Construction method for excavating water inlet and outlet of pumped storage power station

Abstract

This invention relates to a construction method for excavating the inlet and outlet of a pumped-storage power station, comprising the following steps: constructing a cofferdam structure on the inner side of the slope toe and pumping out the water within the cofferdam structure; constructing a tunnel structure on the portion of the slope toe located within the cofferdam structure; and excavating in opposite directions at the entrance of the tunnel structure and the outer side of the slope toe to complete the excavation of the inlet and outlet. The cofferdam structure can be constructed on the inner side of the slope toe to prepare for the tunnel structure construction. Subsequently, excavation can be carried out simultaneously at the entrance of the tunnel structure and the outer side of the slope toe to complete the excavation of the inlet and outlet. The construction of the cofferdam and tunnel structures does not require large-scale slope cutting, reducing the workload and saving costs. The original topography is maintained before and after construction, minimizing ecological disturbance and environmental damage. The construction process is mature, and the simultaneous excavation at both ends of the inlet and outlet results in a short construction period.

Description

Technical Field

[0001] This invention relates to the field of excavation for the inlet and outlet of pumped storage power stations, and particularly to a construction method for excavating the inlet and outlet of pumped storage power stations. Background Technology

[0002] The inlet and outlet structures of a pumped-storage power station reservoir are located near the main hydraulic structures, and their stability has a critical impact on the adjacent main hydraulic structures. The flow at the inlet and outlet of a pumped-storage power station must prevent the generation of suction vortices, and the outflow must require uniform diffusion of water flow in all channels, with uniform velocity and flow distribution. For example, the hydraulic problems of a side-type inlet and outlet in a pumped-storage power station are complex. Side-type inlets and outlets are a widely adopted flow transition structure in pumped-storage power stations, serving as the bottleneck connecting the reservoir area and the water transmission pipeline. The bidirectional flow transition structure at this location is relatively complex, significantly impacting the operational efficiency and safety of the project. A reasonable inlet and outlet shape is crucial to ensuring a proper flow transition and project safety.

[0003] Among the relevant technologies, the first construction method is pre-reserved rock retaining wall construction. Its advantages include no need for large-scale underwater filling and lower cost. Its disadvantages include a high slope formed by excavation, requiring significant excavation depth for strong unloading slope conditions, resulting in substantial excavation and support work. Furthermore, the slope is steep, with potentially unfavorable geological features, and large-scale excavation is detrimental to slope stability. The second construction method is rock plug construction. Its advantages include low cost, fast construction speed, and less seasonal impact on the construction period. Its disadvantages include a more complex construction process, requiring one-time rock plug blasting, high technical difficulty and risk for strong unloading slope conditions, and a high risk of over-excavation leading to blockage of the inlet and outlet. Summary of the Invention

[0004] This invention provides a construction method for excavating the inlet and outlet of a pumped storage power station, in order to solve the technical problems of complex operation, difficult construction, high cost, and long time consumption in the related art of excavating the inlet and outlet of pumped storage power stations.

[0005] This invention provides a construction method for excavating the inlet and outlet of a pumped storage power station, which includes the following steps:

[0006] Construct a cofferdam structure on the inner side of the slope toe where the water flows, and pump out the water from the cofferdam structure.

[0007] Construction of the tunnel structure will be carried out on the part of the slope toe located within the cofferdam structure.

[0008] Excavation was carried out in opposite directions at the entrance of the tunnel structure and on the outer side of the slope toe of the water inlet to complete the excavation of the inlet and outlet.

[0009] In some embodiments, the construction of a cofferdam structure on the inner side of the toe of the wading slope and the pumping out of the water within the cofferdam structure includes:

[0010] Construct a first single-layer cofferdam wall and a double-layer cofferdam wall on the inner side of the toe of the wading slope, and fill the double-layer cofferdam wall with crushed stone and slag; wherein, along the direction from the top to the bottom of the wading slope, the first single-layer cofferdam wall is located above the double-layer cofferdam wall.

[0011] Construct a second and a third single-layer cofferdam wall on the inner side of the slope toe of the water-prone area, so that a construction zone is formed between the first single-layer cofferdam wall, the double-layer cofferdam wall, the second single-layer cofferdam wall and the third single-layer cofferdam wall.

[0012] All water in the construction area was pumped out.

[0013] In some embodiments, the extraction of the construction area includes:

[0014] Layered pumping was carried out within the construction area;

[0015] Construct support components above the water level in the construction area, so that the support components are supported between the first single-layer cofferdam wall and the double-layer cofferdam wall.

