Deep anti-seepage structure and anti-seepage method for diaphragm wall joints in sandy soil strata

Abstract

The present invention discloses a deep anti-seepage structure and an anti-seepage method for the joints of diaphragm walls in sandy soil strata, which includes an outer vertical pipe and an inner vertical pipe disposed in the outer vertical pipe; a vertical opening is provided on one side of the outer vertical pipe, and the vertical opening can be in contact with the left side and the right side of the joint on the side of the diaphragm wall for excavating the basement; a number of pressure water inlet groups are arranged on the outer vertical pipe in sequence from top to bottom, and each pressure water inlet group includes at least 3 pressure water inlets distributed in a circumferential manner along the cross-section of the outer vertical pipe, and an external drainage pipe is provided between each pressure water inlet and the inner vertical pipe; the present invention has the characteristics of effectively preventing seepage from occurring at the joints of diaphragm walls and avoiding the occurrence of piping.

Description

Technical Field

[0001] The present invention relates to the technical field of diaphragm walls, and in particular to a deep anti-seepage structure and anti-seepage method for the joints of diaphragm walls in sandy soil strata. Background Technique

[0002] Diaphragm walls are commonly used retaining walls for deep foundation pits of basements with 3 floors or more. After the excavation of basements in sandy soil strata, the joints of deep diaphragm walls are prone to serious leakage and piping. Excessive soil erosion will lead to ground collapse and damage to municipal facilities such as roads and pipelines. Such engineering accidents are common and are one of the important hidden dangers affecting urban safety.

[0003] The conventional treatment method is to, after the discovery of leakage during the excavation of the basement, immediately adopt measures such as drainage, rapid-hardening cement or polyurethane internal plugging inside the joints of the diaphragm wall, but often only treat the symptoms rather than the root cause; when the excavation of the basement resumes, the possibility of re-leakage is very high, and it may even cause greater environmental impacts. Summary of the Invention

[0004] The invention purpose of the present invention is to overcome the deficiency that leakage is likely to occur again after the use of the existing leakage treatment methods, and provide a deep anti-seepage structure and anti-seepage method for the joints of diaphragm walls in sandy soil strata.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A deep anti-seepage structure for the joints of diaphragm walls in sandy soil strata includes an outer vertical pipe and an inner vertical pipe arranged in the outer vertical pipe; a vertical opening is provided on one side of the outer vertical pipe, and the vertical opening can contact the left side and the right side of the joint on the side of the diaphragm wall for basement excavation; a number of pressure water inlet groups are arranged on the outer vertical pipe in sequence from top to bottom, and each pressure water inlet group includes at least 3 pressure water inlet holes distributed in a circular pattern along the cross-section of the outer vertical pipe, and an external drainage pipe is provided between each pressure water inlet hole and the inner vertical pipe; a number of staggered drainage holes are provided on both the inner vertical pipe and the external drainage pipe.

[0007] Preferably, the external drainage pipe includes an inner connecting pipe and an outer connecting pipe. All the drainage holes of the external drainage pipe are located on the inner connecting pipe; the inner end of the inner connecting pipe is connected to the inner vertical pipe, the outer end of the inner connecting pipe is connected to the inner end of the outer connecting pipe, and the outer end of the outer connecting pipe is connected to the corresponding pressure water inlet hole; the diameter of the inner connecting pipe is smaller than that of the outer connecting pipe, a spring and a moisture-proof ball are provided in the outer connecting pipe, a sealing cover is provided at the outer end of the outer connecting pipe, the through hole of the sealing cover is in extrusion contact with the moisture-proof ball, and a metal filter screen is provided on the through hole.

[0008] The inner connecting pipe, outer connecting pipe, spring, moisture-proof ball, sealing cover, through hole and metal filter screen are arranged such that when the water pressure is relatively high, the moisture-proof ball is pushed by the water pressure, the spring deforms, the moisture-proof ball moves towards the inner end of the outer connecting pipe, opening the water inlet passage, and water enters the inner vertical pipe. Then, the water flows out through the drain holes on the inner vertical pipe and each of the external drain pipes and enters the outer vertical pipe. The metal filter screen allows water to pass through while preventing other sand and soil particles from passing through, thus ensuring the smoothness of the water inlet passage.

