Reinforcing structure for defect area of pre-constructed diaphragm wall and construction method of reinforcing structure

Abstract

The invention relates to a reinforcing structure for a defect area of a pre-constructed diaphragm wall and a construction method of the reinforcing structure, the defect area is located on the side, close to a post-constructed diaphragm wall, of the pre-constructed diaphragm wall, the setting direction of the post-constructed diaphragm wall intersects with the setting direction of the pre-constructed diaphragm wall, and the end of the post-constructed diaphragm wall is arranged close to the defect area. The reinforcing structure comprises a plurality of cast-in-situ bored piles arranged on the side, away from the foundation pit, of the defect area in a driving mode in the arrangement direction of the post-construction diaphragm wall, and part of the cast-in-situ bored piles are located on the side, away from the foundation pit, of the post-construction diaphragm wall. The multiple MJS construction method piles are arranged on the side, close to the foundation pit, of the defect area and the side, away from the foundation pit, of the defect area in a driving mode, and every two adjacent MJS construction method piles are partially overlapped. The cast-in-situ bored pile is combined with the MJS construction method pile to reinforce the defect area, the risk caused by removing the defects in the defect area is avoided, the problem of supporting and water stopping is effectively solved, the enclosure replacement effect is good, and site construction is convenient.

Description

Technical Field

[0001] The invention relates to the field of foundation pit support construction engineering, and in particular to a reinforcement structure for first constructing a defective area of ​​a ground-connected wall and a construction method thereof. Background Art

[0002] Underground continuous walls are constructed for water interception, soil retention and load-bearing. As the urban construction environment becomes increasingly complex, their applications are becoming more and more extensive. Their main features are high strength, high rigidity and good water-stopping effect.

[0003] When the foundation pit is close to the subway, in order to avoid interference with the adjacent buildings, the ground-anchored wall on the side close to the subway is constructed first, and then the ground-anchored walls on the other sides are constructed, and then they can be connected with the ground-anchored wall constructed first. During the trenching process of the later-constructed ground-anchored wall, it was found that the first-constructed ground-anchored wall had a structure protruding into the foundation pit 7m below the surface, which brought trouble to the later-constructed ground-anchored wall. The traditional approach is to first remove the structure protruding into the foundation pit formed by the first-constructed ground-anchored wall, and then construct the later-constructed ground-anchored wall. However, since the cause of the protruding structure cannot be determined, if it is removed, it is likely to cause damage to the first-constructed ground-anchored wall, which will lead to more quality and safety risks. Therefore, a new solution is urgently needed. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a reinforcement structure and a construction method for the defective area of ​​the ground-connected wall constructed in advance, so as to solve the problem that the removal of the protruding structure formed by the defects in the prior art may cause damage to the ground-connected wall structure and thus cause quality and safety risks.

[0005] The technical solution to achieve the above purpose is:

[0006] The present invention provides a reinforcement structure for a defective area of ​​a first-constructed ground diaphragm wall, wherein the defective area is located on a side of the first-constructed ground diaphragm wall close to a later-constructed ground diaphragm wall, the later-constructed ground diaphragm wall intersects with the setting direction of the first-constructed ground diaphragm wall, and the end of the later-constructed ground diaphragm wall is arranged close to the defective area. The reinforcement structure comprises:

[0007] A plurality of bored cast-in-place piles are driven along the setting direction of the post-construction ground connection wall on the side of the defective area away from the foundation pit, with some of the bored cast-in-place piles being located on the side of the post-construction ground connection wall away from the foundation pit;

[0008] A plurality of MJS construction method piles are driven in the defective area on the side close to the foundation pit and the side far from the foundation pit, and two adjacent MJS construction method piles are partially overlapped.

[0009] A further improvement of the reinforcement structure of the defective area of ​​the ground-connected wall constructed first in the present invention is that the MJS construction method piles located on the side of the defective area far away from the foundation pit are partially overlapped with the bored cast-in-place piles.

[0010] A further improvement of the reinforcement structure of the defective area of ​​the first constructed ground diaphragm wall of the present invention is that a top pressure beam is provided on the top of the later constructed ground diaphragm wall and the top of the first constructed ground diaphragm wall, and the corresponding part of the top pressure beam is located at the defective area.

[0011] A further improvement of the reinforcement structure of the defective area of ​​the first constructed ground-connected wall of the present invention is that it also includes a plurality of support beams arranged at intervals along the height direction of the inner wall of the foundation pit, one end of the support beam extends into the first constructed ground-connected wall for anchoring, and the other end of the support beam extends into the later constructed ground-connected wall for anchoring.