[0016] Repeat the steps of stratified pumping and constructing support components within the construction area until all the water in the construction area is pumped out.

[0017] In some embodiments, the construction of a support assembly above the water level within the construction area, such that the support assembly is supported between the first single-layer cofferdam wall and the double-layer cofferdam wall, includes:

[0018] Brackets are installed on the inner side of both the first single-layer cofferdam wall and the inner side of the double-layer cofferdam wall.

[0019] Install an inner support rod between the two corbels.

[0020] In some embodiments, the construction of the tunnel structure at the toe of the wading slope within the cofferdam structure includes:

[0021] The curtain grouting area is constructed in the part of the slope toe located within the cofferdam structure, so that the depth of the curtain grouting area exceeds the strong unloading line of the slope toe.

[0022] Construction of the tunnel structure is carried out in the curtain grouting area.

[0023] In some embodiments, the construction of the grouting structure in the curtain grouting area includes:

[0024] Two underground continuous walls were constructed by excavating trenches in the curtain grouting area;

[0025] A structural platform was laid on top of the two concrete underground continuous walls to complete the construction of the shed structure.

[0026] In some embodiments, after the construction of the shed structure is completed by laying a structural platform on top of the two concrete diaphragm walls, the following steps are included:

[0027] Reinforced gabions and passive protective nets were constructed on the structural platform to serve as retaining walls.

[0028] In some embodiments, prior to the construction of the tunnel structure at the toe of the wading slope within the cofferdam structure, the following steps are included:

[0029] Construction of the pre-consolidation grouting area is carried out on the inner side of the toe of the water-touching slope, so that the depth of the pre-consolidation grouting area exceeds the strong unloading line of the toe of the water-touching slope; wherein, along the direction from the top to the bottom of the water-touching slope, the pre-consolidation grouting area is located above the cofferdam structure.

[0030] Backfill the top of the pre-consolidated grouting area with slag and install rockfall netting.

[0031] In some embodiments, the excavation work at the entrance of the tunnel structure and on the outer side of the wading slope to complete the excavation of the inlet and outlet includes:

[0032] At the entrance of the tunnel structure and on the outside of the slope toe, blasting was carried out simultaneously to excavate the working face;

[0033] The excavated tunnel is lined with reinforced concrete and supported by anchor bolts until the tunnel construction is completed.

[0034] In some embodiments, after excavating in opposite directions on the outside of the entrance to the tunnel structure and the toe of the wading slope to complete the excavation of the inlet and outlet, the process includes:

[0035] Backfill the top of the shed structure with slag and soil;

[0036] The cofferdam structure was dismantled.

[0037] The beneficial effects of the technical solution provided by this invention include: the cofferdam structure can be constructed on the inner side of the slope toe, preparing for the construction of the tunnel structure; subsequently, excavation can be carried out simultaneously at the entrance of the tunnel structure and the outer side of the slope toe to complete the excavation of the inlet and outlet; the construction of the cofferdam structure and the tunnel structure does not require large-scale slope cutting, reducing the amount of construction work and thus saving costs; the original topography and landform are maintained before and after construction, with less ecological disturbance and less environmental damage; the construction process is mature, and the inlet and outlet are excavated at the same time, resulting in a short construction period. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A schematic diagram illustrating the construction process of the inlet and outlet of a pumped storage power station according to an embodiment of the present invention;

[0040] Figure 2 This is a structural schematic diagram of the cofferdam construction provided in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the structure of the pre-consolidated grouting area, slag, and rock-blocking net after construction, provided in an embodiment of the present invention.

[0042] Figure 4 This is a schematic diagram of the structure of the shed after construction, provided in an embodiment of the present invention.

[0043] Figure 5 This is a structural schematic diagram of tunnel construction provided in an embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of the structure after the inlet and outlet construction is completed, as provided in an embodiment of the present invention.

[0045] In the diagram: 1. Water-crossing slope toe; 11. Strong unloading line; 12. Tunnel; 121. Anchor bolt; 2. Cofferdam structure; 21. Single-layer cofferdam wall; 22. Double-layer cofferdam wall; 23. Crushed stone material; 24. Support components; 241. Corbel; 242. Support rod; 25. Slag transport channel; 3. Shed structure; 31. Diaphragm wall; 32. Structural platform; 4. Curtain grouting area; 5. Reinforced gabion; 6. Passive protection net; 7. Pre-consolidated grouting area; 8. Slag and soil; 9. Rockfall barrier. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] This invention provides a construction method for excavating the inlet and outlet of a pumped storage power station, in order to solve the technical problems of complex operation, difficult construction, high cost, and long time consumption in the related art of excavating the inlet and outlet of pumped storage power stations.

