A kind of abandoned shell recovery type underground continuous wall and construction method

Abstract

The present invention discloses a shell-recycling type underground continuous wall and a construction method. F-shaped plates and U-shaped plates are arranged at both ends of a front transverse plate and a rear transverse plate, with low processing difficulty. Adjacent steel components are connected by plugging and matching the F-shaped plates and the U-shaped plates. The structure is cleverly arranged, has good structural stability and is convenient to construct. Neither the F-shaped plate nor the U-shaped plate exceeds the outer side surface of the front transverse plate or the rear transverse plate, and will not affect the groove width and the concrete pouring thickness of the main structure. A drag reduction shell is sleeved on the outer surface of the steel component. After the strength of the main structure reaches the standard, the steel component can be removed by using a crane because the friction between the steel component and the drag reduction shell is small, so that the steel component can be reused, which solves the problem of difficult removal of the steel component and has strong economy and turnover. After the steel component is removed, fluidized solidified soil is used to grout and extrude the construction gap in the drag reduction shell, which improves the convenience of backfilling the construction gap and solves the technical problem of complex operation of filling the construction gap.

Description

Technical Field

[0001] The present invention relates to the technical field of underground continuous walls, and in particular to a discarded shell recovery type underground continuous wall and a construction method thereof. Background Art

[0002] With the continuous improvement of urbanization level, urban problems are becoming increasingly prominent, and the development and utilization of urban underground space has become one of the effective ways to solve the problems of big cities. At present, when excavating urban underground space foundation pits, in view of the fact that precipitation will cause ground settlement and endanger the safety of surrounding buildings (structures), in order to ensure water-free operation of the foundation pit, the deep foundation pit retaining structure often adopts cast-in-place reinforced concrete underground continuous wall, prefabricated underground continuous wall or steel underground continuous wall.

[0003] In order to overcome the problem that the existing cast-in-place reinforced concrete underground continuous wall, prefabricated underground continuous wall and steel underground continuous wall steel bars or steel components are put into use once and cannot be recycled, the existing Chinese invention patent with application number CN202311254332.8 discloses a prefabricated underground continuous wall construction method, which belongs to the field of foundation pit construction technology. The underground continuous wall includes a groove, a steel component arranged in the groove, a prefabricated concrete component arranged in the steel component, an inner film bag filled in the gap between the steel component and the prefabricated concrete component, an outer mold bag filled in the gap between the steel component and the stratum, and slurry filled in the inner film bag and the outer mold bag; adjacent steel components are spliced ​​to form a cavity for inserting the prefabricated concrete component; the inner film bag includes a bag body one, a resistance wire one evenly distributed on the bag body one, and a power line one connected to the resistance wire one; the outer mold bag includes a bag body two, a resistance wire two evenly distributed on the bag body two, and a power line two connected to the resistance wire two; the hardened slurry can be softened after being heated by the resistance wire one or the resistance wire two until it is liquefied. It can solve the problems of difficulty in removing prefabricated underground continuous wall steel components and failure to fill construction gaps in time.

[0004] The above scheme did not consider the difficulty of processing underground continuous wall steel components, the impact on the groove width and the thickness of the main structure casting, and the convenience of filling the construction gap during design. In actual operation, the following problems still exist:

[0005] First, the joint form of the steel component is an open steel pipe, which is relatively difficult to process compared to the special-shaped structure; secondly, the open steel pipe protrudes from the surface of the steel component, affecting the groove width and the thickness of the concrete pouring of the main structure; specifically, the open steel pipe protrudes from the surface of the steel component. In order to ensure the thickness of the protective layer of the steel bars of the main structure at the protruding position of the open steel pipe, it is necessary to increase the thickness of the protective layer of the steel bars of the main structure outside the protruding position of the open steel pipe, which also increases the contact area between the steel component and the main structure, increases the friction resistance, and thus increases the pull-out force and the difficulty of pulling out the steel component;

[0006] Second, filling the inner and outer film bags with sulfur mortar and injecting sulfur mortar into the film bags has a complex structure and process, poor operability, and low construction efficiency;

[0007] Third, although filling the cavities between adjacent steel components with precast concrete blocks reduces a lot of wet work, it will still cause gaps between the precast concrete blocks and the steel components. When using membrane bags, multiple backfilling is still required, affecting the overall construction quality of the underground continuous wall. Summary of the invention