[0012] A further improvement of the reinforcement structure of the defective area of ​​the ground-connected wall constructed first in the present invention is that it also includes a concrete reinforcement layer formed by spraying on the inner wall of the foundation pit corresponding to the defective area.

[0013] The present invention also provides a construction method for reinforcing a defective area of ​​a first-constructed ground diaphragm wall, wherein the defective area is located on a side of the first-constructed ground diaphragm wall close to the later-constructed ground diaphragm wall, and the method comprises the following steps:

[0014] When constructing the post-construction ground diaphragm wall, make the end of the post-construction ground diaphragm wall close to the defective area;

[0015] A plurality of bored cast-in-place piles are driven along the setting direction of the post-construction ground connection wall on the side of the defective area away from the foundation pit, so that part of the bored cast-in-place piles are located at a part of the post-construction ground connection wall away from the foundation pit;

[0016] A plurality of MJS construction method piles are driven on the side of the defect area close to the foundation pit and the side away from the foundation pit, so that two adjacent MJS construction method piles are partially overlapped, thereby completing the construction of the reinforced structure.

[0017] A further improvement of the construction method of the present invention for first constructing the reinforcement structure of the defective area of ​​the ground-connected wall is that when constructing the MJS method piles, the MJS method piles located on the side of the defective area away from the foundation pit are arranged to partially overlap with the bored cast-in-place piles.

[0018] A further improvement of the construction method of the reinforcement structure of the defective area of ​​the ground-connected wall first constructed in the present invention is that it also includes: constructing a top beam on the top of the later-constructed ground-connected wall and then on the top of the first-constructed ground-connected wall, and locating the corresponding part of the top beam at the defective area.

[0019] A further improvement of the construction method of the present invention for first constructing the reinforcement structure of the defective area of ​​the ground-connected wall is that it also includes:

[0020] Provide support beams, and arrange the support beams at intervals along the height direction of the inner wall of the foundation pit. Extend one end of the support beam into the first constructed ground connection wall for anchoring, and extend the other end into the later constructed ground connection wall for anchoring.

[0021] A further improvement of the construction method of the present invention for first constructing the reinforcement structure of the defective area of ​​the ground-connected wall is that it also includes:

[0022] Fine stone concrete is sprayed on the corresponding defective areas on the inner wall of the foundation pit to form a concrete reinforcement layer.

[0023] The beneficial effects of the reinforcement structure of the defective area of ​​the ground-connected wall constructed first and the construction method thereof are as follows:

[0024] The present invention utilizes bored cast-in-place piles in combination with MJS method piles to reinforce defective areas, thereby avoiding the risks caused by removing defects in the defective areas, effectively solving the problem of support and water stopping, having good enclosure replacement effect, and facilitating on-site construction.

[0025] Support beams are used to connect and reinforce the successively constructed ground-anchored walls in the defective areas, thereby enhancing the overall stability of the successively constructed ground-anchored walls.

[0026] Sprayed anchor concrete is used to reinforce the soil in defective areas, and water reduction is carried out inside and outside the foundation pit to control the water pressure outside the pit and improve the safety factor of the foundation pit retaining wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a flow chart of a construction method of first constructing a reinforcement structure for a defective area of ​​a ground-connected wall.

[0028] Figure 2 This is a plan view of the reinforcement structure of the defective area of ​​the ground-connected wall constructed first in the present invention.

[0029] Figure 3 This is a cross-sectional view of the reinforcement structure of the defective area of ​​the ground-connected wall constructed first in the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0031] See also Figure 1 , the present invention provides a reinforcement structure for the defective area of ​​the first constructed ground-connected wall and a construction method thereof, which are used to solve the problem that the defects formed by the first constructed ground-connected wall make it impossible for the later constructed ground-connected wall to dock with it. If the defects are removed first, it may cause more quality and safety risks. The reinforcement structure and construction method of the present invention use bored cast-in-place piles combined with MJS method piles to reinforce the defective area, avoiding the risks caused by removing the protruding structure in the defective area, and effectively solving the problem of support and water stopping. The reinforcement structure for the defective area of ​​the first constructed ground-connected wall and its construction method of the present invention are described below in conjunction with the accompanying drawings.

