A foundation pit dewatering method and a side slope supporting device suitable for high water level areas

Abstract

This invention relates to the field of construction technology, and more specifically, to a method for dewatering foundation pits and a slope support device suitable for high water level areas. The method includes using Ferencius's 4.5H method (empirical method) to determine the most dangerous sliding surface of a uniform soil slope, calculating the volumetric water content of the soil on the sliding surface, and obtaining the stability coefficient K of any soil strip on the sliding surface according to the Swedish slice method. m The calculation expression is obtained by substituting the design parameters of the foundation pit into equation (3) and comparing the calculation results to see if they meet the requirements. If they do not meet the requirements, the groundwater level is lowered and the calculation is repeated until the requirements are met. The difference between the groundwater level depth and the original groundwater level depth is the dewatering depth. This invention proposes a new method for calculating foundation pit dewatering and adopts two methods: simultaneous drilling and protection, and simultaneous excavation and protection. This improves the construction speed, accelerates the construction process, and ensures the stability of the foundation pit slope.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and more specifically, to a method for dewatering foundation pits and a slope support device suitable for areas with high water levels. Background Technology

[0002] A high groundwater level results in a high moisture content in the surface soil and weak matric suction between soil particles. Under these geological conditions, excavation of the foundation pit will be very difficult and prone to slope instability. Furthermore, construction of foundation pits with high groundwater levels requires prolonged dewatering, and the dewatering process is highly susceptible to borehole collapse. These factors significantly impact construction progress, quality, and project cost.

[0003] To address the above situation, this invention proposes a method for dewatering and protecting foundation pits in areas with high water levels. This invention employs two methods: simultaneous drilling and protection, and simultaneous excavation and protection. Simultaneous drilling and protection ensures drilling quality and improves construction speed. The simultaneous excavation and protection method accelerates construction, ensures the stability of the foundation pit slope, and utilizes the excavated soil, offering both economic and environmental advantages. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, a method for dewatering foundation pits and a slope support device suitable for high water level areas are provided.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A method for dewatering foundation pits in areas with high water levels includes:

[0007] S1. Using Fernando's 4.5H method (empirical method), the most dangerous sliding surface of a uniform soil slope is determined. The most dangerous sliding surface passes through the toe of the slope, with a total length of W and a total height of H. H is expressed as a curve function of W, with W represented by x and H by y on the coordinate axes. The curve function is: ;

[0008] S2. Divide the sliding surface into i transverse soil strips according to its average width, then The soil strips are divided into j longitudinal strips according to their average height, from lowest to highest as follows: The moisture content of soil strips in the same longitudinal direction is considered to be the same; in the process of division, the part in contact with the sliding surface is divided into H1, and the slope part is divided into H2. j ;

[0009] The soil moisture content below the groundwater level is considered saturated. The volumetric moisture content of the soil above the groundwater level is:

[0010] (1);

[0011] In the formula: This refers to the volumetric water content of the soil. This refers to the saturated volumetric water content of the soil. Let α be the residual volumetric water content of the soil, and α be the fitting parameter for the soil-water characteristic curve. Where ξ is the matrix suction head, , Where is the groundwater level depth, and h is the distance from any point on the sliding surface to the top of the pit. ;

[0012] S3. According to formula (1), the longitudinal moisture content of any soil strip from low to high is θ1, θ2…θ j The stability coefficient K of any soil strip on the sliding surface is obtained according to the Swedish slice method. m Calculate the expression:

[0013] (2);

[0014] In the formula: β is the slope of the foundation pit, c' and φ' are the effective cohesion and effective internal friction angle, and l m ρ is the length of the soil on the sliding surface. s and ρ w These are the densities of soil and water, respectively, in N. m T is the reaction force of the normal stress. m The shear resistance of the soil at the sliding surface;

[0015] The stability coefficient K of the foundation pit slope can be expressed as:

[0016] (3);

[0017] S4. Substitute the design parameters of the foundation pit into formula (3) for calculation, compare the calculation results to see if they meet the requirements. If they do not meet the requirements, lower the groundwater level and calculate again until they meet the requirements. At this time, the difference between the groundwater level depth and the original groundwater level depth is the dewatering depth.