[0048] like Figure 1 As shown in the figure, this embodiment of the invention provides a construction method for excavating the inlet and outlet of a pumped storage power station, which may include the following steps:

[0049] Step S100: Construct the cofferdam structure 2 on the inner side of the toe of the water-prone slope 1, and pump out the water inside the cofferdam structure 2;

[0050] Step S200: Construct the tunnel structure 3 in the part of the slope toe 1 located within the cofferdam structure 2;

[0051] Step S300: Excavate in opposite directions at the entrance of the tunnel structure 3 and the outside of the wading slope toe 1 to complete the excavation of the inlet and outlet.

[0052] Among them, such as Figure 2 As shown, the inner side of the toe of the wading slope 1 is the right side of the toe of the wading slope 1, and the outer side of the toe of the wading slope 1 is the left side of the toe of the wading slope 1. The cofferdam structure 2 can be constructed on the inner side of the toe of the wading slope 1 to prepare for the construction of the tunnel structure 3. Subsequently, excavation can be carried out simultaneously at the entrance of the tunnel structure 3 and the outer side of the toe of the wading slope 1 to complete the excavation of the inlet and outlet. The construction of the cofferdam structure 2 and the tunnel structure 3 does not require large-scale slope cutting, reducing the amount of construction work and thus saving costs. The original topography and landform are maintained before and after construction, with less ecological disturbance and less environmental damage. The construction procedures are mature, and the inlet and outlet are excavated at the same time, resulting in a short construction period.

[0053] In some embodiments, in step S100, such as Figure 2 As shown, the following steps may be included:

[0054] Step S110: Construct a first single-layer cofferdam wall 21 and a double-layer cofferdam wall 22 on the inner side of the toe of the water-crossing slope 1, and fill the double-layer cofferdam wall 22 with crushed stone material 23; wherein, along the direction from the top to the bottom of the slope 1, the first single-layer cofferdam wall 21 is located above the double-layer cofferdam wall 22.

[0055] Step S120: Construct a second and third single-layer cofferdam wall on the inner side of the toe of the wading slope 1, forming a construction area between the first single-layer cofferdam wall 21, the double-layer cofferdam wall 22, the second single-layer cofferdam wall, and the third single-layer cofferdam wall; wherein, the second and third single-layer cofferdam walls are attached to the... Figure 2 Not shown in the drawing, the second and third single-layer cofferdam walls should be in... Figure 2 The walls are distributed at intervals in the front and back directions and are connected and fixed between the first single-layer cofferdam wall 21 and the double-layer cofferdam wall 22 to form a construction area.

[0056] Step S130: Pump out all the water in the construction area.

[0057] In some embodiments, in step S130, such as Figure 2 , Figure 3 and Figure 4 As shown, the following steps may be included:

[0058] Step S131: Perform stratified pumping within the construction area;

[0059] Step S132: Construct support components 24 above the water level in the construction area, so that the support components 24 are supported between the first single-layer cofferdam wall 21 and the double-layer cofferdam wall 22;

[0060] Step S133: Repeat steps 24 of layered pumping and construction support assembly in the construction area until all water in the construction area is pumped out.

[0061] Among them, by repeatedly pumping water in layers and constructing support components 24 steps in the construction area, the stability and safety of the cofferdam structure 2 can be guaranteed. At the same time, its construction is convenient and reliable, which greatly ensures the safety of the workers in the construction area.

[0062] In some embodiments, in step S132, such as Figure 2 , Figure 3 and Figure 4 As shown, the following steps may be included:

[0063] Step S1321: Install brackets 241 on the inner side of both the first single-layer cofferdam wall 21 and the double-layer cofferdam wall 22;

[0064] Step S1322: Install the inner support rod 242 between the two brackets 241.

[0065] The installation of internal support rods 242 between the corbels 241 is convenient and quick, preventing collapse between the first single-layer cofferdam wall 21 and the double-layer cofferdam wall 22, thus providing good support. Alternatively, internal support rods 242 can also be installed between the corbels 241 on the second and third single-layer cofferdam walls to further ensure the safety and reliability of the cofferdam structure 2 itself.

[0066] In some embodiments, such as Figure 4 As shown, step S200 may include the following steps:

[0067] Step S230: Construct the curtain grouting area 4 in the part of the toe of the water-crossing slope 1 located within the cofferdam structure 2, so that the depth of the curtain grouting area 4 exceeds the strong unloading line 11 of the toe of the water-crossing slope 1.

[0068] Step S240: Construct the shed structure 3 in the curtain grouting area 4.