[0032] See also Figure 2 , showing a plan view of the reinforcement structure of the defective area of ​​the ground-connected wall constructed in the present invention. Figure 3 , showing a cross-sectional view of the reinforcement structure of the defective area of ​​the ground-connected wall constructed in the present invention. Figure 2 and Figure 3 , the reinforcement structure of the defective area of ​​the ground-connected wall constructed first in the present invention is described.

[0033] like Figure 2 and Figure 3 As shown, the reinforcement structure of the defective area of ​​the first constructed ground dummy wall of the present invention is used to reinforce the defective area 12 of the first constructed ground dummy wall 11, and the defective area 12 is located on the side of the first constructed ground dummy wall 11 close to the later constructed ground dummy wall 13, the later constructed ground dummy wall 13 intersects with the setting direction of the first constructed ground dummy wall 11, and the end of the later constructed ground dummy wall 13 is set close to the defective area 12. The reinforcement structure of the present invention includes a plurality of bored cast-in-place piles 21 and a plurality of MJS method piles 22. The plurality of bored cast-in-place piles 21 are driven along the setting direction of the later constructed ground dummy wall 13 on the side of the defective area 12 away from the foundation pit, and some of the bored cast-in-place piles 21 are located on the side of the later constructed ground dummy wall 13 away from the foundation pit; the MJS method piles 22 are driven on the side of the defective area 12 close to the foundation pit and the side away from the foundation pit, and there is a partial overlap between two adjacent MJS method piles 22.

[0034] like Figure 2 and Figure 3 As shown, the two sections A4-2 and A4-3 of the first-construction ground diaphragm wall 11 are the side of the foundation pit close to the existing subway and other buildings. The later-construction ground diaphragm wall 13 intersects with the first-construction ground diaphragm wall 11. During the grooving process of the later-construction ground diaphragm wall 13, it was found that the side of the first-construction ground diaphragm wall 11 formed defects such as bulges and other protruding structures, collectively referred to as defective areas. The formation reason of the defective area 12 is unknown, but the existence of the defective area 12 has an impact on the normal construction of the later-construction ground diaphragm wall 13. If the traditional method of removing the defective area is adopted, it is easy to accidentally damage the first-construction ground diaphragm wall, thereby causing more quality and safety risks. The defective area with protruding structures such as bulges is likely to be caused by the leakage of concrete of the first-construction ground diaphragm wall. Therefore, the present invention chooses to construct bored cast-in-place piles and MJS method piles in the defective area instead of removing the defects, effectively solving the problem of support and water stopping.

[0035] Furthermore, the bored piles 21 are selected with corresponding pile diameters and quantities according to the length of the defective area 12. Part of the bored piles 21 are arranged on one side of the post-construction ground connection wall 13. Figure 2 In the example shown, three bored piles 21 are provided and arranged at intervals.

[0036] Preferably, the bored pile 21 has a pile diameter of 1m, an effective pile length of 39.2m, a pile spacing of 200mm, and the main reinforcement is 24 HRB400 steel bars with a diameter of 25mm. The spiral stirrups are HPB300 steel bars with a diameter of 10mm, with a spacing of 150, and reinforced steel bars with a diameter of 18mm are HRB400.

[0037] In a specific embodiment of the present invention, the MJS method pile 22 located at the defective area 12 away from the foundation pit side is partially overlapped with the bored cast-in-place pile 21 .

[0038] The defective area is reinforced internally and externally by using the MJS method piles 22 , and the partial overlap between adjacent MJS method piles 22 means that two MJS method piles 22 are interlocked.

[0039] When the construction defect area 12 is far away from the MJS construction method pile 22 on one side of the foundation pit, the MJS construction method pile is also engaged with the bored cast-in-place pile 21.

[0040] Preferably, the diameter of the MJS pile is 2.4 m, the depth is 23.5 m, and the cement content is 35%.

[0041] During the MJS pile construction process, dewatering wells are constructed inside and outside the foundation pit simultaneously, and then dewatering operations are organized. During the earth excavation process, the water level must be kept below 1m depth from the excavation surface.

[0042] In a specific embodiment of the present invention, Figure 3 As shown, a top pressure beam 14 is provided at the top of the later constructed ground diaphragm wall 13 and the top of the earlier constructed ground diaphragm wall 11 , and a corresponding portion of the top pressure beam 14 is located at the defective area 12 .

[0043] The bored cast-in-place piles, the MJS method piles, the first constructed ground connection wall 11 and the second constructed ground connection wall 13 are connected into a whole by means of the capping beam 14 .

