Impermeable excavation construction method for percolation water intake project

Abstract

The invention discloses an anti-seepage excavation construction method for a percolation water taking project, and relates to the technical field of percolation water taking project construction.The anti-seepage excavation construction method for the percolation water taking project comprises the steps that a first construction area and a second construction area are formed through paying-off; a temporary water retaining cofferdam is constructed on the side, facing the river channel, of the first construction area; a steel sheet pile seepage interception wall is constructed around the first construction area; a high-pressure jet grouting pile diaphragm wall is constructed around the second construction area; after the steel sheet pile seepage prevention wall and the high-pressure jet grouting pile seepage prevention wall are formed, the high-pressure jet grouting pile seepage prevention wall at the communicating position of the first construction area and the second construction area is broken, and the high-pressure jet grouting pile seepage prevention wall and the steel sheet pile seepage prevention wall communicate with each other; in the extending direction of the steel sheet pile seepage-stopping wall, a flood-fighting cofferdam is constructed on the side, facing the first construction area, of the steel sheet pile seepage-stopping wall; and excavating to form a water collecting gallery and a booster pump station. The steel sheet pile seepage interception wall is constructed preferentially, so that the steel sheet pile seepage interception wall plays a role in protecting follow-up construction, and the construction quality is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of infiltration water intake project construction, and in particular to an anti-seepage excavation construction method for infiltration water intake project. Background Art

[0002] Infiltration water extraction project is a technology that uses the self-purification function of the natural environment to obtain clean drinking water from rivers with different degrees of pollution. Infiltration water extraction projects usually include water collection corridors and pressure pumping stations. The working principle of infiltration water extraction projects is to use natural riverbeds or artificial filter layers to infiltrate river water. Pollutants and impurities in the river water are adsorbed and filtered by the filter membrane and sand and gravel layer on the surface of the riverbed. The filtered water source is collected through the water collection corridor, and then the water source that meets the standards is pressurized and extracted through the pressure pumping station.

[0003] Since the water collection corridor and booster pump station are usually located on one side of the river channel and buried beneath the ground, the construction site is mostly composed of large-size gravel strata with extremely strong permeability. During the excavation and construction of the infiltration water extraction project, the surface water in the river channel and the groundwater in the riverbed can easily infiltrate into the construction area, resulting in an unstable construction environment and affecting the construction quality. Summary of the invention

[0004] The main purpose of the present invention is to propose an anti-seepage excavation construction method for infiltration water intake projects, aiming to solve the problem that during the excavation construction of infiltration water intake projects in the prior art, surface water in the river channel and groundwater in the riverbed easily infiltrate into the construction area, resulting in an unstable construction environment, thereby affecting the construction quality.

[0005] To achieve the above-mentioned purpose, the present invention proposes an anti-seepage excavation construction method for an infiltration water intake project, wherein the infiltration water intake project includes a water collection gallery and a pressure pump station, wherein the water collection gallery is located on one side of a river channel, and the anti-seepage excavation construction method for an infiltration water intake project includes the following steps: laying out a first construction area and a second construction area according to the positions of the water collection gallery and the pressure pump station; constructing a temporary water retaining cofferdam on one side of the first construction area facing the river channel; constructing a steel sheet pile seepage cutoff wall around the first construction area; and constructing a steel sheet pile seepage cutoff wall in the second construction area. A high-pressure rotary jet pile anti-seepage wall is constructed around the area; after the steel sheet pile seepage cut-off wall and the high-pressure rotary jet pile anti-seepage wall are formed, the high-pressure rotary jet pile anti-seepage wall at the connection between the first construction area and the second construction area is broken down to make the high-pressure rotary jet pile anti-seepage wall and the steel sheet pile seepage cut-off wall connected to each other; along the extension direction of the steel sheet pile seepage cut-off wall, a flood control cofferdam is constructed on the side of the steel sheet pile seepage cut-off wall facing the first construction area; the first construction area is excavated to form the water collection corridor; the second construction area is excavated to form the booster pump station.

[0006] In one embodiment, the step of constructing a steel sheet pile seepage cutoff wall around the first construction area includes: excavating a pit in a backward manner; draining the pit; backfilling the pit with gravel; and inserting steel sheet piles into the backfilled pit to form the steel sheet pile seepage cutoff wall.