[0009] Preferably, the central angle of the cross-section of the vertically-opening is 90° to 140°; a left elastic sealing plate is provided on the left edge of the vertically-opening, and a right elastic sealing plate is provided on the right edge of the vertically-opening. The cross-sections of the left elastic sealing plate and the right elastic sealing plate are both arc-shaped arching forward. The left edge of the left elastic sealing plate is located behind and to the left of the left edge of the vertically-opening, and the right edge of the right elastic sealing plate is located behind and to the right of the right edge of the vertically-opening.

[0010] The left elastic sealing plate and the right elastic sealing plate are elastic and can deform. When being squeezed, the left edge of the left elastic sealing plate and the right edge of the right elastic sealing plate will be in close contact with the diaphragm wall, thus ensuring the stable performance of the expansive cement in the outer vertical pipe.

[0011] Preferably, two internal drain pipes are provided on the inner vertical pipe, and the outer ends of both internal drain pipes are closed; a number of drain holes are provided on the internal drain pipes and are distributed in a staggered manner.

[0012] The drain holes on the two internal drain pipes can accelerate the outflow of water in the inner vertical pipe to the outside.

[0013] A method for preventing leakage of a deep anti-seepage structure at the joint of a diaphragm wall in sandy soil stratum includes the following steps:

[0014] Step 1, after the diaphragm wall is constructed, an upright hole is excavated in the sandy soil stratum on the side of the diaphragm wall for basement excavation, such that the lower end of the upright hole is flush with the lower end of the diaphragm wall, and the cross-sectional area of the upright hole is twice that of the cross-sectional area of the outer vertical pipe;

[0015] Step 2, place the deep anti-seepage structure in the upright hole, such that the left edge of the vertically-opening contacts the left side of the joint of the diaphragm wall, and the right edge of the vertically-opening contacts the right side of the joint of the diaphragm wall;

[0016] Step 3, fill and compact sandy soil between the edge of the upright hole and the outer vertical pipe, such that the left edge and the right edge of the vertically-opening are squeezed against the diaphragm wall;

[0017] Step 4, fill expansive cement in the outer vertical pipe outside the inner vertical pipe, place a sealing cover on the upper end of the outer vertical pipe, and fixedly connect the sealing cover and the upper end of the outer vertical pipe with concrete.

[0018] After using the anti-seepage method with the deep anti-seepage structure of the present invention, during the excavation of the basement, when more and more water emerges and the water pressure is relatively high, the water pressure pushes open each moisture-proof ball, and the water enters the inner vertical pipe along the outer connecting pipe and the inner connecting pipe of each leakage pipe. The water flows out through each drain hole on the inner vertical pipe and the inner connecting pipe, causing the expansive cement to expand and solidify, effectively preventing seepage from occurring at the joints of the diaphragm wall, making it difficult for soil erosion to occur, and avoiding the damage of municipal facilities and the occurrence of ground collapse.

[0019] Preferably, the central angle of the cross-section of the vertical opening is 90° to 140°; a left elastic sealing plate is provided on the left edge of the vertical opening, and a right elastic sealing plate is provided on the right edge of the vertical opening. The cross-sections of the left elastic sealing plate and the right elastic sealing plate are both arc-shaped arching forward. The left edge of the left elastic sealing plate is located behind the left of the left edge of the vertical opening, and the right edge of the right elastic sealing plate is located behind the right of the right edge of the vertical opening; Steps 2 - 3 are replaced by the following steps:

[0020] Place the deep anti-seepage structure in the vertical hole, so that the left edge of the left elastic sealing plate and the right edge of the right elastic sealing plate are respectively in contact with the left side and the right side of the joint of the diaphragm wall.