[0008] The present invention provides a shell recovery type underground continuous wall and a construction method, which are used to solve the technical problems in the prior art, such as the protrusions at the connection points of steel components leading to great processing difficulty and increased thickness of the protective layer of the steel bars of the main structure, increased contact area between the steel components and the main structure, and thus increased difficulty in removing the steel components; and the use of sulfur mortar has complex procedures and poor operability leading to low construction efficiency.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention provides a shell recovery type underground continuous wall, comprising a trench and a retaining structure, wherein the retaining structure comprises a plurality of retaining units arranged in the trench, and the plurality of retaining units are connected and arranged along the length direction of the trench; a set of retaining units comprises two mutually connected steel components, a drag reduction shell, a water-stopping bag and cast-in-place concrete;

[0011] The steel component is an I-shaped plate as a whole, including a front transverse plate, a rear transverse plate and a vertical plate connected between the front transverse plate and the rear transverse plate; the drag reduction shell is a shell structure, which has the same shape as the steel component and is sleeved on the surface of the steel component as the outer shell of the steel component;

[0012] A first F-shaped plate is arranged at the left end of the front horizontal plate, and a first U-shaped plate is arranged at the right end; a second U-shaped plate is arranged at the left end of the rear horizontal plate, and a second F-shaped plate is arranged at the right end; wherein the first F-shaped plate and the second F-shaped plate are centrally symmetrical with the center point of the vertical plate as the symmetrical point, and the first U-shaped plate and the second U-shaped plate are also centrally symmetrical with the center point of the vertical plate as the symmetrical point;

[0013] In the two interconnected steel components, the first U-shaped plate of the left steel component and the first F-shaped plate of the right steel component are clamped and fixed, and the second F-shaped plate of the left steel component and the second U-shaped plate of the right steel component are clamped and fixed; water-stop bags are arranged at the joints between the left steel component and the right steel component; and the closed space enclosed by the left steel component and the right steel frame is filled with cast-in-place concrete.

[0014] Preferably, the first F-type plate is a strip plate, which is arranged in the height direction of the left end of the front cross plate; the first F-type plate includes a main board, and a convex rib is respectively arranged on the outer edge and the middle of the inner side surface of the main board, so that the cross section of the first F-type plate is "F"-shaped; the inner edge of the main board of the first F-type plate is fixedly connected to the left end of the front cross plate, so that the back of the main board is flush with the inner side surface of the front cross plate.

[0015] Preferably, the first U-shaped plate is arranged in the height direction of the right end of the front transverse plate; the first U-shaped plate includes a bottom plate, a long side plate and a short side plate; the opening of the first U-shaped plate faces the front transverse plate, and the side of the long side plate away from the bottom plate is fixedly connected to the inner side surface of the edge of the front transverse plate; the bottom plate is parallel to the front transverse plate, and the end of the bottom plate away from the long side plate exceeds the edge of the front transverse plate; the width of the short side plate is smaller than the long side plate, one side of the short side plate is fixedly connected to the bottom plate, and the other side has a spacing with the front transverse plate; the semi-enclosed space enclosed by the first U-shaped plate and the front transverse plate is used to cooperate with the first F-shaped plate of the adjacent steel structure for insertion and clamping.

[0016] Preferably, the water-stop bag is a hollow bag belt, which is arranged between the convex ribs of the first F-shaped plate and the second F-shaped plate for waterproofing.

[0017] Preferably, there are strata on both sides of the groove, and filling material is arranged between the steel component and the strata.

[0018] Preferably, the filling material is fluidized solidified soil or quick-setting slurry.

[0019] Preferably, the top surface of the steel component is higher than the top surface of the drag reduction shell, and the top surface of the steel component is provided with lifting holes or lifting rings for early stage lifting and later removal.

[0020] Preferably, the drag reduction shell is made of plastic material, and a drag reduction layer is provided between the drag reduction shell and the steel component to reduce the friction between the steel component and the drag reduction shell.

[0021] Preferably, the drag reduction layer is made of powder or oil with a low friction coefficient such as polytetrafluoroethylene and molybdenum disulfide.