[0007] In one embodiment, the step of backfilling the pit with gravel includes: backfilling the portion of the pit below the bedrock with medium-coarse sand; and backfilling the portion of the pit above the bedrock with small-size excavated gravel.

[0008] In one embodiment, the step of draining the pit includes: providing a buoy platform in the pit; and providing a centrifugal pump and a submersible pump on the buoy platform to drain the pit.

[0009] In one embodiment, after the step of backfilling the pit with sand and gravel, the method further comprises: installing a steel sheet pile positioning frame in the pit.

[0010] In one embodiment, the step of constructing a flood control cofferdam on the side of the steel sheet pile cutoff wall facing the first construction area along the extension direction of the steel sheet pile cutoff wall includes: filling soil along the top of the steel sheet pile cutoff wall and on the side of the steel sheet pile cutoff wall facing the first construction area; rolling the soil and trimming the slopes on both sides of the soil to the designed slope; laying a geomembrane on the slope of the soil facing the river channel and connecting it to the steel sheet pile cutoff wall; and building an eco-bag on the geomembrane.

[0011] In one embodiment, the step of constructing a high-pressure rotary jet grouting anti-seepage wall around the second construction area includes: drilling a hole at the edge of the second construction area using a follow-up pipe drilling method to ensure that the bottom of the hole is not less than 1 m below the soil-rock boundary line; sequentially delivering high-pressure water, cement slurry and compressed air into the hole through a jet pipe; statically spraying at the bottom of the hole for 1 to 3 minutes until slurry emerges from the hole mouth; performing a jetting operation from bottom to top at a preset lifting, rotating or swinging speed to form a single high-pressure rotary jet grouting pile; repeating the above steps until a plurality of the high-pressure rotary jet grouting piles are interconnected to form the high-pressure rotary jet grouting anti-seepage wall.

[0012] In one embodiment, the step of excavating the second construction area to form the booster pump station includes: vertically dividing the second construction area into multiple layers of geological bodies according to the design depth of the booster pump station; constructing a transportation road that runs through the second construction area in the middle of the second construction area; excavating the first layer of geological bodies in the second construction area except the transportation road; keeping the height of the end point of the transportation road fixed, excavating the transportation road until the starting point of the transportation road is flush with the bottom of the first layer of geological bodies; repeating the step of excavating the first layer of geological bodies except the transportation road until the depth of the starting point of the transportation road reaches the design depth of the booster pump station; and excavating the geological bodies in the transportation road backwards from the starting point to the end point of the transportation road to form the booster pump station.

[0013] In one embodiment, the step of excavating the first layer of geological body in the second construction area except the transport road includes: excavating the first layer of geological body backwards from the boundary line of the second construction area toward the transport road; excavating a collection well at the starting point of the transport road; excavating drainage ditches on both sides of the transport road; and constructing safety guardrails on both sides of the transport road.

[0014] In one embodiment, after the step of constructing a flood control cofferdam along the extension direction of the steel sheet pile cut-off wall and on the side of the steel sheet pile cut-off wall facing the first construction area, the method further comprises the step of: dismantling the temporary water retaining cofferdam.

[0015] The anti-seepage excavation construction method for the infiltration water extraction project proposed by the present invention separates the river channel from the first construction area and the second construction area by constructing a temporary water retaining cofferdam on one side of the river channel to keep the first construction area and the second construction area dry, so as to facilitate the construction of a steel sheet pile seepage cut-off wall in the first construction area and the construction of a high-pressure rotary jet pile anti-seepage wall in the second construction area. By preferentially constructing the steel sheet pile seepage cut-off wall and then constructing the high-pressure rotary jet pile anti-seepage wall after the steel sheet pile seepage cut-off wall is formed, the formed steel sheet pile seepage cut-off wall plays a protective role during the construction process of the high-pressure rotary jet pile anti-seepage wall, and can effectively block the groundwater on one side of the river channel from infiltrating into the second construction area, preventing the groundwater from affecting the construction of the high-pressure rotary jet pile anti-seepage wall, and ensuring the construction quality of the high-pressure rotary jet pile anti-seepage wall. After the high-pressure rotary jet pile anti-seepage wall is formed, the high-pressure rotary jet pile seepage cut-off wall at the connection between the first construction area and the second construction area is broken, so that the steel sheet pile seepage cut-off wall and the high-pressure rotary jet pile anti-seepage wall are interconnected to form an integrated anti-seepage structure, which greatly enhances the anti-seepage effect and structural stability of the entire construction area, effectively prevents external groundwater from infiltrating into the construction area, and maintains a stable and dry construction environment for the first construction area and the second construction area. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0017] Figure 1 A schematic construction plan view of an embodiment of an anti-seepage excavation construction method for a percolation water intake project provided by the present invention;