[0018] Preferably, it also includes: S5, performing dewatering of the foundation pit:

[0019] S51. Determine the location of the dewatering wells:

[0020] The radius of influence of precipitation is:

[0021] (4);

[0022] In the formula: Δh is the precipitation depth, k is the soil permeability coefficient, and H' is the groundwater depth of the precipitation portion;

[0023] Dewatering wells are installed inside and outside the foundation pit. The installation range and number of dewatering wells are determined according to formula (4). The overall range of the dewatering wells must cover the entire foundation pit.

[0024] Preferably, step S5 further includes:

[0025] S52. Install protective devices for dewatering wells:

[0026] Drilling is performed using a drilling device:

[0027] Drill a hole once. After drilling a hole once, press the top cylindrical structure into the hole tightly against the edge of the hole and remove the excess soil from the hole. The size of the hole is the same as the cross-sectional size of the top cylindrical structure.

[0028] Secondary drilling was performed. After the secondary drilling was completed, a second cylindrical structure was inserted, and excess soil was removed.

[0029] Drill holes multiple times until the entire cylindrical structure is inserted;

[0030] S53. After the dewatering well is installed, pump water. Place the end of the pumping pipe on the filter screen of the bottom cylindrical structure. During pumping, cover the bottom of the dewatering well to prevent debris from entering the well.

[0031] Preferably, in step S52, the connecting portion between adjacent cylindrical structures is sprayed with mortar.

[0032] Preferably, it also includes S6, foundation pit slope protection:

[0033] S61. When the dewatering depth of the foundation pit meets the conditions for the excavation of the first-level slope, the first-level slope excavation shall be carried out first, and the foundation pit dewatering work shall continue. When excavating, the boundary soil of the foundation pit shall be excavated first. When the excavation width reaches the width of the hollow concrete hexahedron structure, the hexahedron structure shall be placed in the pit. The hexahedron structure shall be closely attached to the side wall of the foundation pit, and the bottom shall be inserted into the soil to improve its stability.

[0034] S62. After placing the hexahedral structure, fill the excavated soil into the structure. The filling height is the height of the large circular hole of the hexahedral structure.

[0035] S63. After the backfilling is completed, a structural cap shall be added to prevent rain and debris from entering the soil and affecting the construction effect. After the structural cap is added, the excavated soil shall be piled up in front of the structure and compacted to form a slope.

[0036] S64. After the structural work and soil piling work are completed, spray grouting is carried out on the surface of the soil piling.

[0037] Preferably, the drilling device includes a drill bit, a drill rod, and a rod cap, which are fixedly connected by a screw and a nut, and the drill rod consists of one or more short drill rods.

[0038] Preferably, the rainwater well protection device includes a top cylindrical structure, a middle cylindrical structure, a secondary bottom cylindrical structure, and a bottom cylindrical structure arranged sequentially from top to bottom; the bottom cylindrical structure has a permeable stone bottom, a concrete body with fine pores, and a fine pore filter screen at the top; the secondary bottom cylindrical structure has a concrete body with small round pores; the top cylindrical structure and the middle cylindrical structure have no pores in their bodies;

[0039] The intermediate cylindrical structure is configured as one or more.

[0040] The present invention also discloses a foundation pit slope support device, including a hollow concrete hexahedron structure, wherein the front end face and the rear end face of the hollow concrete hexahedron structure are both planar, the rear end face is a solid structure, and the front end face is provided with a through hole connecting the inner cavity of the hollow concrete hexahedron structure, the through hole being inclined downward; the hollow concrete hexahedron structure (3) has a large circular hole (35) at the top.

[0041] The hollow concrete hexahedral structure has a convex semicircle on the left side and a concave semicircle on the right side.

[0042] The lower side of the hollow concrete hexahedron structure is a sloping concrete surface, and the lower end of the sloping concrete surface is connected to a raised solid concrete. The upper end of the hollow concrete hexahedron structure is provided with an opening that matches the raised solid concrete.

[0043] Preferably, the hollow concrete hexahedron structure is provided in multiple ways, and also includes a structural cap, which fits into the opening of the uppermost hollow concrete hexahedron structure.

