Deep foundation pit elevator shaft and sump nest support forming construction process

Abstract

This invention relates to the field of deep foundation pit support construction technology, specifically a nested support construction process for deep foundation pit elevator shafts and sump pits. It solves the problem that traditional caisson waterproofing technology is prone to failure due to pit wall collapse in highly permeable gravel strata, making it difficult to create stable construction conditions. The process includes a steel caisson support structure, within which a steel caisson waterproofing structure is nested. This steel caisson waterproofing structure is used in conjunction with the steel caisson support structure for nested construction. This invention, through the nested cooperation of the steel caisson support structure and the steel caisson waterproofing structure, and the injection of a self-compacting concrete filling layer, achieves an integrated support and waterproofing effect during construction. It creates a stable, dry, and enclosed working space in easily collapsible, highly permeable strata, solving the problem of failure of traditional single waterproofing technology and creating safe and reliable conditions for subsequent structural construction.

Description

Technical Field

[0001] This invention relates to the field of deep foundation pit support construction technology, specifically a nested support construction process for deep foundation pit elevator shafts and sump pits. Background Technology

[0002] With the development of urban construction, the development and utilization of underground space has become more extensive, and the number of deep foundation pit projects has increased. In special strata (such as sand and gravel strata and high groundwater level conditions), it is difficult to dewater local deep water collection pits (elevator shafts, water collection pits). Measures such as increasing drainage wells and open ditches have no significant dewatering effect, resulting in the stagnation of the subbase construction at the location of elevator shafts and water collection pits, and the inability to carry out large-scale foundation construction.

[0003] Existing caisson waterproofing technology is prone to failure due to pit wall collapse in high-permeability sand and gravel strata, making it difficult to create stable construction conditions; therefore, it does not meet the current requirements. In response, we propose a construction process for nested support between deep foundation pit elevator shaft and sump pit. Summary of the Invention

[0004] The purpose of this invention is to provide a construction process for nested support molding of deep foundation pit elevator shafts and sump pits, in order to solve the problems mentioned in the background art, such as the failure of caisson water-proof technology due to pit wall collapse in sand and gravel high-permeability strata, and the difficulty in constructing stable construction conditions.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a construction process for nested support molding of elevator shafts and sump pits in deep foundation pits, comprising a steel caisson support structure, wherein a steel caisson waterproof structure is nested inside the steel caisson support structure, the steel caisson waterproof structure is used to cooperate with the steel caisson support structure in nested construction, a self-compacting concrete filling layer is filled between the steel caisson support structure and the steel caisson structure, and an anti-buoyancy concrete layer is poured on the outside of the steel caisson support structure.

[0006] Preferably, the steel caisson support structure includes a steel caisson body, connecting steel pipes, steel caisson lifting rings, and anti-buoyancy anchors. The steel caisson body is constructed by welding channel steel keel and steel plate. Multiple connecting steel pipes are welded to the inner side of the steel caisson body. Multiple steel caisson lifting rings are fixedly installed on the top of the steel caisson body. Multiple anti-buoyancy anchors are welded to the outer side of the steel caisson body. All anti-buoyancy anchors penetrate into the interior of the anti-buoyancy concrete layer.

[0007] Preferably, the steel caisson water-proof structure includes a steel caisson body, keel supports, pressure relief holes, plugs, and steel caisson lifting rings. The steel caisson body is constructed by welding channel steel keels and steel plates. Multiple keel supports are provided on the inner surface of the steel caisson body. A pressure relief hole is opened in the middle of the bottom plate of the steel caisson body. A plug is movably installed on the surface of the pressure relief hole. Multiple steel caisson lifting rings are fixedly connected between the outer side of the steel caisson body and the steel caisson body.

[0008] Preferably, the construction device further includes an independent anti-buoyancy steel caisson structure, which is used for non-nested construction; The independent anti-buoyancy steel caisson structure includes an independent caisson body, keel, connecting support components, and steel mesh. The independent caisson body is welded from channel steel keel and steel plate. Multiple connecting support components are fixedly installed outward from the bottom of the independent caisson body. The surface of each connecting support component is provided with steel mesh. Multiple keels are welded to the bottom of the independent caisson body and the surface of the connecting support components.