[0018] Figure 2 A schematic elevational view of an embodiment of a temporary water retaining cofferdam, a flood-proof cofferdam and a steel sheet pile seepage cut-off wall in the anti-seepage excavation construction method for a seepage water intake project provided by the present invention;

[0019] Figure 3 A schematic plan view of an embodiment of a second construction area in the anti-seepage excavation construction method for a percolation water intake project provided by the present invention before excavation;

[0020] Figure 4 A schematic plan view of an embodiment of a second construction area after excavation in the anti-seepage excavation construction method for an infiltration water intake project provided by the present invention;

[0021] Figure 5 The present invention provides a schematic flow chart of an embodiment of the anti-seepage excavation construction method for an infiltration water intake project.

[0022] Description of Figure Numbers:

[0023] 10. First construction area; 20. Second construction area; 30. Steel sheet pile cut-off wall; 40. High-pressure jet jet pile anti-seepage wall; 50. Temporary water retaining cofferdam; 60. Flood control cofferdam; 70. Construction road.

[0024] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0027] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0028] In the prior art, since the water collection corridor and the booster pump station are usually located on one side of the river channel and buried below the ground, during the excavation and construction of the infiltration water extraction project, surface water in the river channel and groundwater in the riverbed can easily seep into the construction area, resulting in an unstable construction environment and thus affecting the construction quality.

[0029] The present invention provides a seepage-proof excavation construction method for a seepage-intake water project. The seepage-intake water project includes a water collection gallery and a pressure pump station. The water collection gallery is located on one side of a river channel. The seepage-proof excavation construction method for a seepage-intake water project provided by the present invention includes the following steps:

[0030] S10: laying out a first construction area and a second construction area according to the positions of the water collection corridor and the booster pump station;

[0031] S20: constructing a temporary water retaining cofferdam on the side of the first construction area facing the river channel;

[0032] S30: constructing a steel sheet pile cut-off wall around the first construction area;

[0033] S40: constructing a high-pressure jet grouting pile anti-seepage wall around the second construction area;

[0034] S50: After the steel sheet pile seepage cut-off wall and the high-pressure rotary jet pile anti-seepage wall are formed, the high-pressure rotary jet pile anti-seepage wall at the connection between the first construction area and the second construction area is broken down to make the high-pressure rotary jet pile anti-seepage wall and the steel sheet pile seepage cut-off wall connected to each other;

[0035] S60: constructing a flood control cofferdam on a side of the steel sheet pile cut-off wall facing the first construction area along the extension direction of the steel sheet pile cut-off wall;

[0036] S70: excavating the first construction area to form the water collection corridor;

[0037] S80: Excavating the second construction area to form the booster pump station.