[0044] In a specific embodiment of the present invention, Figure 3 As shown, it also includes a plurality of support beams 23 spaced apart along the height direction of the inner wall of the foundation pit, one end of the support beam 23 extends into the first constructed ground connecting wall 11 for anchoring, and the other end of the support beam 23 extends into the second constructed ground connecting wall 13 for anchoring.

[0045] The support beam 23 is preferably made of steel, such as 40# I-beam, and the length of the two ends of the support beam 23 anchored in the corresponding first-construction ground-connecting wall 11 and the later-construction ground-connecting wall 13 is 10 cm.

[0046] Furthermore, when the support beam 23 is provided, the support beam 23 is fixed to the corresponding steel bars in the ground connection wall by welding.

[0047] The support beam 23 is arranged to be staggered with the inner support and the surrounding purlin 33 used for supporting the foundation pit.

[0048] In a specific embodiment of the present invention, it also includes spraying a concrete reinforcement layer on the inner wall of the foundation pit corresponding to the defect area 12. Specifically, a 150mm thick C20 fine stone concrete is sprayed on the inner wall of the foundation pit, and the formed concrete reinforcement layer is used to prevent soil collapse.

[0049] The arrangement of the support beam 23 and the concrete reinforcement layer of the present invention is carried out step by step as the earthwork of the foundation pit is excavated. For example, after the earthwork of the foundation pit is excavated to a certain depth, a support beam 23 is arranged, and a concrete reinforcement layer is constructed in the corresponding inner wall area of ​​the foundation pit. After the foundation pit is excavated, a cushion layer 31 is constructed at the bottom of the foundation pit, and a bottom plate 32 is constructed on the cushion layer 31, and then the main building body in the foundation pit is constructed.

[0050] The present invention also provides a construction method for first constructing a reinforcement structure of a defective area of ​​a ground-connected wall, and the construction method is described below.

[0051] like Figure 1 As shown, in the construction method of the reinforcement structure of the defective area of ​​the first-constructed ground-connected wall of the present invention, the defective area is located on the side of the first-constructed ground-connected wall close to the later-constructed ground-connected wall, and the method comprises the following steps:

[0052] Combination Figure 2 and Figure 3 As shown, when the post-construction ground connecting wall 13 is constructed, the end of the post-construction ground connecting wall 13 is placed close to the defective area 12;

[0053] A plurality of bored cast-in-place piles 21 are driven along the setting direction of the post-construction ground connecting wall 13 on the side of the defective area 12 away from the foundation pit, so that part of the driven bored cast-in-place piles 21 is located at some of the post-construction ground connecting wall 13 away from the foundation pit;

[0054] A plurality of MJS construction method piles 22 are driven on the side of the defective area 12 close to the foundation pit and the side away from the foundation pit, so that two adjacent MJS construction method piles 22 are partially overlapped, thereby completing the construction of the reinforced structure.

[0055] During construction, construction preparations should be carried out first, including site preparation, technical preparation, material preparation, personnel preparation, and machinery preparation.

[0056] Site preparation: determine the construction scope and make site enclosure; connect the construction water pipeline, determine the transportation route of materials, equipment and earthwork; make temporary drainage of the construction site.

[0057] Technical preparation: Carefully read, study, and review construction drawings and construction specifications, participate in design briefings and drawing reviews; conduct on-site surveys to understand the terrain, hydrology, and construction environment.

[0058] Material preparation: Material preparation work must be ahead of project construction, meet the requirements of each construction stage of the project, and be timely and sufficient; prepare a material procurement and supply plan in advance, and the company must uniformly allocate and supply the circulating materials used in the project according to the plan. Samples of materials used in the project structure must be taken for testing, and only after passing the test can they be used in project construction.

[0059] Personnel preparation: Based on the technical characteristics of underground continuous wall construction, bored cast-in-place piles, and MJS method pile construction, we select experienced on-site management personnel and front-line operators.

[0060] Mechanical preparation: Special operation equipment for underground continuous wall construction, bored cast-in-place piles, and MJS method pile construction shall be inspected and debugged before entering the site to ensure that the equipment entering the site can be used normally. During the construction period, professional maintenance personnel shall be arranged to carry out maintenance and upkeep operations on site.

[0061] After construction preparation, measurements and layout are carried out on site to determine the locations of completed ground-anchored walls and the locations of ground-anchored walls to be constructed, and then determine the specific locations of defective areas.