[0022] The present invention also provides a construction method for the above-mentioned abandoned shell recovery type underground continuous wall, comprising the following steps:

[0023] Step 1: Measure and lay out at the construction site to determine the specific location of the enclosure structure;

[0024] Step 2: Dig the guide wall trench and construct the steel guide wall;

[0025] Step 3: According to the construction drawing design, under the condition of mud wall protection, trenching equipment is used to excavate the retaining structure trench and clean the bottom;

[0026] Step 4: Install the drag reduction shell on the steel structure, install the water-stop bag on the first F-type plate and the second F-type plate, hang the steel structure, drag reduction shell and water-stop bag into the groove, fill the water-stop bag with water and pressurize it, and at the same time, discharge the mud inside the groove of the enclosure structure;

[0027] Step 5: Connect and fix the steel structure to the steel guide wall;

[0028] Step 6: Pour concrete into the cavity formed by adjacent steel components and drain part of the slurry from the trench of the retaining structure;

[0029] Step 7: Repeat steps 4 to 6 to complete the construction of the steel components and concrete parts of the first enclosure unit;

[0030] Step 8: Inject filler into the gap between the steel structure and the stratum to complete the construction of the first enclosure unit;

[0031] Step 9: Repeat steps 1 to 8 until all construction contents of the second enclosure unit are completed;

[0032] Step 10: Repeat step 9 until the construction of the retaining structure of the entire foundation pit is completed;

[0033] Step 11: After the main structure is completed and the strength reaches the designed strength, remove the steel components from the drag reduction shell;

[0034] Step 12: While the steel components are being pulled out, filler is injected into the pull-out position, i.e., inside the drag reduction shell, in real time to squeeze and fill the construction gap after the steel components are pulled out, thereby completing the backfill construction of the underground continuous wall construction gap.

[0035] The beneficial effects of the present invention are embodied in:

[0036] 1) The present invention provides a shell recovery type underground continuous wall and a construction method. F-shaped plates and U-shaped plates are arranged at both ends of the front horizontal plate and the rear horizontal plate, which are easy to process. Adjacent steel members are connected by plugging and matching between the F-shaped plates and the U-shaped plates. The structure is cleverly arranged, has good integrity, good structural stability and is convenient to construct. The F-shaped plates and the U-shaped plates do not extend beyond the outer side of the front horizontal plate or the rear horizontal plate, and will not affect the groove width and the concrete pouring thickness of the main structure.

[0037] 2) The present invention provides a shell-recycling underground continuous wall and construction method. The outer surface of the steel component is covered with a drag-reducing shell, which plays a role similar to a mold. After the strength of the main structure reaches the standard, the friction between the steel component and the drag-reducing shell is small, and the steel component can be removed by a crane, so that the steel component can be reused, which solves the problem of difficult removal of the steel component and has strong economy and turnover.

[0038] 3) The present invention provides a shell-recovery type underground continuous wall and construction method. After the steel components are removed, fluidized solidified soil is used to grout and squeeze into the drag reduction shell to fill the construction gap, thereby improving the convenience of backfilling the construction gap and solving the technical problem of complex operation of filling the construction gap.

[0039] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing the present invention; the main purpose and other advantages of the present invention may be realized and obtained through the solutions particularly pointed out in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a plan view of the enclosure structure of the present invention in the trench.

[0041] Figure 2 It is a plan view of the steel member of the present invention.

[0042] Figure 3 It is a plan view of the drag reducing shell of the present invention.

[0043] Figure 4 It is a plan view of the enclosure structure of the present invention after the steel components are removed.

[0044] Reference numerals: 1-groove, 2-enclosing unit, 21-steel member, 211-front transverse plate, 212-rear transverse plate, 213-vertical plate, 214-first F-type plate, 2141-main plate, 2142-convex rib,

[0045] 215-first U-shaped plate, 2151-bottom plate, 2152-long side plate, 2153-short side plate,

[0046] 216- second F-type plate, 217- second U-type plate,

[0047] 22-drag reduction shell, 23-water-stop bag, 24-cast-in-place concrete, 3-stratum, 4-filling material. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is described in detail below through examples. The following examples are merely exemplary and can only be used to explain and illustrate the technical solution of the present invention, but cannot be interpreted as limiting the technical solution of the present invention.

[0049] This embodiment takes the foundation pit construction plan of a certain construction project as an example. Since in the prior art, the connection of the steel member 21 is an open steel pipe, which leads to problems such as great difficulty in processing and increased thickness of the concrete protective layer, the design is optimized on this basis, and the U-shaped plate and the F-shaped plate are alternately arranged at both ends and each side of the steel member 21, ensuring that the F-shaped plate is close to the steel member 21, and the structure is cleverly arranged, has good integrity, and good structural stability; in the prior art, the sulfur mortar is heated to soften it, thereby reducing the squeezing force and friction between the precast concrete member and the steel member 21, so that the steel member 21 is easy to remove. However, due to its poor operability, it is not practical in actual construction. Therefore, this embodiment abandons this solution, and realizes the later removal of the steel component 21 by arranging a drag reduction shell 22 on the surface of the steel component 21, which greatly reduces the difficulty of removing the steel component 21, improves the construction efficiency and recovery rate of the steel component 21 removal, and at the same time, after the steel component 21 is removed, grouting and extrusion on both sides are used to fill the construction gap, which improves the convenience of backfilling the construction gap and has strong practicality and operability. In actual engineering applications, this embodiment solves the problems of the existing steel component 21 being difficult to process and affecting the width of the trench 1 and the thickness of the concrete pouring of the main structure. The structure is reasonably set up, which reduces the engineering cost and has strong economy and application prospects.