[0021] Fill and compact the sand between the edge of the vertical hole and the outer side of the outer vertical pipe. After the left elastic sealing plate and the right elastic sealing plate are deformed by pressure, the left edge of the left elastic sealing plate and the right edge of the left elastic sealing plate are tightly attached to the diaphragm wall; a left vertical cavity is formed at the left part of the joint of the outer vertical pipe, the left elastic sealing plate and the diaphragm wall, and a right vertical cavity is formed at the right part of the joint of the outer vertical pipe, the right elastic sealing plate and the diaphragm wall.

[0022] Inject concrete into the left vertical cavity and the right vertical cavity to stably and sealingly connect the outer vertical pipe with the diaphragm wall.

[0023] When filling and compacting the sand between the edge of the vertical hole and the outer side of the outer vertical pipe, the left elastic sealing plate and the right elastic sealing plate are deformed. A left vertical cavity is formed at the left part of the joint of the outer vertical pipe, the left elastic sealing plate and the diaphragm wall, and a right vertical cavity is formed at the right part of the joint of the outer vertical pipe, the right elastic sealing plate and the diaphragm wall; the concrete in the left vertical cavity and the right vertical cavity stably and sealingly connects the outer vertical pipe with the diaphragm wall, preventing the expansive cement in the outer vertical pipe from getting damp due to the unsealed connection between the outer vertical pipe and the diaphragm wall during the excavation of the basement.

[0024] Therefore, the present invention has the following beneficial effects: It can effectively prevent seepage from occurring at the joints of the diaphragm wall and avoid the occurrence of piping; it makes it difficult for soil erosion to occur and avoids the damage of municipal facilities and the occurrence of ground collapse. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of the present invention;

[0026] Figure 2 This is a top view of the present invention. Detailed implementation manners

[0027] The present invention will be further described below in conjunction with the accompanying drawings and detailed implementation manners.

[0028] As Figure 1 、 Figure 2 The illustrated embodiment is a deep anti-seepage structure for the joint of a diaphragm wall in sandy soil stratum, including an outer vertical pipe 2 and an inner vertical pipe 3 disposed in the outer vertical pipe; a vertical opening is provided on one side of the outer vertical pipe, and the vertical opening can contact the left side and the right side of the joint 41 on the side of the diaphragm wall 4 for excavating the basement; a plurality of pressure water inlet groups are arranged on the outer vertical pipe in sequence from top to bottom, and each pressure water inlet group includes at least 3 pressure water inlet holes 11 distributed in a circumferential manner along the cross-section of the outer vertical pipe. An external drain pipe 12 is provided between each pressure water inlet hole and the inner vertical pipe; a plurality of drain holes are provided on both the inner vertical pipe and the external drain pipe in a staggered manner.

[0029] The external drain pipe includes an inner connecting pipe 121 and an outer connecting pipe 122. Each drain hole of the external drain pipe is located on the inner connecting pipe; the inner end of the inner connecting pipe is connected to the inner vertical pipe, the outer end of the inner connecting pipe is connected to the inner end of the outer vertical pipe, and the outer end of the outer connecting pipe is connected to the corresponding pressure water inlet hole; the diameter of the inner connecting pipe is smaller than that of the outer connecting pipe. A spring 123 and a moisture-proof ball 124 are provided in the outer connecting pipe. A sealing cover 125 is provided at the outer end of the outer connecting pipe. The through hole 1251 of the sealing cover is in pressing contact with the moisture-proof ball, and a metal filter screen is provided on the through hole.

[0030] The central angle of the cross-section of the vertical opening is 140°; a left elastic sealing plate 61 is provided on the left edge of the vertical opening, and a right elastic sealing plate 62 is provided on the right edge of the vertical opening. The cross-sections of the left elastic sealing plate and the right elastic sealing plate are both in an arc shape arched forward. The left edge of the left elastic sealing plate is located behind the left of the left edge of the vertical opening, and the right edge of the right elastic sealing plate is located behind the right of the right edge of the vertical opening.