[0038] See also Figure 1 and Figure 5 The first construction area 10 is located beside the river channel, and the second construction area 20 is located on the side of the first construction area 10 away from the river channel. The river channel and the first construction area 10 are separated by constructing a temporary water retaining cofferdam 50 to prevent the surface water in the river channel from entering the first construction area 10 and the second construction area 20, so that the first construction area 10 and the second construction area 20 remain dry, which is convenient for the subsequent construction of the steel sheet pile seepage cut-off wall 30 and the high-pressure rotary jet pile anti-seepage wall 40. The steel sheet pile seepage cut-off wall 30 is constructed first, and the high-pressure rotary jet pile anti-seepage wall 40 is constructed after the steel sheet pile seepage cut-off wall 30 is formed, so that the formed steel sheet pile seepage cut-off wall 30 plays a protective role during the construction process of the high-pressure rotary jet pile anti-seepage wall 40, and can effectively block the groundwater on one side of the river channel from infiltrating into the second construction area 20, and prevent the groundwater from affecting the construction of the high-pressure rotary jet pile anti-seepage wall 40. The steel sheet pile cut-off wall 30 is arranged around the first construction area 10, and the high-pressure rotary jet pile anti-seepage wall 40 is arranged around the second construction area 20. The first construction area 10 and the second construction area 20 are interconnected. After the high-pressure rotary jet pile anti-seepage wall 40 is formed, the high-pressure rotary jet pile anti-seepage wall 40 at the connection between the first construction area 10 and the second construction area 20 is broken, so that the steel sheet pile cut-off wall 30 and the high-pressure rotary jet pile anti-seepage wall 40 are interconnected and form an integrated anti-seepage structure together, effectively enhancing the anti-seepage effect and structural stability of the entire construction area, and preventing external groundwater from infiltrating into the construction area. The flood-proof cofferdam 60 is arranged on the side of the steel sheet pile cut-off wall 30 facing the first construction area 10. The extension direction of the flood-proof cofferdam 60 is consistent with the extension direction of the steel sheet pile cut-off wall 30, and the edge of the flood-proof cofferdam 60 is flush with the top of the steel sheet pile cut-off wall 30, so that the flood-proof cofferdam 60 and the steel sheet pile cut-off wall 30 form an integrated structure, and respectively block surface water and groundwater, effectively maintaining a dry construction environment in the first construction area 10 and the second construction area 20.

[0039] The anti-seepage excavation construction method for the infiltration water extraction project proposed by the present invention separates the river channel from the first construction area 10 and the second construction area 20 by constructing a temporary water retaining cofferdam 50 on one side of the river channel, so as to keep the first construction area 10 and the second construction area 20 dry, so as to facilitate the construction of the steel sheet pile seepage cut-off wall 30 in the first construction area 10 and the construction of the high-pressure rotary jet pile anti-seepage wall 40 in the second construction area 20. By constructing the steel sheet pile seepage cut-off wall 30 first, and then constructing the high-pressure rotary jet pile anti-seepage wall 40 after the steel sheet pile seepage cut-off wall 30 is formed, the formed steel sheet pile seepage cut-off wall 30 plays a protective role during the construction process of the high-pressure rotary jet pile anti-seepage wall 40, and can effectively block the groundwater on one side of the river channel from infiltrating into the second construction area 20, prevent the groundwater from affecting the construction of the high-pressure rotary jet pile anti-seepage wall 40, and ensure the construction quality of the high-pressure rotary jet pile anti-seepage wall 40. After the high-pressure rotary jet pile anti-seepage wall 40 is formed, the high-pressure rotary jet pile anti-seepage wall 40 at the connection between the first construction area 10 and the second construction area 20 is broken, so that the steel sheet pile cut-off wall 30 and the high-pressure rotary jet pile anti-seepage wall 40 are interconnected to form an integrated anti-seepage structure, which greatly enhances the anti-seepage effect and structural stability of the entire construction area, effectively prevents external groundwater from infiltrating into the construction area, and maintains a stable and dry construction environment for the first construction area 10 and the second construction area 20.

[0040] In one embodiment, step S30 includes:

[0041] S31: Backward excavation of trench;

[0042] S32: performing drainage treatment on the pit;

[0043] S33: backfilling the pit with gravel;

[0044] S34: Inserting steel sheet piles into the pit after backfilling to form the steel sheet pile seepage cutoff wall.

[0045] It should be noted that the retreat-type excavation of the pit ensures the continuity and safety of the construction, while reducing the impact on the surrounding environment. The drainage treatment and gravel backfilling steps provide a solid foundation for the insertion of steel sheet piles and effectively prevent the infiltration of groundwater. By inserting steel sheet piles in the backfilled pit, a solid steel sheet pile cut-off wall 30 is formed, which not only enhances the anti-seepage effect of the construction area, but also improves the stability of the structure.