[0069] In some embodiments, in step S240, such as Figure 4 As shown, the following steps may be included:

[0070] Step S241: Excavate a trench in the curtain grouting area 4 to construct two underground diaphragm walls 31;

[0071] Step S242: Lay a structural platform 32 on top of the two concrete underground continuous walls 31 to complete the construction of the shed structure 3.

[0072] In some embodiments, after step S242, such as Figure 4 As shown, the following steps may be included:

[0073] Step S243: Construct reinforced gabion 5 and passive protective net 6 as a retaining wall on structural platform 32.

[0074] In some embodiments, before step S230, such as Figure 4 As shown, the following steps may be included:

[0075] Step S210: Construct the pre-consolidation grouting area 7 on the inner side of the toe of the water-eroded slope 1, so that the depth of the pre-consolidation grouting area 7 exceeds the strong unloading line 11 of the toe of the water-eroded slope 1; wherein, along the direction from the top to the bottom of the water-eroded slope 1, the pre-consolidation grouting area 7 is located above the cofferdam structure 2.

[0076] Step S220: Backfill the top of the pre-consolidated grouting area 7 with slag 8 and install the rockfall net 9.

[0077] In some embodiments, in step S300, such as Figure 5 As shown, the following steps may be included:

[0078] Step S310: Simultaneously excavate the working face by blasting at the entrance of the tunnel structure 3 and on the outside of the toe of the water-crossing slope 1;

[0079] Step S320: Lin the tunnel 12 with reinforced concrete and support it with anchor bolts 121 until the construction of tunnel 12 is completed.

[0080] In some embodiments, after step S300, such as Figure 6 As shown, the following steps may be included:

[0081] Step S400: Backfill the top of the shed structure 3 with slag soil 8;

[0082] Step S500: Remove the cofferdam structure 2.

[0083] In the embodiments mentioned above, the cofferdam structure 2 can be a steel sheet pile-I-beam composite structure. During construction preparation, it is necessary to inspect the steel sheet piles, lubricate the steel sheet pile interlocking joints and implement anti-seepage measures, measure and position, and install the guiding device. To improve the vertical bending resistance of the steel sheet pile cofferdam structure 2, the single-layer cofferdam wall 21 on the left side is constructed with intermittently driven steel sheet piles and I-beams, while the double-layer cofferdam wall 22 on the right side adopts a double-layer intermittently driven steel sheet pile-I-beam composite structure, with excavated crushed stone material 23 filling the middle.

[0084] In the embodiments mentioned above, after the cofferdam structure 2 is closed, foundation cleaning is required to ensure subsequent construction operations. After the cofferdam structure 2 is formed, curtain grouting is carried out to form a curtain grouting area 4, which intersects with the seepage line in the mountain and its depth exceeds the strong unloading line 11. The spacing between rows is 1.5m, and the arrangement is quincunx-shaped.

[0085] In the embodiments mentioned above, a pre-consolidation grouting area 7 is constructed in the area where the single-layer cofferdam wall 21 on the left side meets the slope line of the water-crossing slope toe 1 to reinforce the stability and waterproof performance of the strongly unloaded rock mass. There are a total of 3 rows of pre-consolidation grouting areas 7, with a row spacing of 4m×4m and a drilling depth exceeding the strongly unloaded line 11. At the same time, to prevent damage to the cofferdam structure 2 from falling rocks on the strongly unloaded slope surface, slag 8 is backfilled in this area and a rockfall net 9 is installed.

[0086] In the embodiments mentioned above, during the construction of the tunnel structure 3, reinforced concrete piers are poured upwards along the bottom of the ditch, and concrete is poured on both sides of the ditch to form underground continuous walls 31. Longitudinal and transverse I-beams are erected on the concrete piers at the bottom of the ditch and the underground continuous walls 31 on both sides as a framework, and reinforced concrete is laid on the surface to form a structural platform 32. Simultaneously, a reinforced gabion 5 and a passive protective net 6 are installed on the side closest to the river as a retaining wall. The entire structure serves as the tunnel structure 3 to prevent falling rocks from clogging the inlet and outlet.

[0087] In the embodiments mentioned above, the tunnel face is excavated simultaneously in the tunnel 12 and the cofferdam structure 2, and the excavation section is blasted. The excavated soil in the cofferdam structure 2 can be transported out through the slag transport channel 25. During the excavation process, reinforced concrete lining and anchor bolts 121 are used for support, and the lining thickness can be 1.5m.