[0062] Then, the construction of the post-construction ground-connected wall 13 is carried out, including the construction of the A4-32 and A4-33 sections. During the construction, the groove forming machine is used to construct A4-32 to the bulge area, the length of the area is measured, the ground-connected wall steel bars are processed, the ground-connected wall steel cage is hoisted by a truck crane, and then concrete is poured. Figure 2 The blue area of ​​A4-33 shown is a reinforced concrete ground-connected wall, and the red bulging area where A4-33 intersects with A4-2 and A4-3 on the north side is a mud-mixed plain concrete area.

[0063] After the construction of A4-33 is completed, 21 bored piles are added between A4-33 and A4-2 and A4-3. The pile diameter is 1m, the effective length of the pile body is 39.2m, the spacing between piles is 200mm, the main reinforcement is 24 HRB400 with a diameter of 25mm, the spiral stirrups are HPB300 with a diameter of 10mm, the spacing is 150, and the HRB400 with a diameter of 18mm is set. According to the size of the determined defective area, 3 bored piles are constructed.

[0064] To prevent leakage in the cast-in-place pile area, MJS was used to reinforce the inside and outside of the pit in the defective ground-connected wall area. The MJS method pile has a diameter of 2.4m, a depth of 23.5m, and a cement content of 35%.

[0065] When constructing MJS method piles, the MJS method piles located on the defective area away from the foundation pit side are arranged to partially overlap with the bored cast-in-place piles.

[0066] During the MJS method pile construction, dewatering wells inside and outside the foundation pit are constructed simultaneously, and then dewatering operations are organized. During the earth excavation process, the water level must be kept below 1m depth from the excavation surface.

[0067] Furthermore, the method further comprises: constructing a top beam at the top of the later constructed ground diaphragm wall and then at the top of the earlier constructed ground diaphragm wall, and positioning a corresponding portion of the top beam at the defective area.

[0068] When the earth excavation reaches the bottom elevation of the top beam, the earth excavation is stopped and the construction of the top beam begins. The ground-anchored wall and the bored concrete piles are connected into a whole by setting the top beam.

[0069] Furthermore, it also includes:

[0070] Provide support beams, set the support beams at intervals along the height direction of the inner wall of the foundation pit, extend one end of the support beam into the first constructed ground connection wall for anchoring, and extend the other end into the later constructed ground connection wall for anchoring.

[0071] In the middle of the upper and lower purlins, additional steel supports are installed. 40# I-beams are welded and reinforced with A4-33 and A4-2 main reinforcement bars, and both ends of the I-beams are extended into the ground-connected wall for 10cm anchoring.

[0072] Furthermore, the method further comprises: spraying fine stone concrete on the inner wall of the foundation pit corresponding to the defective area to form a concrete reinforcement layer.

[0073] For defective areas, first remove the loose soil on the surface layer, and then spray 150mm thick C20 fine stone concrete to prevent soil collapse.

[0074] The edge of the foundation pit of the present invention is about 15m away from the tunnel wall, the excavation depth of the foundation pit is 14.35m, the bottom of the foundation pit is about 15.3m above the subway tunnel, and the foundation pit retaining structure adopts a 1000mm thick underground continuous wall with a burial depth of 44.2m. The ground-connected wall near the subway side was built by other units in advance. During the trenching process of the ground-connected wall in the later construction, it was found that the ground-connected wall built in advance had a bulge 7m below the surface, and the bulge protruded about 1.5m into the foundation pit. Figure 2As shown, A4-2 and A4-3 are the ground-connected walls that have been built, and A4-32 and A4-33 are the ground-connected walls that have been constructed after entering the site. In view of the above-mentioned defective area problem of bulges, the traditional solution is to first remove the bulges, then construct the ground-connected walls, and add water-stopping measures at the junction of the new and old ground-connected walls. However, since it is impossible to clearly determine the cause of the bulges, the bulge problem cannot be ruled out as being caused by the leakage of concrete from the ground-connected walls that have been built. If traditional obstacle removal measures are taken, the ground-connected walls that have been built first will inevitably be "accidentally injured", causing more quality and safety risks. Therefore, the present invention uses bored cast-in-place piles combined with MJS method piles to reinforce defective ground-connected walls, avoiding the risks brought by removing bulges, effectively solving the problem of support and water-stopping, using I-beams to connect and reinforce the new and old ground-connected walls, and combining with the spraying and anchoring soil technology to enhance the overall stability of the connection between the new and old underground continuous walls. At the same time, a controlled dewatering well is added outside the foundation pit to control the water pressure outside the pit and improve the water safety factor outside the pit.

