Construction method of open-pit mine pumped storage power station considering influence of goaf

Abstract

The present application relates to the field of abandoned mine reutilization and pumped storage, and particularly relates to a construction method of open-pit mine pumped storage power station considering the influence of goaf; the method comprises the following steps: selecting a certain thick hard rock layer above the water-conducting fractured zone, constructing an auxiliary platform and a grouting station at the intersection of the rock layer and the open-pit mine slope; constructing an auxiliary flat tunnel, a tail water tunnel and a mechanical and electrical chamber from the auxiliary platform; simultaneously excavating an upper water diversion tunnel and a lower water diversion tunnel from top to bottom, and continuously constructing an auxiliary flat tunnel towards the direction of the mine shaft, and constructing a grouting borehole from the auxiliary flat tunnel to the caving zone and the water-conducting fractured zone and grouting; constructing an upper reservoir based on the collapse pit, and constructing a lower reservoir based on the lower part of the open-pit mine; connecting the upper water diversion tunnel and the lower water diversion tunnel through the auxiliary flat tunnel between the upper water diversion tunnel and the lower water diversion tunnel as a transition water diversion tunnel, and constructing a pressure regulating chamber in the transition water diversion tunnel. The present application can realize multi-process parallel construction, greatly save the construction period and reduce the construction cost, and can ensure the stability of the upper reservoir.

Description

Technical Field

[0001] The present invention relates to the fields of abandoned mine reuse and pumped storage, and in particular to a construction method of an open-pit mine pumped storage power station taking into account the influence of goaf areas. Background Art

[0002] Mining methods for coal and other mineral seams include open-pit mining and underground mining. When the ore seam is shallow, thick, or numerous, open-pit mining involves stripping away the soil and rock covering the seam before mining. When the coal seam is deeper, stripping away the soil and rock is very costly, so underground mining typically involves constructing a vertical or inclined shaft to reach the seam, then deploying tunnels within the seam before mining. Depending on the mining method, open-pit mining can result in a large pit that gradually decreases in size from top to bottom. Underground mining can cause the overlying rock layer to collapse, forming a sinkhole on the surface.

[0003] Pumped-storage hydropower stations pump water from lower reservoirs to higher reservoirs to store energy, generating electricity when needed by the power system. They utilize excess electricity from the power system to pump water from the lower reservoir to the upper reservoir, converting it into stored water potential energy. This energy is then converted into electricity when needed. Pumped-storage hydropower stations effectively store electricity, thereby improving the operational efficiency and resource utilization of thermal, nuclear, and wind power generation in the power system, effectively regulating the dynamic balance between production, supply, and use.

[0004] The construction of pumped-storage power plants using abandoned mine goafs, roadways, and open pits as water storage reservoirs is a current research hotspot. However, existing research is largely limited to pumped-storage power plants based on open-pit mining or underground mining goafs and roadways. However, some mines, both domestically and internationally, utilize a combination of open-pit and underground mining, or have close proximity between open-pit and underground mines, such as the Xinling Coal Mine, the Haizhou Coal Mine in Fuxin, and the Jianlong Iron Mine. Under these circumstances, the question of how to comprehensively consider the abandoned mines created by both mining methods when selecting the sites for various pumped-storage power plant components and how to rapidly and concurrently construct these power plants has become a pressing technical challenge in this field. Summary of the Invention

[0005] In response to the above technical problems, the present invention proposes a construction method for an open-pit mine pumped-storage power station that takes into account the influence of mined-out areas. The upper reservoir is constructed based on the collapse pit formed by underground mining, and the lower reservoir is constructed based on the open-pit mine pit. The mined-out area below the upper reservoir is grouting-filled and reinforced, which greatly reduces the cost and construction period of the water storage reservoir construction and can ensure the stability of the water storage reservoir. At the same time, auxiliary flat tunnels are constructed as space for grouting reinforcement of the mined-out area and construction of water tunnels, which can realize parallel construction of multiple tasks.