[0050] Reference Figure 1 The present invention provides a shell recovery type underground continuous wall, comprising a trench 1 and a retaining structure, wherein the retaining structure comprises a plurality of retaining units 2 arranged in the trench 1, wherein the plurality of retaining units 2 are connected and arranged along the length direction of the trench 1; a group of retaining units 2 comprises two mutually connected steel components 21, a drag reduction shell 22, a water-stopping bag 23 and cast-in-place concrete 24; both sides of the trench 1 are strata 3, and a filling material 4 is arranged between the steel component 21 and the stratum 3, and the filling material 4 is made of fluidized solidified soil or quick-setting slurry.

[0051] Reference Figure 2 and Figure 3 The steel component 21 is an I-shaped plate as a whole, including a front transverse plate 211, a rear transverse plate 212 and a vertical plate 213 connected between the front transverse plate 211 and the rear transverse plate 212; the drag reduction shell 22 is a shell structure, which is the same shape as the steel component 21, and is sleeved on the surface of the steel component 21 as the outer shell of the steel component 21; the drag reduction shell 22 is made of plastic material, and a drag reduction layer is arranged between the drag reduction shell 22 and the steel component 21, which is used to reduce the friction between the steel component 21 and the drag reduction shell 22, and the drag reduction layer adopts powders or oils with low friction coefficients such as polytetrafluoroethylene and molybdenum disulfide; the top surface of the steel component 21 is higher than the top surface of the drag reduction shell 22, and the top surface of the steel component 21 is provided with hanging holes or hanging rings for early hoisting and easy removal in the later stage.

[0052] A first F-shaped plate 214 is disposed at the left end of the front transverse plate 211, and a first U-shaped plate 215 is disposed at the right end. A second U-shaped plate 217 is disposed at the left end of the rear transverse plate 212, and a second F-shaped plate 216 is disposed at the right end. The first F-shaped plate 214 and the second F-shaped plate 216 are symmetrical with respect to the center point of the vertical plate 213, and the first U-shaped plate 215 and the second U-shaped plate 217 are also symmetrical with respect to the center point of the vertical plate 213. The first F-shaped plate 214 It is a strip plate, which is arranged in the height direction of the left end of the front cross plate 211; the first F-type plate 214 includes a main board 2141, and a convex rib 2142 is respectively provided on the outer edge and the middle of the inner side of the main board 2141, so that the cross section of the first F-type plate 214 is "F"-shaped; the inner edge of the main board 2141 of the first F-type plate 214 is fixedly connected to the left end of the front cross plate 211, so that the back of the main board 2141 is flush with the inner side of the front cross plate 211. The first U-shaped plate 215 is arranged in the height direction of the right end of the front transverse plate 211; the first U-shaped plate 215 includes a bottom plate 2151, a long side plate 2152 and a short side plate 2153; the opening of the first U-shaped plate 215 faces the front transverse plate 211, and the side of the long side plate 2152 away from the bottom plate 2151 is fixedly connected to the inner side surface of the edge of the front transverse plate 211; the bottom plate 2151 is parallel to the front transverse plate 211, and the end of the bottom plate 2151 away from the long side plate 2152 exceeds the edge of the front transverse plate 211; the width of the short side plate 2153 is smaller than the long side plate 2152, one side of the short side plate 2153 is fixedly connected to the bottom plate 2151, and the other side has a spacing with the front transverse plate 211; the semi-enclosed space enclosed by the first U-shaped plate 215 and the front transverse plate 211 is used to cooperate with the first F-shaped plate 214 of the adjacent steel member 21 for insertion and clamping.