[0075] The present invention is described in detail above in conjunction with the embodiments of the accompanying drawings. A person skilled in the art can make various variations of the present invention according to the above description. Therefore, certain details in the embodiments should not constitute a limitation of the present invention, and the scope of protection of the present invention shall be defined by the scope of the attached claims.

Claims

1. A reinforcement structure for a defective area of ​​a first-constructed ground diaphragm wall, wherein the defective area is located on a side of the first-constructed ground diaphragm wall close to the second-constructed ground diaphragm wall, the second-constructed ground diaphragm wall intersects with the first-constructed ground diaphragm wall in its setting direction, and an end of the second-constructed ground diaphragm wall is arranged close to the defective area, characterized in that: The reinforcement structure comprises: A plurality of bored cast-in-place piles are driven along the setting direction of the post-construction ground connection wall on the side of the defective area away from the foundation pit, with some of the bored cast-in-place piles being located on the side of the post-construction ground connection wall away from the foundation pit; A plurality of MJS construction method piles are driven in the defective area on the side close to the foundation pit and the side far from the foundation pit, and two adjacent MJS construction method piles are partially overlapped.

2. The reinforcement structure of the defective area of ​​the pre-constructed ground-connected wall according to claim 1, characterized in that: The MJS construction method piles located on the side of the defective area far away from the foundation pit are partially overlapped with the bored cast-in-place piles.

3. The reinforcement structure of the defective area of ​​the pre-constructed ground-connected wall according to claim 1, characterized in that: A top beam is provided on the top of the later-constructed ground-connected wall and the top of the earlier-constructed ground-connected wall, and a corresponding portion of the top beam is located at the defective area.

4. The reinforcement structure of the defective area of ​​the pre-constructed ground-connected wall according to claim 1, characterized in that: It also includes a plurality of support beams spaced apart along the height direction of the inner wall of the foundation pit, one end of the support beam extends into the first-constructed ground-connected wall for anchoring, and the other end of the support beam extends into the later-constructed ground-connected wall for anchoring.

5. The reinforcement structure of the defective area of ​​the pre-constructed ground-connected wall according to claim 1, characterized in that: It also includes spraying a concrete reinforcement layer formed on the inner wall of the foundation pit corresponding to the defective area.

6. A construction method for reinforcing a defective area of ​​a first-constructed ground diaphragm wall, wherein the defective area is located on a side of the first-constructed ground diaphragm wall close to the later-constructed ground diaphragm wall, characterized in that: The method comprises the following steps: When constructing the post-construction ground diaphragm wall, make the end of the post-construction ground diaphragm wall close to the defective area; A plurality of bored cast-in-place piles are driven along the setting direction of the post-construction ground connection wall on the side of the defective area away from the foundation pit, so that part of the bored cast-in-place piles are located at a part of the post-construction ground connection wall away from the foundation pit; A plurality of MJS construction method piles are driven on the side of the defect area close to the foundation pit and the side away from the foundation pit, so that two adjacent MJS construction method piles are partially overlapped, thereby completing the construction of the reinforced structure.

7. The construction method of the reinforcement structure of the defective area of ​​the ground-connected wall first as claimed in claim 6 is characterized in that: When constructing the MJS method piles, the MJS method piles located on the defective area away from the foundation pit side are arranged to partially overlap with the bored cast-in-place piles.

8. The construction method of the reinforcement structure of the defective area of ​​the ground-connected wall first as claimed in claim 6 is characterized in that: Also includes: A top beam is constructed on the top of the later constructed ground diaphragm wall and then on the top of the earlier constructed ground diaphragm wall, and a corresponding portion of the top beam is located at the defective area.

9. The construction method of the reinforcement structure of the defective area of ​​the ground-connected wall first as claimed in claim 6, characterized in that: Also includes: Provide support beams, and arrange the support beams at intervals along the height direction of the inner wall of the foundation pit. Extend one end of the support beam into the first constructed ground connection wall for anchoring, and extend the other end into the later constructed ground connection wall for anchoring.

10. The construction method of the reinforcement structure of the defective area of ​​the ground-connected wall first as claimed in claim 6, characterized in that: Also includes: Fine stone concrete is sprayed on the corresponding defective areas on the inner wall of the foundation pit to form a concrete reinforcement layer.

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