[0046] In one embodiment, step S33 includes:

[0047] S331: backfilling the portion of the pit below the bedrock with medium-coarse sand;

[0048] S331: Use small-size excavated gravel to backfill the portion of the pit above the bedrock.

[0049] After the foundation pit is drained, composite stones are used for backfilling. The composite stones include medium-coarse sand and fine pebbles. The part below the bedrock layer is backfilled with medium-coarse sand, and the part above the bedrock layer is backfilled with fine pebbles to ensure the stability of the foundation pit and provide good support for the steel sheet pile cut-off wall 30.

[0050] In one embodiment, step S32 includes:

[0051] S321: Arrange a buoy platform in the pit;

[0052] S322: A centrifugal pump and a submersible pump are arranged on the pontoon platform to drain the pit.

[0053] It can be explained that before the construction of the steel sheet pile cut-off wall 30, the seepage water in the foundation pit needs to be drained. A floating platform is set in the foundation pit, and a centrifugal pump combined with a submersible pump is set on the floating platform to pump water. The seepage water in the foundation pit is discharged to the sedimentation tank outside the cofferdam through a water pipe, and then discharged into the river after sedimentation. When draining the foundation pit, the precipitation rate is strictly controlled, and the deformation of the slope of the foundation pit is monitored to prevent the slope from becoming unstable due to drainage.

[0054] In one embodiment, after step S33, the anti-seepage excavation construction method for the infiltration water intake project further comprises the following steps:

[0055] S329: Install a steel sheet pile positioning frame in the pit.

[0056] A steel sheet pile positioning frame is installed in the foundation pit after backfilling to facilitate the steel sheet piles to be driven into the geological body at a preset angle and position, effectively preventing the steel sheet piles from deforming.

[0057] In one embodiment, step S60 includes:

[0058] S61: filling soil along the top of the steel sheet pile cut-off wall on one side of the steel sheet pile cut-off wall toward the first construction area;

[0059] S62: rolling the soil and trimming the slopes on both sides of the soil to a designed slope;

[0060] S63: laying a geomembrane on the slope of the soil body facing the river channel and connecting it to the steel sheet pile cut-off wall;

[0061] S64: Building ecological bags on the geomembrane.

[0062] It can be understood that the flood-proof cofferdam 60 is arranged on the side of the steel sheet pile seepage cutoff wall 30 facing the first construction area 10, and the outer edge of the flood-proof cofferdam 60 is flush with the top of the steel sheet pile seepage cutoff wall 30, the direction in which the soil extends from the top of the steel sheet pile seepage cutoff wall 30 to the first construction area 10 is the width direction of the flood-proof cofferdam 60, and the soil extends along the extension direction of the steel sheet pile seepage cutoff wall 30, and the extension direction of the steel sheet pile seepage cutoff wall 30 is the length direction of the flood-proof cofferdam 60. When constructing the flood-proof cofferdam 60, the soil that meets the anti-seepage requirements is filled and compacted to improve the density of the soil; the soil is rolled by using a roller in a static pressure, weak vibration, multiple strong vibrations and static pressure, and the gaps between soil particles are eliminated by dynamic rolling, and finally the unevenness caused by dynamic rolling is eliminated by static pressure. By rolling the soil in a dynamic and static rolling method, the density of the soil can be gradually improved and the uniformity of the soil can be maintained, so as to ensure that the soil structure remains stable during the rolling process, and finally the soil reaches the preset density while maintaining good uniformity, thereby enhancing the bearing capacity and anti-seepage effect of the soil. Then the slopes on both sides of the soil along the width direction are trimmed to the designed slope to ensure that the slopes of the flood cofferdam 60 remain stable and can block the scouring and erosion of ground water; finally, geomembranes are laid and ecological bags are built on the side of the flood cofferdam 60 facing the river channel to ensure that the water-facing surface of the flood cofferdam 60 can prevent the infiltration of ground water, effectively improving the anti-seepage effect of the flood cofferdam 60, thereby ensuring a dry environment in the first construction area 10 and the second construction area 20. The ecological bags are pressed on the top of the flood control cofferdam 60 to ensure the stability of the flood control cofferdam 60 while providing a growth environment for plants, which is conducive to the ecological restoration of the river. After the construction is completed, the flood control cofferdam 60 can be used as a buffer structure during the flood season of the river and provide long-term protection for the infiltration water intake project.