[0053] In the two interconnected steel components 21, the first U-shaped plate 215 of the left steel component 21 and the first F-shaped plate 214 of the right steel component 21 are clamped and fixed, and the second F-shaped plate 216 of the left steel component 21 and the second U-shaped plate 217 of the right steel component 21 are clamped and fixed; a water-stop bag 23 is provided at the joint between the left steel component 21 and the right steel component 21, and the water-stop bag 23 is a hollow bag belt, which is provided between the convex ribs 2142 of the first F-shaped plate 214 and the second F-shaped plate 216 for waterproofing; the closed space enclosed by the left steel component 21 and the right steel frame is filled with cast-in-place concrete 24.

[0054] The present invention also provides a construction method for the above-mentioned abandoned shell recovery type underground continuous wall, comprising the following steps:

[0055] Step 1: Measure and lay out at the construction site to determine the specific location of the enclosure structure;

[0056] Step 2: excavating a guide wall trench 1 and constructing a steel guide wall;

[0057] Step 3: According to the construction drawing design, under the condition of mud wall protection, trenching equipment is used to excavate the retaining structure trench 1 and clean the bottom;

[0058] Step 4: Install the drag reduction shell 22 on the steel member 21, install the water-stopping bag 23 on the first F-shaped plate 214 and the second F-shaped plate 216, hang the steel member 21, the drag reduction shell 22 and the water-stopping bag 23 into the groove 1, fill the water-stopping bag 23 with water and pressurize it, and at the same time, discharge the mud inside the groove 1 of the enclosure structure;

[0059] Step 5: Connect and fix the steel member 21 to the steel guide wall;

[0060] Step 6: pouring concrete in the cavity formed by the adjacent steel members 21, and at the same time draining part of the slurry in the retaining structure groove 1;

[0061] Step 7: Repeat steps 4 to 6 to complete the construction of the steel member 21 and concrete part of the first enclosure unit 2;

[0062] Step 8: injecting filler 4 into the gap between the steel member 21 and the stratum 3 to complete the entire construction of the first enclosure unit 2;

[0063] Step 9: Repeat steps 1 to 8 until all construction contents of the second enclosure unit 2 are completed;

[0064] Step 10: Repeat step 9 until the construction of the retaining structure of the entire foundation pit is completed;

[0065] Step 11: After the main structure is completed and its strength reaches the designed strength, the steel member 21 is removed from the drag reduction shell 22;

[0066] Step 12: Reference Figure 4 When the steel member 21 is removed, the filling material 4 is injected into the removal position, that is, inside the drag reduction shell 22 in real time to squeeze and fill the construction gap after the steel member 21 is removed, thereby completing the backfill construction of the underground continuous wall construction gap.

[0067] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that a technician familiar with the technical field can think of within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A shell recovery type underground continuous wall, characterized in that: The invention comprises a groove (1) and a protective structure, wherein the protective structure comprises a plurality of groups of protective units (2) arranged in the groove (1), and the plurality of groups of protective units (2) are connected and arranged along the length direction of the groove (1); a group of protective units (2) comprises two mutually connected steel components (21), a drag reduction shell (22), a water-stopping bag (23) and cast-in-place concrete (24); The steel member (21) is an I-shaped plate as a whole, comprising a front transverse plate (211), a rear transverse plate (212), and a vertical plate (213) connected between the front transverse plate (211) and the rear transverse plate (212); the drag reduction shell (22) is a shell structure having the same shape as the steel member (21), and is sleeved on the surface of the steel member (21) as an outer shell of the steel member (21); A first F-shaped plate (214) is arranged at the left end of the front transverse plate (211), and a first U-shaped plate (215) is arranged at the right end; a second U-shaped plate (217) is arranged at the left end of the rear transverse plate (212), and a second F-shaped plate (216) is arranged at the right end; wherein the first F-shaped plate (214) and the second F-shaped plate (216) are centrally symmetrical with the center point of the vertical plate (213) as the symmetrical point, and the first U-shaped plate (215) and the second U-shaped plate (217) are also centrally symmetrical with the center point of the vertical plate (213) as the symmetrical point; In two interconnected steel members (21), a first U-shaped plate (215) of the left steel member (21) and a first F-shaped plate (214) of the right steel member (21) are clamped and fixed, and a second F-shaped plate (216) of the left steel member (21) and a second U-shaped plate (217) of the right steel member (21) are clamped and fixed; a water-stop bag (23) is provided at the joint between the left steel member (21) and the right steel member (21); and a closed space enclosed by the left steel member (21) and the right steel frame is filled with cast-in-place concrete (24).