[0006] Specifically, the construction method of an open-pit mine pumped storage power station taking into account the influence of goaf of the present invention includes the following steps:

[0007] a. Determine the height of the water-conducting fracture zone after underground coal seam mining and the location of all thick hard rock layers above the water-conducting fracture zone; select a thick hard rock layer at a certain distance above the water-conducting fracture zone, construct an auxiliary platform at the intersection of the selected thick hard rock layer and the open pit slope, and build a grouting station on the auxiliary platform;

[0008] b. constructing an auxiliary adit from the auxiliary platform along the selected thick hard rock formation toward the underground mine; constructing a tailwater tunnel and an electromechanical chamber connected to the tailwater tunnel from the open pit; when the auxiliary adit reaches the designed positions of the upper and lower headrace tunnels, constructing the upper and lower headrace tunnel approach holes as slag discharge holes, respectively; wherein the upper headrace tunnel is on the left and the lower headrace tunnel is on the right;

[0009] c. Excavate the upper and lower headrace tunnels simultaneously from top to bottom. The crushed rock generated from the excavation of the upper headrace tunnel will be discharged to the auxiliary adit, and the crushed rock generated from the excavation of the lower headrace tunnel will be discharged from the electromechanical chamber and tailrace tunnel to the open pit;

[0010] At the same time, auxiliary flat tunnels are continuously constructed in the direction of the underground mine. When the construction reaches the top of the collapse zone and the water-conducting fracture zone, grouting holes are constructed downward from the auxiliary flat tunnel to the collapse zone and the water-conducting fracture zone. Grouting slurry is prepared using a grouting station and injected into the collapse zone and the water-conducting fracture zone from the grouting holes. The auxiliary flat tunnel is continued to be excavated forward and grouting holes are constructed at set intervals to the collapse zone and the water-conducting fracture zone and grouting is carried out until the entire collapse zone and the water-conducting fracture zone are completely filled with grouting.

[0011] d. While carrying out steps ac, the reservoir is constructed on the basis of the collapse pit and the reservoir is constructed on the basis of the lower part of the open pit;

[0012] e. Seal the grouting boreholes and the auxiliary adit on the left side of the upper headrace tunnel with crushed stone or grouting. The auxiliary adit between the upper and lower headrace tunnels will serve as a transitional tunnel connecting the upper and lower headrace tunnels, with a surge chamber constructed in the transitional tunnel. Seal the connection between the right side of the lower headrace tunnel and the auxiliary adit.

[0013] At the same time, an upper trash rack is constructed at the connection between the upper diversion tunnel and the upper reservoir, and a lower trash rack is constructed at the connection between the lower diversion tunnel and the lower reservoir.

[0014] Preferably, in step b, a portion of the electromechanical chamber is constructed first to connect the lower diversion tunnel headhole with the tailwater tunnel as quickly as possible, and the remaining portion of the electromechanical chamber is constructed after the lower diversion tunnel is constructed.

[0015] Preferably, in step c, the grouting slurry is prepared by grinding the crushed stone generated during the construction of the upper water diversion tunnel and the auxiliary flat tunnel into crushed stone powder and mixing it with water; when the crushed stone generated during the construction of the upper water diversion tunnel and the auxiliary flat tunnel is insufficient, the crushed stone generated during the construction of the lower water diversion tunnel, the tailwater tunnel, the electromechanical chamber and the lower reservoir are ground into crushed stone powder and mixed with water.

[0016] Preferably, in step e, the auxiliary adit on the right side of the lower diversion tunnel is used as a maintenance chamber.

[0017] Preferably, in step e, when grouting sealing is adopted, the preparation method of the grouting slurry is as follows: the gravel generated during the construction of the lower water diversion tunnel, the tailwater tunnel, the electromechanical chamber and the lower reservoir is ground into gravel powder and mixed with water; when gravel sealing is adopted, the gravel comes from the gravel generated during the construction of the lower water diversion tunnel, the tailwater tunnel, the electromechanical chamber and the lower reservoir.