[0063] In one embodiment, step S40 includes:

[0064] S41: Drilling a hole at the edge of the second construction area by using a pipe drilling method to ensure that the bottom of the hole is not less than 1m below the soil-rock boundary line;

[0065] S42: sending high-pressure water, cement slurry and compressed air into the hole in sequence through the injection pipe;

[0066] S43: statically spray at the bottom of the hole for 1 to 3 minutes until slurry emerges from the hole mouth;

[0067] S44: performing a jetting operation from bottom to top at a preset lifting, rotating or swinging speed to form a single high-pressure jetting pile;

[0068] S45: Repeat the above steps until a plurality of the high-pressure jet grouting piles are interconnected to form the high-pressure jet grouting pile anti-seepage wall.

[0069] It should be noted that the booster pump station uses a high-pressure rotary jet pile anti-seepage wall 40 for anti-seepage and support treatment, and the high-pressure rotary jet pile anti-seepage wall 40 is arranged around the edge of the second construction area 20. During the construction of a single high-pressure rotary jet pile, the injection pipe is extended into the hole after drilling, and high-pressure water, cement slurry and compressed air are sent through the injection pipe. The cement slurry is fully mixed in the hole through high-pressure water and compressed air and infiltrated into the geological body around the hole wall, so that the high-pressure rotary jet pile is tightly combined with the geological body. Spray statically at the bottom of the hole for 1 to 3 minutes until slurry emerges from the hole mouth to ensure that the cement slurry fully reacts at the bottom of the hole to form a stable solidification and bonding layer. Then, according to the preset lifting, rotation or swinging speed, the injection operation is carried out from bottom to top until a single high-pressure rotary jet pile is formed. Repeat the above steps until multiple high-pressure rotary jet piles are interconnected to form a continuous anti-seepage wall to ensure the anti-seepage effect. Finally, by breaking down the high-pressure rotary jet pile anti-seepage wall 40 at the connection between the first construction area 10 and the second construction area 20, the high-pressure rotary jet pile anti-seepage wall 40 and the steel sheet pile seepage cut-off wall 30 are connected to each other, and the first construction area 10 and the second construction area 20 are connected underground as a whole. The high-pressure rotary jet pile anti-seepage wall 40 and the steel sheet pile seepage cut-off wall 30 jointly prevent external groundwater from infiltrating into the construction area, effectively improving the anti-seepage performance and structural stability of the first construction area 10 and the second construction area 20, and ensuring the stable and safe construction of the infiltration water extraction project.

[0070] In one embodiment, step S80 includes:

[0071] S81: vertically dividing the second construction area into multiple layers of geological bodies according to the design depth of the booster pump station;

[0072] S82: constructing a transportation road that runs through the second construction area in the middle of the second construction area;

[0073] S83: excavating the first layer of geological body in the second construction area except the transportation road;

[0074] S84: keeping the height of the end point of the transport road fixed, and excavating the transport road until the starting point of the transport road is flush with the bottom of the first geological layer;

[0075] S85: Repeat the step of excavating the first layer of geological bodies except the transportation road until the starting depth of the transportation road reaches the design depth of the booster pump station;

[0076] S86: Excavate the geological body within the transport road backwards from the starting point to the end point of the transport road to form the booster pump station.

[0077] See also Figure 3 and Figure 4, by vertically dividing the second construction area 20 into multiple layers of geological bodies, the depth of each layer is limited to within 6m, and the excavation depth is precisely controlled to ensure the stability and anti-seepage effect of the slope structure of the second construction area 20 during the excavation process. The excavation of the second construction area 20 is excavated from each side to the middle, and the transportation road is built in the middle of the second construction area 20, which is convenient for transporting the geological bodies around the transportation road to the transportation road, thereby improving the transportation efficiency. The transportation road is connected between the middle of the second construction area 20 and the external abandoned soil area. The transportation starting point of the transportation road is the middle of the second construction area 20. As the excavation depth of the second construction area 20 gradually deepens, the starting point depth of the transportation road also gradually deepens. After the excavation of each layer of geological body is completed, the geological body at the starting point of the transportation road needs to be excavated, and the height of the starting point of the transportation road is kept consistent with the height of the middle of the second construction area 20, and the slope of the transportation road is correspondingly trimmed, so that the transportation road is connected between the middle of the second construction area 20 and the external abandoned soil area, which is convenient for abandoning soil and greatly improves the transportation efficiency. After the excavation of the geological body except the transportation road range is completed, the geological body within the transportation road range is finally excavated from the starting point to the end point of the transportation road to ensure that all the geological bodies in the second construction area 20 are excavated and the soil abandonment is smooth.