2. The shell recovery type underground continuous wall according to claim 1, characterized in that: The first F-shaped plate (214) is a strip plate and is arranged in the height direction of the left end of the front transverse plate (211); the first F-shaped plate (214) comprises a main plate (2141), and a convex rib (2142) is respectively arranged on the outer edge and the middle of the inner side surface of the main plate (2141), so that the cross section of the first F-shaped plate (214) is in an "F" shape; the inner edge of the main plate (2141) of the first F-shaped plate (214) is fixedly connected to the left end of the front transverse plate (211), so that the back side of the main plate (2141) is flush with the inner side surface of the front transverse plate (211).

3. The shell recovery type underground continuous wall as claimed in claim 2, characterized in that: The first U-shaped plate (215) is arranged along the right end of the front transverse plate (211) in the height direction; the first U-shaped plate (215) comprises a bottom plate (2151), a long side plate (2152) and a short side plate (2153); the opening of the first U-shaped plate (215) faces the front transverse plate (211); a side of the long side plate (2152) away from the bottom plate (2151) is fixedly connected to the inner side surface of the edge of the front transverse plate (211); the bottom plate (2151) is parallel to the front transverse plate (211); One end of the short side plate (2151) away from the long side plate (2152) exceeds the edge of the front transverse plate (211); the width of the short side plate (2153) is smaller than that of the long side plate (2152); one side of the short side plate (2153) is fixedly connected to the bottom plate (2151), and the other side is spaced apart from the front transverse plate (211); the semi-enclosed space enclosed by the first U-shaped plate (215) and the front transverse plate (211) is used to cooperate with the first F-shaped plate (214) of the adjacent steel member (21) for insertion and clamping.

4. The shell recovery type underground continuous wall as claimed in claim 2, characterized in that: The water-stopping bag (23) is a hollow bag belt, which is arranged between the convex ribs (2142) of the first F-shaped plate (214) and the second F-shaped plate (216) and is used for waterproofing.

5. The shell recovery type underground continuous wall according to claim 1, characterized in that: There are strata (3) on both sides of the groove (1), and a filling material (4) is provided between the steel component (21) and the strata (3).

6. The shell recovery type underground continuous wall as claimed in claim 5, characterized in that: The filling material (4) is fluidized solidified soil or quick-setting slurry.

7. The shell recovery type underground continuous wall as claimed in claim 4, characterized in that: The top surface of the steel component (21) is higher than the top surface of the drag reduction shell (22), and the top surface of the steel component (21) is provided with a lifting hole or a lifting ring for early stage lifting and later removal.

8. The shell recovery type underground continuous wall according to claim 1, characterized in that: The drag reduction shell (22) is made of plastic material, and a drag reduction layer is provided between the drag reduction shell (22) and the steel component (21) to reduce the friction between the steel component (21) and the drag reduction shell (22).

9. The shell recovery type underground continuous wall according to claim 8, characterized in that: The drag reduction layer is made of polytetrafluoroethylene or molybdenum disulfide.

10. A method for constructing a shell recovery underground continuous wall according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: Measure and lay out at the construction site to determine the specific location of the enclosure structure; Step 2: excavating a guide wall trench (1) and constructing a steel guide wall; Step 3: According to the construction drawing design, under the condition of mud wall protection, use trenching equipment to excavate the retaining structure trench (1) and clean the bottom; Step 4: Install the drag reduction shell (22) on the steel component (21), install the water-stopping bag (23) on the first F-shaped plate (214) and the second F-shaped plate (216), hang the steel component (21), the drag reduction shell (22) and the water-stopping bag (23) into the groove (1), fill the water-stopping bag (23) with water and pressurize it, and at the same time, discharge the mud inside the groove (1) of the enclosure structure; Step 5: Connect and fix the steel member (21) to the steel guide wall; Step 6: pouring concrete into the cavity formed by the adjacent steel members (21), while draining part of the slurry in the retaining structure groove (1); Step 7: Repeat steps 4 to 6 to complete the construction of the steel component (21) and concrete part of the first enclosure unit (2); Step 8: injecting filler (4) into the gap between the steel component (21) and the stratum (3), completing the entire construction content of the first enclosure unit (2); Step 9: Repeat steps 1 to 8 until all construction contents of the second enclosure unit (2) are completed; Step 10: Repeat step 9 until the construction of the retaining structure of the entire foundation pit is completed; Step 11: After the main structure is completed and its strength reaches the designed strength, the steel component (21) is removed from the drag reduction shell (22); Step 12: While the steel member (21) is being removed, the filling material (4) is injected into the removal position, i.e., the interior of the drag reduction shell (22), in real time to squeeze and fill the construction gap after the steel member (21) is removed, thereby completing the backfill construction of the underground continuous wall construction gap.

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