[0018] The beneficial effects of the present invention are as follows: the present invention uses the collapse pit formed by underground mining as the basis for constructing the upper reservoir, and uses the open pit mine as the basis for constructing the lower reservoir, which can reduce the construction volume of the upper and lower reservoirs. The present invention creatively proposes a construction plan for auxiliary flat tunnels, which can construct the water diversion tunnel while grouting the collapsed zone and the water-conducting fracture zone, and construct the upper and lower reservoirs at the same time. The parallel construction of multiple processes greatly saves the construction period and reduces the construction cost. In addition, the present invention uses the crushed stone produced by the construction of the water diversion tunnel, auxiliary flat tunnel, tailwater tunnel, electromechanical chamber and lower reservoir as grouting material or crushed stone sealing material, which reduces the process of lifting the crushed stone to the ground for processing, saves costs, and grouting the collapsed zone and the water-conducting fracture zone can ensure the stability of the upper reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a cross-sectional schematic diagram of the basic conditions of the open-pit mine pumped storage power station considering the influence of the goaf in the present invention;

[0020] Figure 2 This is a cross-sectional schematic diagram of the construction process of an open pit mine pumped storage power station taking into account the influence of goaf areas in the present invention;

[0021] Figure 3 This is a cross-sectional diagram of a completed open pit mine pumped storage power station taking into account the impact of goaf areas in the present invention;

[0022] In the figure, there is an underground coal seam 11; a collapsed zone 12; a water-conducting fracture zone 13; a subsidence pit 14; a ground surface 15; an open pit 16; an auxiliary platform 21; a grouting station 22; an auxiliary adit 23; a grouting borehole 24; an upper reservoir 31; an upper trash rack 32; an upper diversion tunnel 331; a lower diversion tunnel 332; a tailrace tunnel 333; a transition diversion tunnel 334; an electromechanical chamber 34; a lower trash rack 35; a lower reservoir 36; a surge chamber 37; and an inspection chamber 38. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0024] As Figure 1 shown, it is a basic profile schematic diagram of the open-pit mine pumped storage power station considering the influence of goaf, the left side is the abandoned mine of underground mining, the underground coal seam 11 has been mined out, part of the coal pillar is left, the overburden strata of the mined part of the underground coal seam 11 collapses and subsides, from bottom to top, forming a caving zone 12, a water flowing fractured zone 13 and a curved subsidence zone, a collapse pit 14 is formed on the uppermost part of the surface 15 of the curved subsidence zone; on the right side of the abandoned mine of underground mining is an open-pit mine 16, the coal mined by open-pit mining is relatively shallow, and the underground coal seam 11 is relatively deep. According to the terrain conditions and the existing research, the bottom of the open-pit mine 16 can be used as the construction basis of the lower reservoir, and the collapse pit 14 can be used as the construction basis of the upper reservoir, but there is residual compression space between the collapsed and broken rocks in the caving zone 12 and the water flowing fractured zone 13 at the lower part of the collapse pit 14, which will cause the collapse pit 14 to form long-term residual subsidence, but the collapse pit 14 needs to be stable as the upper reservoir, so the caving zone 12 and the water flowing fractured zone 13 need to be reinforced, the existing caving zone 12 and water flowing fractured zone 13 are often reinforced by grouting, but if the grouting reinforcement is constructed from the collapse pit 14, the construction of the upper reservoir will be affected, if the grouting reinforcement of the caving zone 12 and the water flowing fractured zone 13 and the construction of the diversion tunnel can be carried out at the same time without affecting the construction of the upper reservoir, it can certainly speed up the construction speed of the pumped storage power station, reduce the construction period and construction cost, for this, the present application proposes a construction method of open-pit mine pumped storage power station considering the influence of goaf, comprising the following steps:

[0025] a. As Figure 2 shown, the height of the water flowing fractured zone 13 after the underground coal seam 11 is mined is determined, and the positions of all thick and hard rock layers above the water flowing fractured zone 13 are determined; a certain thick and hard rock layer is selected at intervals on the water flowing fractured zone 13, an auxiliary platform 21 is constructed at the intersection of the selected thick and hard rock layer and the slope of the open-pit mine 16, and a grouting station 22 is constructed on the auxiliary platform 21;

[0026] b. An auxiliary flat tunnel 23 is constructed from the auxiliary platform 21 along the selected thick and hard rock layer to the direction of the underground mine; a tail water tunnel 333 and an electromechanical chamber 34 connected with the tail water tunnel 333 are constructed from the open-pit mine 16; when the auxiliary flat tunnel 23 is constructed to the design position of the upper diversion tunnel 331 and the lower diversion tunnel 332, the upper diversion tunnel lead hole and the lower diversion tunnel lead hole are respectively constructed as the residue discharge hole, the lead hole is a drill hole coaxial with the diversion tunnel and smaller in diameter than the diversion tunnel, the lead hole (or residue discharge hole) is a technology well known in the art, which will not be described here; the upper diversion tunnel 331 is on the left, and the lower diversion tunnel 332 is on the right;