[0078] Since the water collection corridor is in the shape of a long strip, the water collection corridor is formed by excavating the first construction area 10 in sections, and excavation is carried out from the end of the first construction area 10 away from the second construction area 20 toward the second construction area 20, so that the soil excavated in the first construction area 10 and the soil excavated in the second construction area 20 can be transported and abandoned together. Since the buried depth of the booster pump station is deeper than that of the water collection corridor, the booster pump station is formed by excavating the second construction area 20 in layers to ensure that the second construction area 20 remains stable during the excavation process. The first construction area 10 and the second construction area 20 can be excavated and abandoned together at the same time, which effectively improves the construction efficiency.

[0079] In one embodiment, step S83 includes:

[0080] S831: excavating the first layer of geological body backwards from the boundary line of the second construction area toward the transportation road;

[0081] S832: Digging a water collection well at the starting point of the transportation road;

[0082] S833: Digging drainage ditches on both sides of the transport road;

[0083] S834: Construct safety guardrails on both sides of the transport road.

[0084] It can be explained that, since the excavation depth of the second construction area 20 is relatively large, after the excavation of each layer of geological body, drainage ditches and water collection wells are promptly constructed to ensure that the seepage within the scope of each layer of geological body does not affect the excavation of the next layer, and to ensure that the next layer of geological body remains stable during the excavation process. At the same time, safety guardrails are promptly constructed to ensure the safety of construction workers.

[0085] In one embodiment, after step S60, the anti-seepage excavation construction method for the infiltration water intake project proposed by the present invention further includes the following steps:

[0086] S65: Dismantle the temporary water retaining cofferdam.

[0087] See also Figure 2 The temporary water retaining cofferdam 50 is used to keep the construction environment dry during the construction of the steel sheet pile cut-off wall 30 and the high-pressure rotary jet pile anti-seepage wall 40. After the flood control cofferdam 60 and the steel sheet pile cut-off wall 30 are completed, the flood control cofferdam 60 and the steel sheet pile are vertically connected to each other, and the flood control cofferdam 60 and the steel sheet pile cut-off wall 30 can respectively block and prevent the surface water and groundwater on one side of the river channel. The temporary water retaining cofferdam 50 can be dismantled to reduce the disturbance of the river channel caused by the construction, and the geological body generated by the dismantling of the temporary water retaining cofferdam 50 can be discarded together with the geological body generated by the excavation of the first construction area 10 and the second construction area 20, thereby improving the construction efficiency.

[0088] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for anti-seepage excavation construction of a percolation water intake project, characterized in that: The infiltration water intake project includes a water collection gallery and a pressure pump station. The water collection gallery is located on one side of the river. The anti-seepage excavation construction method of the infiltration water intake project includes the following steps: According to the positions of the water collection corridor and the booster pump station, a first construction area and a second construction area are respectively laid out; Constructing a temporary water retaining cofferdam on the side of the first construction area facing the river channel; Constructing a steel sheet pile cut-off wall around the first construction area; Constructing a high-pressure jet-jet pile anti-seepage wall around the second construction area; After the steel sheet pile seepage cut-off wall and the high-pressure rotary jet pile anti-seepage wall are formed, the high-pressure rotary jet pile anti-seepage wall at the connection between the first construction area and the second construction area is broken down to make the high-pressure rotary jet pile anti-seepage wall and the steel sheet pile seepage cut-off wall connected to each other; Constructing a flood control cofferdam on the side of the steel sheet pile cut-off wall facing the first construction area along the extension direction of the steel sheet pile cut-off wall; Excavating the first construction area to form the water collection corridor; The second construction area is excavated to form the booster pump station.

