part is located in the excavated tunnel area 7. Combined with the supporting effect of the steel arch frame 4, the bottom plate steel frame 6 and the hydraulic support 5, the inclined rock stratum 1 can be prevented from sliding into the excavated tunnel area 7 under the action of its own gravity, and the rock stratum movement caused by the rock stratum bias can be effectively controlled; excavation from bottom to top is conducive to the falling of the rock stratum, and the entire upper unexcavated rock stratum is intact and will not collapse, and at the same time it is convenient to support the hydraulic support 5.

[0037] Afterwards, the present invention excavates the half side with relatively low inclination from top to bottom, which is beneficial to ensuring the stability of the rock layer on the half side with relatively low inclination, and timely supports the steel arch frame 4 during excavation, and ensures that the steel arch frame 4 and the bottom plate steel frame 6 are constructed in time in the excavated tunnel area 7 after each rock layer is excavated, which is beneficial to the timely closure of the steel arch frame 4 and the bottom plate steel frame 6 in the excavated tunnel area 7, and the timely closure of the entire section into a ring after excavation.

[0038] This invention addresses the problem of inclined rock formations being susceptible to slippage into the tunnel on the side with a relatively high inclination due to bias pressure. The proposed construction method prevents this slippage by limiting the pipe-roofing system to the relatively high-inclination side. This method solves the problem while conserving construction materials. This invention is particularly suitable for tunnels with small cross-sections and relatively small deformation of inclined rock formations due to bias pressure. Its simplicity of construction facilitates widespread adoption.

[0039] Of course, the above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above-mentioned embodiments. It should be noted that all equivalent substitutions and obvious deformation forms made by any technician familiar with this field under the guidance of this specification fall within the substantive scope of this specification and should be protected by the present invention.

Claims

1. A method for safely constructing a pumped-storage power station tunnel in an inclined rock formation, wherein the pumped-storage power station tunnel is constructed along the inclined rock formation, characterized in that: The steps include: a. In the relatively high-inclination half of the tunnel, several pipe-roof pipes are constructed at intervals along the tunnel design contour line. The pipe-roof pipes are constructed along the inclined rock formation, with one pipe-roof pipe constructed for each inclined rock formation; b. Gradually construct the relatively high-inclined side of the tunnel along its strike direction. Each construction step includes: excavating the inclined rock strata layer by layer from bottom to top, and promptly using hydraulic props to support the pipe-roof pipes in the newly excavated inclined rock strata after each layer is excavated; promptly supporting the exposed side sections of the tunnel with steel arches, and promptly supporting the exposed tunnel bottom with a bottom plate steel frame; circumferentially connecting the steel arches and bottom plate steel frames, and circumferentially connecting adjacent pipe-roof pipes with hydraulic supports on the central symmetry line of the tunnel. The hydraulic supports supported on the central symmetry line of the tunnel, along with the steel arches, bottom plate steel frames, and pipe-roof pipes, form a closed loop. c. Lagging the relatively high-inclination half of the tunnel, and gradually constructing the relatively low-inclination half of the tunnel along the strike. Each construction step includes: excavating the inclined rock layer from top to bottom on the relatively low-inclination half of the tunnel, and promptly supporting the exposed side sections of the tunnel with steel arches after each layer of inclined rock is excavated, and connecting them to the existing steel arches on the relatively high-inclination half of the tunnel; promptly supporting the exposed bottom surface of the tunnel with bottom plate steel frames, and connecting them to the existing steel arches and bottom plate steel frames in the same ring; and removing the hydraulic supports; d. After step c, the initial concrete is sprayed on the tunnel wall. The initial concrete spraying can cover the steel arch frame, pipe rack pipes and bottom plate steel frame. After laying the waterproof board, the secondary lining construction is carried out.

2. A method for safe tunnel construction of a pumped storage power station in inclined rock formations according to claim 1, characterized in that: In step a, concrete is poured into the pipe-roof pipe after the construction of the pipe-roof pipe is completed.

3. A method for safe tunnel construction of a pumped storage power station in inclined rock formations according to claim 1, characterized in that: In step a, the pipe-roof pipe is located in the middle of each inclined rock layer.

4. A method for safe tunnel construction of a pumped storage power station in inclined rock formations according to claim 1, characterized in that: In step b, one ring of support is constructed for each step and is located in the middle of the step.

5. A method for safe construction of a tunnel for a pumped-storage power station in inclined rock formations according to claim 1 or 4, characterized in that: The excavation step distances of step b and step c are the same, both 1.0-1.5m.

6. The method for safe tunnel construction of a pumped storage power station in inclined rock formations according to claim 1, characterized in that: The construction of step c lags behind the construction of step b by 10-15m.

7. The method for safe tunnel construction of a pumped storage power station in inclined rock formation according to claim 1, characterized in that: In step c, the steel arch frame and bottom plate steel frame on the half side of the tunnel with a relatively low inclination are located in the same section as the steel arch frame and bottom plate steel frame on the half side of the tunnel with a relatively high inclination.

8. The method for safe tunnel construction of a pumped storage power station in inclined rock formations according to claim 1, characterized in that: In step c, the steel arch frames adjacent to each other along the axis in the half side of the tunnel with relatively low inclination and the bottom plate steel frames adjacent to each other along the axis in the tunnel are respectively connected by connecting steel bars.

9. The method for safe tunnel construction of a pumped-storage power station in inclined rock formations according to claim 1, characterized in that: In step d, step d lags behind step c by two steps, which is 2.0-3.0m.

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