[0027] c. Simultaneously excavating the upper and lower diversion tunnels 331 and 332 from top to bottom, wherein the gravel generated by excavating the upper diversion tunnel 331 is discharged to the auxiliary flat tunnel 23, and the gravel generated by excavating the lower diversion tunnel 332 is discharged from the electromechanical chamber 34 and the tailwater tunnel 333 to the open pit 16;

[0028] At the same time, the auxiliary adit 23 is continuously constructed in the direction of the underground mine. When the construction reaches the upper part of the collapsed zone 12 and the water-conducting fracture zone 13, a grouting borehole 24 is constructed downward from the auxiliary adit 23 to the collapsed zone 12 and the water-conducting fracture zone 13. Grouting slurry is prepared using the grouting station 22 and injected into the collapsed zone 12 and the water-conducting fracture zone 13 from the grouting borehole 24. The auxiliary adit 23 is further excavated forward and grouting boreholes 24 are constructed at set intervals to the collapsed zone 12 and the water-conducting fracture zone 13 and grouting is performed until the entire collapsed zone 12 and the water-conducting fracture zone 13 are completely filled with grouting. The grouting slurry is prepared by grinding the crushed stone generated during the construction of the upper water diversion tunnel 331 and the auxiliary adit 23 into crushed stone powder and mixing it with water to prepare the grouting slurry.

[0029] d. While carrying out steps ac, the upper reservoir 31 is constructed based on the collapse pit 14, and the lower reservoir 36 is constructed based on the open pit 16;

[0030] e. Figure 3 As shown, the grouting borehole 24 is sealed with crushed stone or grouting, and the auxiliary adit 23 on the left side of the upper diversion tunnel 331 is partially sealed with crushed stone or grouting; the auxiliary adit 23 between the upper diversion tunnel 331 and the lower diversion tunnel 332 serves as a transitional diversion tunnel 334 connecting the upper diversion tunnel 331 and the lower diversion tunnel 332, and a surge chamber 37 is constructed in the transitional diversion tunnel 334; the connection between the right side of the lower diversion tunnel 332 and the auxiliary adit 23 is sealed, and the auxiliary adit 23 on the right side of the lower diversion tunnel 332 will later be used as an inspection chamber 38;

[0031] At the same time, an upper trash rack 32 is constructed at the connection between the upper diversion tunnel 331 and the upper reservoir 31 , and a lower trash rack 35 is constructed at the connection between the lower diversion tunnel 332 and the tailrace tunnel 333 .

[0032] Among them, in step b, a part of the electromechanical chamber 34 can be constructed first to connect the lower water diversion tunnel opening with the tailwater tunnel 333 as soon as possible, and then the lower water diversion tunnel 332 can be constructed as soon as possible to facilitate slag discharge. After the lower water diversion tunnel 332 is constructed, the remaining part of the electromechanical chamber 34 can be continued to be constructed.

[0033] Among them, in step c, the preparation method of grouting slurry is: the gravel generated during the construction of the upper water diversion tunnel 331 and the auxiliary flat tunnel 23 is ground into gravel powder and mixed with water; when the gravel generated during the construction of the upper water diversion tunnel 331 and the auxiliary flat tunnel 23 is insufficient, the gravel generated during the construction of the lower water diversion tunnel 332, the tailwater tunnel 333, the electromechanical chamber 34 and the lower reservoir 36 are ground into gravel powder and mixed with water.

[0034] Preferably, in step e, the preparation method of the grouting slurry when grouting sealing is adopted is: the gravel generated during the construction of the lower water diversion tunnel 332, the tailwater tunnel 333, the electromechanical chamber 34 and the lower reservoir 36 is ground into gravel powder and mixed with water; when gravel sealing is adopted, the gravel comes from the gravel generated during the construction of the lower water diversion tunnel 332, the tailwater tunnel 333, the electromechanical chamber 34 and the lower reservoir 36.