[0044] The beneficial effects of this invention compared to the prior art are as follows:

[0045] This invention proposes a novel method for calculating foundation pit dewatering and employs two approaches: simultaneous drilling and protection, and simultaneous excavation and protection. The simultaneous drilling and protection approach ensures drilling quality and improves construction speed. The simultaneous excavation and protection method accelerates construction, ensures the stability of the foundation pit slope, and utilizes the excavated soil, offering both economic and environmental advantages. Attached Figure Description

[0046] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0047] Figure 1 This is a schematic diagram of the slope sliding surface;

[0048] Figure 2This is an exploded view of the drilling equipment;

[0049] Figure 3 This is a schematic diagram of the drilling device;

[0050] Figure 4 A schematic diagram of the exploded protective device for dewatering wells;

[0051] Figure 5 Schematic diagram of a protective device for a dewatering well;

[0052] Figure 6 Schematic diagram of hollow concrete hexahedral structure and structural cap structure;

[0053] Figure 7 This is a schematic diagram of the assembly of a hollow concrete hexahedral structure.

[0054] In the diagram: 1-Drilling device, 11-Drill bit, 12-Drill rod, 13-Rod cap, 14-Screw, 2-Drainage well protection device, 21-Top cylindrical structure, 22-Middle cylindrical structure, 23-Secondary bottom cylindrical structure, 24-Bottom cylindrical structure, 3-Hollow concrete hexahedral structure, 31-Through hole, 32-Sloped concrete surface, 33-Protruding solid concrete, 34-Opening, 35-Large round hole, 4-Structural cap. Detailed Implementation

[0055] 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, and 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.

[0056] Example 1:

[0057] like Figures 1 to 7 As shown, a method for dewatering foundation pits in areas with high water levels includes:

[0058] S1. Using Ferlenius's 4.5H method (empirical method), the most dangerous sliding surface of a uniform soil slope is determined. The most dangerous sliding surface is defined as passing through the toe of the slope, with a total length of W and a total height of H. H can be expressed as a curve function of W. In the coordinate system, W is represented by x, and H by y. The curve function is: ;

[0059] S2, such as Figure 1 As shown, if the sliding surface is divided into i transverse soil strips according to its average width, then... In the diagram, 'a' represents the left endpoint of any soil strip on the x-axis, 'b' represents the right endpoint, and 'ba' = 'w'. The height of the left side of the soil strip is h1, and the height of the right side is h2. For simplified calculation, the soil strip is divided into j longitudinal sections according to its average height, from lowest to highest: The moisture content of soil strips in the same longitudinal direction is considered to be the same; in the process of division, the part in contact with the sliding surface is divided into H1, and the slope part is divided into H2. j ;

[0060] When a portion of the sliding surface is below the groundwater level, the water content of that portion of the soil is considered the saturated soil water content. The volumetric water content of the soil above the groundwater level is:

[0061] (1);

[0062] In the formula: This refers to the volumetric water content of the soil. This refers to the saturated volumetric water content of the soil. Let α be the residual volumetric water content of the soil, and α be the fitting parameter for the soil-water characteristic curve. Where ξ is the matrix suction head, , Where is the groundwater level depth, and h is the distance from any point on the sliding surface to the top of the pit. .

[0063] S3. According to formula (1), the longitudinal moisture content of any soil strip from low to high is θ1, θ2…θ j The stability coefficient K of any soil strip on the sliding surface is obtained according to the Swedish slice method. m Calculate the expression:

[0064] (2);

[0065] In the formula: β is the slope of the foundation pit, c' and φ' are the effective cohesion and effective internal friction angle, and l m ρ is the length of the soil on the sliding surface. s and ρ w These are the densities of soil and water, respectively, in N. m T is the reaction force of the normal stress. m The shear resistance of the soil at the sliding surface;

[0066] The stability coefficient K of the foundation pit slope can be expressed as:

[0067] (3);

[0068] S4. Substitute the design parameters of the foundation pit into formula (3) for calculation, compare the calculation results to see if they meet the requirements of national and local regulations. If they do not meet the requirements, carry out foundation pit dewatering to lower the groundwater level and calculate again until they meet the requirements. At this time, the difference between the groundwater level depth and the original groundwater level depth is the dewatering depth.

[0069] S5. Carry out dewatering of the foundation pit:

[0070] S51. Determine the location of the dewatering wells:

[0071] The radius of influence of precipitation is:

[0072] (4);

[0073] In the formula: Δh is the precipitation depth, k is the soil permeability coefficient, and H' is the groundwater depth of the precipitation portion;

[0074] According to the precipitation requirements, dewatering wells are set up inside and outside the foundation pit. The range and number of dewatering wells are determined according to formula (4). The overall range of the dewatering wells must cover the entire foundation pit.