[0009] Preferably, the construction device further includes a buried water pump structure installed at the bottom of the pit for pumping out the water accumulated at the bottom of the steel caisson waterproof structure, and the output end of the buried water pump structure is equipped with a water pump pipe.

[0010] A construction process for a nested support molding construction device for deep foundation pit elevator shafts and sump pits includes the following steps: S1: First, investigate the geological and hydrological conditions of the construction area and formulate a specific construction plan; S2: Depending on the actual situation, choose one of the following for construction and installation: a nested support structure combining steel caisson support structure and steel caisson waterproofing structure, or a non-nested support structure consisting of an independent anti-buoyancy steel caisson structure. When there is a risk of pit wall collapse, a nested support mode combining steel caisson support structure and steel caisson waterproofing structure is implemented: the steel caisson support structure is fabricated and hoisted into the pre-set pit, and the soil is excavated in layers to sink it to the design elevation; then, anti-buoyancy anchors are welded to the outside of the steel caisson and an anti-buoyancy concrete layer is poured; after the counterweight concrete has set, the steel caisson waterproofing structure is hoisted into the inside of the steel caisson support structure and precisely positioned, and the two are welded and fixed by steel caisson lifting rings; self-compacting concrete is poured into the gap between the two to form a self-compacting concrete filling layer. When the risk of pit wall collapse is low, the independent anti-buoyancy steel caisson structure is used as the sole non-nested support mode: the independent anti-buoyancy steel caisson structure is processed, and a foundation pit slightly larger than its counterweight area is dug at the installation position. The independent anti-buoyancy steel caisson structure is lowered into place and fixed by water injection or additional counterweight. Counterweight concrete is poured in the area enclosed by the connecting support components at its bottom and around it for stabilization. S3: Utilize the pressure relief holes of the steel caisson water-proof structure or the internal space of the independent anti-buoyancy steel caisson structure, combined with the buried water pump structure to pump out accumulated water and create a dry working environment. S4: Drain the water inside the box, carry out waterproofing layer construction, steel bar binding and concrete pouring, and complete the formation of the water sump or elevator shaft structure. S5: Select different methods for waterproofing the penetration joints based on the actual situation: For dewatering steel pipe wells: Install a water-stop sleeve with a water-stop steel plate and flange cover at the position where the well pipe penetrates the bottom plate, and construct an advanced water-stop bottom plate around the sleeve; construct two layers of waterproofing to ensure that the waterproofing layer ends are sealed on the water-stop steel plate; after dewatering stops, fill the well and seal the flange cover. For the support grid column: weld additional steel gusset plates and ring-shaped waterstop steel plates at the predetermined elevation of the column body; set up a post-cast zone around the column and set up waterstop steel plates at the construction joint; when the structure is constructed in the later stage, cut off the grid column to the design elevation, weld the end plate and complete the waterproof layer sealing, and then pour the post-cast zone concrete. S6: Well sealing construction: For dewatering wells that need to be abandoned, chemical grouting is used for sealing. Cement-water glass grout is injected into the formation around the well pipe through the drill pipe to form an overlapping consolidation and water-stopping area.

[0011] Preferably, in step S, after the independent anti-buoyancy steel caisson structure sinks, a keel support can be installed inside the independent caisson body to reinforce the independent caisson body. At the same time, a pressure relief hole can be opened in the middle of the bottom plate of the independent caisson body, and the pressure relief hole can be sealed with a plug to facilitate drainage through the pressure relief hole.

[0012] Preferably, after the steel caisson waterproof structure or independent anti-buoyancy steel caisson structure is installed and the anti-buoyancy measures and counterweights meet the requirements, the water inside the independent anti-buoyancy steel caisson structure is drained first, and the installed keel support, plugs and other support structures are removed. Then, the inside and outside corners of the caisson are rounded with cement mortar before waterproofing and bottom plate structure construction are carried out to further ensure the anti-buoyancy capability of the nested support structure.