[0035] 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. Construction method of open-pit mine pumped storage power station considering the influence of goaf. On the left is the abandoned mine with underground mining, and on the right is the abandoned open-pit mine. The coal mined in the open-pit is relatively shallow. It is characterized by: The steps include: a. Determine the height of the water-conducting fracture zone after underground coal seam mining and the location of all thick hard rock layers above the water-conducting fracture zone; select a thick hard rock layer above the water-conducting fracture zone, construct an auxiliary platform at the intersection of the selected thick hard rock layer and the open pit slope, and build a grouting station on the auxiliary platform; b. constructing an auxiliary adit from the auxiliary platform along the selected thick hard rock formation toward the underground mine; constructing a tailwater tunnel and an electromechanical chamber connected to the tailwater tunnel from the open pit; when the auxiliary adit reaches the designed positions of the upper and lower headrace tunnels, constructing the upper and lower headrace tunnel approach holes as slag discharge holes, respectively; wherein the upper headrace tunnel is on the left and the lower headrace tunnel is on the right; c. Excavate the upper and lower headrace tunnels simultaneously from top to bottom. The crushed rock generated from the excavation of the upper headrace tunnel will be discharged to the auxiliary adit, and the crushed rock generated from the excavation of the lower headrace tunnel will be discharged from the electromechanical chamber and tailrace tunnel to the open pit; At the same time, auxiliary flat tunnels are continuously constructed in the direction of the underground mine. When the construction reaches the top of the collapse zone and the water-conducting fracture zone, grouting holes are constructed downward from the auxiliary flat tunnel to the collapse zone and the water-conducting fracture zone. Grouting slurry is prepared using a grouting station and injected into the collapse zone and the water-conducting fracture zone from the grouting holes. The auxiliary flat tunnel is continued to be excavated forward and grouting holes are constructed at set intervals to the collapse zone and the water-conducting fracture zone and grouting is carried out until the entire collapse zone and the water-conducting fracture zone are completely filled with grouting. d. While carrying out steps ac, the reservoir is constructed on the basis of the collapse pit and the reservoir is constructed on the basis of the lower part of the open pit; e. Seal the grouting boreholes and the auxiliary adit on the left side of the upper headrace tunnel with crushed stone or grouting. The auxiliary adit between the upper and lower headrace tunnels will serve as a transitional tunnel connecting the upper and lower headrace tunnels, with a surge chamber constructed in the transitional tunnel. Seal the connection between the right side of the lower headrace tunnel and the auxiliary adit. At the same time, an upper trash rack is constructed at the connection between the upper diversion tunnel and the upper reservoir, and a lower trash rack is constructed at the connection between the lower diversion tunnel and the lower reservoir.

2. The construction method of an open pit mine pumped storage power station considering the influence of goaf according to claim 1 is characterized in that: In step b, a portion of the electromechanical chamber is first constructed to connect the lower headrace tunnel headhole with the tailrace tunnel as quickly as possible, and the remaining portion of the electromechanical chamber is continued to be constructed after the lower headrace tunnel is constructed.

3. The construction method of an open pit mine pumped storage power station considering the influence of goaf according to claim 1 is characterized in that: In step c, the grouting slurry is prepared by grinding the crushed stone generated during the construction of the upper water diversion tunnel and the auxiliary flat tunnel into crushed stone powder and mixing it with water; when the crushed stone generated during the construction of the upper water diversion tunnel and the auxiliary flat tunnel is insufficient, the crushed stone generated during the construction of the lower water diversion tunnel, the tailwater tunnel, the electromechanical chamber and the lower reservoir are ground into crushed stone powder and mixed with water.

4. The construction method of an open-pit mine pumped storage power station considering the influence of goaf according to claim 3 is characterized in that: In step e, the auxiliary adit on the right side of the lower diversion tunnel is used as an inspection chamber.

5. The construction method of an open-pit mine pumped storage power station considering the influence of goaf according to any one of claims 1 to 4, characterized in that: In step e, when grouting sealing is adopted, the preparation method of the grouting slurry is as follows: the gravel generated during the construction of the lower water diversion tunnel, the tailwater tunnel, the electromechanical chamber and the lower reservoir is ground into gravel powder and mixed with water; when gravel sealing is adopted, the gravel comes from the gravel generated during the construction of the lower water diversion tunnel, the tailwater tunnel, the electromechanical chamber and the lower reservoir.

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