[0075] S52. Install protective devices for dewatering wells:

[0076] like Figure 4 , Figure 5 As shown, the rainwater well protection device is assembled from multiple prefabricated cylindrical structures. The upper part of the cylindrical structure is shaped like a cap, and the bottom is cylindrical. Specifically, the rainwater well protection device 2 includes a top cylindrical structure 21, a middle cylindrical structure 22, a second-bottom cylindrical structure 23, and a bottom cylindrical structure 24 arranged sequentially from top to bottom. The bottom cylindrical structure 24 has a permeable stone bottom, a concrete body with numerous fine holes, and a fine-mesh filter at the top. The second-bottom cylindrical structure 23 has a concrete body with numerous small round holes. The top cylindrical structure 21 and the middle cylindrical structure 22 have no holes in their bodies. The cap-shaped part of the topmost cylindrical structure is much larger than the other cylindrical structures to extend above the ground and prevent debris from entering the rainwater well. There are one or more middle cylindrical structures 22.

[0077] Drilling is performed using a drilling device:

[0078] Drill a hole in one go, reaching a height close to that of the top cylindrical structure. After drilling is completed, press the top cylindrical structure 21 into the hole tightly against the edge of the hole, and remove any excess soil from the hole. The size of the hole is the same as the cross-sectional size of the top cylindrical structure. The top cylindrical structure is higher than the ground to ensure that debris cannot enter the hole.

[0079] A second borehole is drilled, and after the second borehole is completed, the second layer of cylindrical structure is placed in, and excess soil is removed. This process is repeated for all cylindrical structures. To connect the different cylindrical structures, the connecting parts are grouted to ensure the integrity of the structure.

[0080] like Figure 3 As shown, the drilling device 1 includes a drill bit 11, a drill rod 12, and a rod cap 13. The drill bit 11, the drill rod 12, and the rod cap 13 are fixedly connected by a screw 14 and a nut. The drill rod 12 is composed of one or more short drill rods.

[0081] like Figure 2 As shown, the drill bit 11, drill rod 12, and rod cap 13 can adopt the following structure: the bottom of the drill bit is conical, with four metal cutting edges evenly distributed around the cone; the top of the drill bit is a raised cylindrical tube with a central hole for screws to pass through. The top of the drill rod is a hollow cylindrical tube with a central hole for screws to pass through; the bottom of the drill rod is a solid metal rod with a central hole for screws to pass through. The bottom of the rod cap is a hollow cylindrical tube with a central hole for screws to pass through. The center of the rod cap is a disc-shaped metal cap with four central holes, which are the insertion holes used for screwing drill rods into the soil. The top of the rod cap is a ring, which serves as the force-bearing part when pulling the drill rod out of the soil. The fixing part consists of a screw, a nut, and a metal washer. The screw passes through the central hole, fits into the washer, and connects to the nut. The nut has a cross-shaped surface to facilitate tightening of the nut and screw, ensuring a secure connection between the components.

[0082] S53. After the dewatering well is installed, pump water. Place the end of the pumping pipe on the filter screen of the bottom cylindrical structure. During pumping, cover the bottom of the dewatering well to prevent debris from entering the well.

[0083] S6. Excavation pit slope protection:

[0084] Step 1: When the dewatering depth of the foundation pit meets the conditions for excavation of the first-level slope, proceed with the first-level slope excavation and continue the dewatering work. During excavation, first excavate the soil at the boundary of the foundation pit. When the excavation width reaches the width of the hollow concrete hexahedron structure, place the hexahedron structure inside. The hexahedron is placed tightly against the sidewall of the foundation pit, and soil is inserted at the bottom to improve its stability.

[0085] Step 2: After placing the hexahedral structure, fill the excavated soil into the structure, with the filling height based on the height of the large circular hole.

[0086] Step 3: After backfilling, a structural cap is installed to prevent rainwater and debris from entering the soil and affecting the construction results. After installing the structural cap, the excavated soil is piled up in front of the structure and compacted to form a slope. This soil piling not only improves slope stability but also facilitates the use of the excavated soil, improving the construction site environment and achieving resource utilization of the excavated soil.