2. The anti-seepage excavation construction method for infiltration water intake engineering according to claim 1, characterized in that: The step of constructing a steel sheet pile cut-off wall around the first construction area comprises: Backward excavation of trenches; Performing drainage treatment on the pit; backfilling the pit with gravel; Steel sheet piles are inserted into the pit after backfilling to form the steel sheet pile seepage cutoff wall.

3. The anti-seepage excavation construction method for infiltration water intake engineering according to claim 2, characterized in that: The step of backfilling the pit with gravel material comprises: Backfilling the portion of the pit below the bedrock with medium-coarse sand; The portion of the pit located above the bedrock is backfilled with small-size excavated gravel.

4. The anti-seepage excavation construction method for infiltration water intake engineering according to claim 2, characterized in that: The step of draining the pit comprises: Arranging a buoy platform in the pit; A centrifugal pump and a submersible pump are arranged on the buoy platform to drain the pit.

5. The anti-seepage excavation construction method for infiltration water intake engineering according to claim 2, characterized in that: After the step of backfilling the pit with sand and gravel, the method further comprises: A steel sheet pile positioning frame is installed in the pit.

6. The anti-seepage excavation construction method for a percolation water intake project according to any one of claims 1 to 5, characterized in that: The step of constructing a flood control cofferdam on a side of the steel sheet pile cut-off wall facing the first construction area along the extension direction of the steel sheet pile cut-off wall comprises: Filling soil along the top of the steel sheet pile cut-off wall and on the side of the steel sheet pile cut-off wall facing the first construction area; Rolling the soil and trimming the slopes on both sides of the soil to the designed slope; Laying a geomembrane on the slope of the soil body facing the river channel and connecting it to the steel sheet pile cut-off wall; Eco-bags are built on the geomembrane.

7. The anti-seepage excavation construction method for a percolation water intake project according to any one of claims 1 to 5, characterized in that: The step of constructing a high-pressure jet grouting pile anti-seepage wall around the second construction area comprises: Drill holes at the edge of the second construction area using a pipe drilling method to ensure that the bottom of the hole is no less than 1m below the soil-rock boundary line; High-pressure water, cement slurry and compressed air are sequentially fed into the hole through the jet pipe; Spray statically at the bottom of the hole for 1 to 3 minutes until slurry emerges from the hole; According to the preset lifting, rotating or swinging speed, the spraying operation is carried out from bottom to top to form a single high-pressure jetting pile; Repeat the above steps until a plurality of the high-pressure jet grouting piles are interconnected to form the high-pressure jet grouting pile anti-seepage wall.

8. The anti-seepage excavation construction method for a percolation water intake project according to any one of claims 1 to 5, characterized in that: The step of excavating the second construction area to form the booster pump station includes: vertically dividing the second construction area into multiple layers of geological bodies according to the design depth of the booster pump station; Constructing a transportation road in the middle of the second construction area that runs through the second construction area; excavating the first layer of geological body in the second construction area except the transportation road; Keeping the height of the end point of the transport road fixed, excavating the transport road until the starting point of the transport road is flush with the bottom of the first geological layer; Repeat the step of excavating the first layer of geological bodies except the transportation road until the starting depth of the transportation road reaches the design depth of the booster pump station; The geological body in the transport road is excavated backwards from the starting point to the end point of the transport road to form the booster pump station.

9. The anti-seepage excavation construction method for infiltration water intake engineering according to claim 8, characterized in that: The step of excavating the first layer of geological body excluding the transport road in the second construction area comprises: excavating the first geological body backwards from the boundary line of the second construction area toward the transportation road; digging a water collection well at the starting point of the transport road; excavating drainage ditches on both sides of said haul road; Safety guardrails are installed on both sides of the transport road.

10. The anti-seepage excavation construction method for a percolation water intake project according to any one of claims 1 to 5, characterized in that: After the step of constructing a flood control cofferdam on a side of the steel sheet pile cut-off wall facing the first construction area along the extension direction of the steel sheet pile cut-off wall, the method further comprises the steps of: The temporary water retaining cofferdam is removed.

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