[0031] Two internal drain pipes 7 are provided on the inner vertical pipe, and the outer ends of both internal drain pipes are closed; a plurality of drain holes are provided on the internal drain pipes in a staggered manner.

[0032] An anti-seepage method for a deep anti-seepage structure of a joint of a diaphragm wall in sandy soil stratum is characterized by including the following steps:

[0033] Step 1, after the diaphragm wall is constructed, a vertical hole 1 is excavated in the sandy soil stratum on the side of the diaphragm wall for excavating the basement, so that the lower end of the vertical hole is flush with the lower end of the diaphragm wall, and the cross-sectional area of the vertical hole is 2 times the cross-sectional area of the outer vertical pipe;

[0034] Step 2: Place a deep anti-seepage structure in the vertical hole, such that the left edge of the left elastic sealing plate and the right edge of the right elastic sealing plate are respectively in contact with the left side and the right side of the joint of the diaphragm wall.

[0035] Step 3: Fill the space between the edge of the vertical hole and the outer side of the outer vertical pipe with sand 5 and compact it. After the left elastic sealing plate and the right elastic sealing plate are deformed by the pressure, the left edge of the left elastic sealing plate and the right edge of the left elastic sealing plate are pressed against the diaphragm wall; a left vertical cavity is formed at the left part of the joint between the outer vertical pipe, the left elastic sealing plate and the diaphragm wall, and a right vertical cavity is formed at the right part of the joint between the outer vertical pipe, the right elastic sealing plate and the diaphragm wall.

[0036] Step 4: Inject concrete into the left vertical cavity and the right vertical cavity to stably and sealingly connect the outer vertical pipe to the diaphragm wall.

[0037] When filling the space between the edge of the vertical hole and the outer side of the outer vertical pipe with sand and compacting it, the left elastic sealing plate and the right elastic sealing plate are deformed. A left vertical cavity is formed at the left part of the joint between the outer vertical pipe, the left elastic sealing plate and the diaphragm wall, and a right vertical cavity is formed at the right part of the joint between the outer vertical pipe, the right elastic sealing plate and the diaphragm wall; the concrete in the left vertical cavity and the right vertical cavity stably and sealingly connects the outer vertical pipe to the diaphragm wall, preventing the expansive cement in the outer vertical pipe from being affected by moisture due to poor sealing between the outer vertical pipe and the diaphragm wall during the excavation of the basement.

[0038] Step 5: Fill the outer vertical pipe outside the inner vertical pipe with expansive cement, place a sealing cover on the upper end of the outer vertical pipe, and fixedly connect the sealing cover and the upper end of the outer vertical pipe with concrete.

[0039] During the excavation of the basement, when more and more water comes out and the water pressure is relatively high, the water pressure pushes open each moisture-proof ball, and the water enters the inner vertical pipe along the outer connecting pipes and the inner connecting pipes of each water leakage pipe. Then the water flows out through the two inner water leakage pipes, the inner vertical pipe and the water leakage holes on the inner connecting pipes, causing the expansive cement in the outer vertical pipe to expand and solidify, effectively preventing water leakage from occurring at the joint of the diaphragm wall, making it not easy for soil erosion to occur, and avoiding the damage of municipal facilities and the occurrence of ground collapse.