[0087] Step 4: After the structural work and soil piling are completed, shotcrete is applied to the surface of the soil piling. Shotcrete improves the stability of the slope and also suppresses dust from the soil piling, which is beneficial to environmental protection at the construction site.

[0088] Example 2:

[0089] like Figure 6 , Figure 7 As shown, a foundation pit slope protection device is used for foundation pit slope protection work in Example 1. Specifically, it includes a hollow concrete hexahedral structure 3. The hollow structure is designed to fill the excavated soil, which utilizes the excavated soil, thus benefiting environmental protection. Furthermore, the added soil increases the self-weight of the structure, which helps improve the stability of the foundation pit slope. The hexahedral structure has a large circular hole at the top, designed to facilitate the hoisting of the structure.

[0090] The front and rear faces of the hollow concrete hexahedron structure 3 are both planar, while the rear face is a solid structure. The front face is provided with a through hole 31 that connects to the inner cavity of the hollow concrete hexahedron structure. The through hole 31 is inclined downward to drain water from the hexahedron structure.

[0091] The hollow concrete hexahedral structure has a convex semicircle on the left side and a concave semicircle on the right side, allowing the two structures to be joined together. Because the joint is semicircular, the joint angle can be freely adjusted, enabling the semicircular design to meet the requirements of irregular foundation pit plan shapes.

[0092] The lower side of the hollow concrete hexahedron structure 3 is a sloping concrete surface 32, and the lower end of the sloping concrete surface 32 is connected to a raised solid concrete section 33. The upper end of the hollow concrete hexahedron structure 3 has an opening 34 that mates with the raised solid concrete section 33. The raised solid concrete section 33 can be inserted into the opening 34, and this design can meet the different depth requirements of the foundation pit excavation.

[0093] Multiple hollow concrete hexahedral structures 3 are provided, and the structural caps are matched with the opening 34 of the uppermost hollow concrete hexahedral structure 3.

[0094] The above description only illustrates the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention, and all such changes should be included within the protection scope of the present invention.

Claims

1. A method for dewatering foundation pits in areas with high water levels, characterized in that, include: S1. Using Ferlenius's 4.5H method, the most dangerous sliding surface of a uniform soil slope is determined. The most dangerous sliding surface passes through the toe of the slope, with a total length of W and a total height of H. H is expressed as a curve function of W, with W represented by x and H by y on the coordinate axes. The curve function is: ; S2. Divide the sliding surface into i transverse soil strips according to its average width, then The soil strips are divided into j longitudinal strips according to their average height, from lowest to highest as follows: The moisture content of soil strips in the same longitudinal direction is considered to be the same; In the process of division, the part in contact with the sliding surface is assigned to H1, and the slope part is assigned to H2. j ; The soil moisture content below the groundwater level is considered saturated. The volumetric moisture content of the soil above the groundwater level is: （1）； In the formula: This refers to the volumetric water content of the soil. This refers to the saturated volumetric water content of the soil. Let α be the residual volumetric water content of the soil, and α be the fitting parameter for the soil-water characteristic curve. Where ξ is the matrix suction head, , Where is the groundwater level depth, and h is the distance from any point on the sliding surface to the top of the pit. ; S3. According to formula (1), the longitudinal moisture content of any soil strip from low to high is θ1, θ2...θ j The stability coefficient K of any soil strip on the sliding surface is obtained according to the Swedish slice method. m Calculate the expression: （2）； In the formula: β is the slope of the foundation pit, c' and φ' are the effective cohesion and effective internal friction angle, and l m ρ is the length of the soil on the sliding surface. s and ρ w These are the densities of soil and water, respectively, in N. m The reaction force of the normal stress, T m Let be the shear resistance of the soil on the sliding surface, 'a' be the left end point of any soil strip on the x-axis, 'b' be the right end point, and 'ba' = 'w'; the height of the left side of the soil strip is h1, and the height of the right side of the soil strip is h2. The stability coefficient K of the foundation pit slope can be expressed as: （3）； S4. Substitute the design parameters of the foundation pit into formula (3) for calculation, compare the calculation results to see if they meet the requirements. If they do not meet the requirements, lower the groundwater level and calculate again until they meet the requirements. At this time, the difference between the groundwater level depth and the original groundwater level depth is the dewatering depth. S5. Carry out dewatering of the foundation pit: S51. Determine the location of the dewatering wells: The radius of influence of precipitation is: （4）； In the formula: Δh is the precipitation depth, k is the soil permeability coefficient, and H' is the groundwater depth of the precipitation portion; Dewatering wells are installed inside and outside the foundation pit. The installation range and number of dewatering wells are determined according to formula (4). The overall range of the dewatering wells must cover the entire foundation pit. S52. Install protective devices for dewatering wells: Drilling is performed using a drilling device: Drill a hole once. After drilling a hole once, press the top cylindrical structure into the hole tightly against the edge of the hole and remove the excess soil from the hole. The size of the hole is the same as the cross-sectional size of the top cylindrical structure. Secondary drilling was performed. After the secondary drilling was completed, a second cylindrical structure was inserted, and excess soil was removed. Drill holes multiple times until the entire cylindrical structure is inserted; S53. After the dewatering well is installed, pump water. Place the end of the pumping pipe on the filter screen of the bottom cylindrical structure. During pumping, cover the bottom of the dewatering well to prevent debris from entering the well. S6. Excavation pit slope protection: S61. When the dewatering depth of the foundation pit meets the conditions for the excavation of the first-level slope, the first-level slope excavation shall be carried out first, and the foundation pit dewatering work shall continue. When excavating, the boundary soil of the foundation pit shall be excavated first. When the excavation width reaches the width of the hollow concrete hexahedron structure, the hexahedron structure shall be placed in the pit. The hexahedron structure shall be closely attached to the side wall of the foundation pit, and the bottom shall be inserted into the soil to improve its stability. S62. After placing the hexahedral structure, fill the excavated soil into the structure. The filling height is the height of the large circular hole of the hexahedral structure. S63. After the backfilling is completed, a structural cap shall be added to prevent rain and debris from entering the soil and affecting the construction effect. After the structural cap is added, the excavated soil shall be piled up in front of the structure and compacted to form a slope. S64. After the structural work and soil piling work are completed, spray grouting is carried out on the surface of the soil piling.