[0088] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0089] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0090] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A construction method for excavating the inlet and outlet of a pumped storage power station, characterized in that, It includes the following steps: Construction of a cofferdam structure (2) is carried out on the inner side of the slope toe (1) and the water inside the cofferdam structure (2) is pumped out. Construction of the tunnel structure (3) is carried out on the part of the slope foot (1) located inside the cofferdam structure (2); Excavation is carried out in opposite directions at the entrance of the shed structure (3) and the outside of the water-crossing slope (1) to complete the excavation of the inlet and outlet. The construction of the cofferdam structure (2) on the inner side of the toe of the water-prone slope (1) and the pumping out of the water in the cofferdam structure (2) includes: Construct a first single-layer cofferdam wall (21) and a double-layer cofferdam wall (22) on the inner side of the toe of the water-crossing slope (1), and fill the double-layer cofferdam wall (22) with crushed stone material (23); wherein, along the direction from the top to the bottom of the slope of the toe of the water-crossing slope (1), the first single-layer cofferdam wall (21) is located above the double-layer cofferdam wall (22); Construct a second single-layer cofferdam wall and a third single-layer cofferdam wall on the inner side of the toe of the water-crossing slope (1), so that a construction area is formed between the first single-layer cofferdam wall (21), the double-layer cofferdam wall (22), the second single-layer cofferdam wall and the third single-layer cofferdam wall; All water in the construction area was pumped out. The construction of the tunnel structure (3) at the toe of the wading slope (1) within the cofferdam structure (2) includes: The curtain grouting area (4) is constructed in the part of the toe of the water-crossing slope (1) located inside the cofferdam structure (2), so that the depth of the curtain grouting area (4) exceeds the strong unloading line (11) of the toe of the water-crossing slope (1). Construction of the shed structure (3) is carried out in the curtain grouting area (4); In the curtain grouting area (4), two underground continuous walls (31) are constructed by excavating a trench. A structural platform (32) is laid on top of the two concrete underground continuous walls (31) to complete the construction of the shed structure (3); Before constructing the tunnel structure (3) in the portion of the slope toe (1) located within the cofferdam structure (2), the following is included: The pre-consolidation grouting area (7) is constructed on the inner side of the toe of the water-crossing slope (1), so that the depth of the pre-consolidation grouting area (7) exceeds the strong unloading line (11) of the toe of the water-crossing slope (1); wherein, along the direction from the top of the slope to the bottom of the slope of the toe of the water-crossing slope (1), the pre-consolidation grouting area (7) is located above the cofferdam structure (2). Backfill the top of the pre-consolidated grouting area (7) with slag (8) and install rockfall netting (9). The excavation work at the entrance of the tunnel structure (3) and the outer side of the wading slope (1) to complete the excavation of the inlet and outlet includes: At the entrance of the tunnel structure (3) and on the outside of the toe of the water-crossing slope (1), blasting excavation of the working face was carried out simultaneously; The excavated tunnel (12) is lined with reinforced concrete and supported by anchor bolts (121) until the tunnel (12) construction is completed.

2. The construction method for excavating the inlet and outlet of a pumped storage power station as described in claim 1, characterized in that: The process of pumping out all water from the construction area includes: Layered pumping was carried out within the construction area; Construct a support assembly (24) above the water level in the construction area, so that the support assembly (24) is supported between the first single-layer cofferdam wall (21) and the double-layer cofferdam wall (22); Repeat the steps of stratified pumping and construction support components (24) within the construction area until all water in the construction area is pumped out.

3. The construction method for excavating the inlet and outlet of a pumped storage power station as described in claim 2, characterized in that: The construction of the support assembly (24) above the water level in the construction area, such that the support assembly (24) is supported between the first single-layer cofferdam wall (21) and the double-layer cofferdam wall (22), includes: Brackets (241) are installed on the inner side of the first single-layer cofferdam wall (21) and the inner side of the double-layer cofferdam wall (22). An inner support rod (242) is installed between the two corbels (241).

4. The construction method for excavating the inlet and outlet of a pumped storage power station as described in claim 1, characterized in that: After the construction of the shed structure (3) is completed by laying a structural platform (32) on top of the two concrete underground continuous walls (31), the following are included: On the structural platform (32), reinforced gabions (5) and passive protective nets (6) are constructed as slag retaining walls.

5. The construction method for excavating the inlet and outlet of a pumped storage power station as described in claim 1, characterized in that: The excavation work at the entrance of the tunnel structure (3) and the outer side of the wading slope (1) is carried out in opposite directions. After the excavation work of the inlet and outlet is completed, the following is included: Backfill the top of the shed structure (3) with slag (8); (2) Remove the cofferdam structure.

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