[0040] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A deep anti-seepage structure for the joints of diaphragm walls in sandy soil strata, Characterized in that, It includes an outer vertical pipe (2) and an inner vertical pipe (3) arranged in the outer vertical pipe; a vertical opening is provided on one side of the outer vertical pipe, and the vertical opening can be in contact with the left side and the right side of the joint (41) on the side of the diaphragm wall (4) for excavating the basement; several groups of pressure water inlets are arranged on the outer vertical pipe in sequence from top to bottom, and each group of pressure water inlets includes at least 3 pressure water inlet holes (11) distributed in a circular pattern along the cross-section of the outer vertical pipe, and an external drainage pipe (12) is provided between each pressure water inlet hole and the inner vertical pipe; several drain holes are arranged on both the inner vertical pipe and the external drainage pipe in a staggered manner; the external drainage pipe includes an inner connecting pipe (121) and an outer connecting pipe (122), and all the drain holes of the external drainage pipe are located on the inner connecting pipe; the inner end of the inner connecting pipe is connected to the inner vertical pipe, the outer end of the inner connecting pipe is connected to the inner end of the outer connecting pipe, and the outer end of the outer connecting pipe is connected to the corresponding pressure water inlet hole; the diameter of the inner connecting pipe is smaller than that of the outer connecting pipe, a spring (123) and a moisture-proof ball (124) are arranged in the outer connecting pipe, a sealing cover (125) is provided on the outer end of the outer connecting pipe, the through hole (1251) of the sealing cover is in extrusion contact with the moisture-proof ball, and a metal filter screen is provided on the through hole; the central angle of the cross-section of the vertical opening is 90° to 140°; a left elastic sealing plate (61) is provided on the left edge of the vertical opening, and a right elastic sealing plate (62) is provided on the right edge of the vertical opening. The cross-sections of the left elastic sealing plate and the right elastic sealing plate are both arc-shaped arching forward. The left edge of the left elastic sealing plate is located behind the left of the left edge of the vertical opening, and the right edge of the right elastic sealing plate is located behind the right of the right edge of the vertical opening.

2. The deep anti-seepage structure for the joints of diaphragm walls in sandy soil strata according to claim 1, Characterized in that, Two internal drainage pipes (7) are provided on the inner vertical pipe, and the outer ends of the two internal drainage pipes are both closed; several drain holes are arranged on the internal drainage pipes in a staggered manner.

3. An anti-seepage method based on the deep anti-seepage structure for the joints of diaphragm walls in sandy soil strata according to claim 1, Characterized in that, It includes the following steps: Step 1, after the diaphragm wall is constructed, an upright hole (1) is excavated in the sandy soil strata on the side of the diaphragm wall for excavating the basement, so that the lower end of the upright hole is flush with the lower end of the diaphragm wall, and the cross-sectional area of the upright hole is 2 times the cross-sectional area of the outer vertical pipe; Step 2, place the deep anti-seepage structure in the upright hole, so that the left edge of the vertical opening is in contact with the left side of the joint of the diaphragm wall, and the right edge of the vertical opening is in contact with the right side of the joint of the diaphragm wall; Step 3, fill and compact the sandy soil (5) between the edge of the upright hole and the outer vertical pipe, so that the left edge and the right edge of the vertical opening are extruded against the diaphragm wall; Step 4, fill the outer vertical pipe outside the inner vertical pipe with expansive cement, place a sealing cover on the upper end of the outer vertical pipe, and fixedly connect the sealing cover and the upper end of the outer vertical pipe with concrete.

4. The anti-seepage method for the deep anti-seepage structure of the joints of diaphragm walls in sandy soil strata according to claim 3, Characterized in that, Steps 2 - 3 are replaced by the following steps: Place a deep anti-seepage structure in the vertical hole, so that the left edge of the left elastic sealing plate and the right edge of the right elastic sealing plate are respectively in contact with the left side and the right side of the joint of the diaphragm wall; Fill and compact the sand between the edge of the vertical hole and the outer side of the outer vertical pipe. After the left elastic sealing plate and the right elastic sealing plate are deformed by pressure, the left edge of the left elastic sealing plate and the right edge of the left elastic sealing plate are closely attached to the diaphragm wall; A left vertical cavity is formed at the left part of the joint of the outer vertical pipe, the left elastic sealing plate and the diaphragm wall, and a right vertical cavity is formed at the right part of the joint of the outer vertical pipe, the right elastic sealing plate and the diaphragm wall; Inject concrete into the left vertical cavity and the right vertical cavity to stably seal and connect the outer vertical pipe with the diaphragm wall.

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