2. The method for dewatering foundation pits in high-water-level areas according to claim 1, characterized in that: In step S52, spraying is performed on the connecting portion between adjacent cylindrical structures.

3. The method for dewatering foundation pits in high-water-level areas according to claim 1, characterized in that: The drilling device (1) includes a drill bit (11), a drill rod (12) and a rod cap (13). The drill bit (11), the drill rod (12) and the rod cap (13) are fixedly connected by a screw (14) and a nut. The drill rod (12) is composed of one or more short drill rods.

4. The method for dewatering foundation pits in high-water-level areas according to claim 1, characterized in that: The rainwater well protection device (2) includes a top cylindrical structure (21), a middle cylindrical structure (22), a sub-bottom cylindrical structure (23), and a bottom cylindrical structure (24) arranged sequentially from top to bottom; the bottom cylindrical structure (24) has a permeable stone bottom, a concrete body with fine pores, and a fine pore filter screen at the top; the sub-bottom cylindrical structure (23) has a concrete body with small round pores; the top cylindrical structure (21) and the middle cylindrical structure (22) have no pores in their bodies; The intermediate cylindrical structure (22) is configured as one or more.

5. The method for dewatering foundation pits in high-water-level areas according to claim 1, characterized in that: The hollow concrete hexahedron structure (3) includes a front and rear face of the hollow concrete hexahedron structure (3) which are both planar, and the rear face is a solid structure. The front face is provided with a through hole (31) that connects to the inner cavity of the hollow concrete hexahedron structure. The through hole (31) is inclined downward. The top of the hollow concrete hexahedron structure (3) has a large circular hole (35). The hollow concrete hexahedral structure (3) has a convex semicircle on the left side and a concave semicircle on the right side. The lower side of the hollow concrete hexahedron structure (3) is a sloping concrete surface (32), and the lower end of the sloping concrete surface (32) is connected to a raised solid concrete (33). The upper end of the hollow concrete hexahedron structure (3) is provided with an opening (34) that matches the raised solid concrete (33).

6. A method for dewatering foundation pits in high-water-level areas according to claim 5, characterized in that: The hollow concrete hexahedral structure (3) is provided in multiple ways, and also includes a structural cap (4), which is matched with the opening (34) of the uppermost hollow concrete hexahedral structure (3).

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