[0013] Preferably, after the internal waterproofing construction of the steel caisson waterproofing structure or the independent anti-buoyancy steel caisson structure is completed, the reinforcement binding of the sump pit and elevator shaft structure and the concrete pouring are carried out. First, a raft structure formed by the upper and lower raft plates is installed on the outside of the top of the steel caisson waterproofing structure or the independent anti-buoyancy steel caisson structure, and haunch reinforcement is installed between the upper and lower raft plates. Then, waterstop steel plates and rubber waterstop strips are inserted into the surface of the steel caisson waterproofing structure or the independent anti-buoyancy steel caisson structure to set up construction joints.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention integrates the support structure of the steel caisson with the waterproof structure of the steel caisson, and fills the gap with self-compacting concrete. This allows the device to achieve the effect of integrated support and waterproofing during construction, creating a stable, dry, and enclosed working space in easily collapsible and highly permeable strata. This solves the problem of failure of traditional single waterproofing technology and creates safe and reliable conditions for subsequent structural construction. 2. This invention, by setting pressure relief holes and working in conjunction with the buried water pump system, and by using an anti-buoyancy counterweight concrete layer to provide external pressure, enables the process to achieve a graded anti-buoyancy effect that combines active pressure relief and passive counterweight during construction. This effectively resists the buoyancy of groundwater, ensures the structural stability of the steel caisson during installation and concrete pouring, and prevents it from floating or deforming. 3. This invention provides a nested installation of steel caisson support structure and steel caisson waterproof structure, or selects an independent anti-buoyancy steel caisson structure as a solution. This allows the construction process to flexibly select the construction mode according to the actual geological conditions. Under conditions with good soil quality and low risk, it simplifies the structure, saves materials and construction time, and improves the economy and engineering adaptability of the process. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the main construction operations of the present invention; Figure 2 This is a schematic diagram of the nested structure of the steel caisson support structure and the steel caisson water-proof structure of the present invention; Figure 3 This is a schematic diagram of the steel caisson structure of the present invention; Figure 4 This is a schematic diagram of the counterweight for the installation and backfilling of the non-nested caisson of the present invention; Figure 5 This is a schematic diagram of the installation of the template for the non-nested caisson of the present invention; Figure 6 This is a construction diagram of the internal structure of the non-nested caisson of the present invention.

[0016] In the diagram: 1. Steel caisson support structure; 101. Steel caisson main body; 102. Connecting steel pipe; 103. Steel caisson lifting ring; 104. Anti-buoyancy anchor; 2. Steel caisson water-proof structure; 201. Steel caisson main body; 202. Keel support; 203. Pressure relief hole; 204. Plug; 205. Steel caisson lifting ring; 3. Self-compacting concrete filling layer; 4. Anti-buoyancy concrete layer; 5. Buried water pump structure; 6. Independent anti-buoyancy steel caisson structure; 601. Independent caisson main body; 602. Keel; 603. Connecting support component; 604. Steel mesh; 7. Water pump pipe; 8. Haunch reinforcement; 9. Raft slab upper plate; 10. Raft slab lower plate; 11. Construction joint; 12. Waterstop steel plate; 13. Rubber waterstop strip. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Please see Figures 1 to 6 The present invention provides an embodiment of a construction process for nested support molding of deep foundation pit elevator shaft and sump pit, including a steel caisson support structure 1, a steel caisson water-proof structure 2 nested inside the steel caisson support structure 1, the steel caisson water-proof structure 2 being used to cooperate with the steel caisson support structure 1 in nested construction, a self-compacting concrete filling layer 3 filling the space between the steel caisson support structure 1 and the steel caisson structure, and an anti-buoyancy concrete layer 4 being poured on the outside of the steel caisson support structure 1.

[0019] The steel caisson support structure 1 includes a steel caisson body 101, connecting steel pipes 102, steel caisson lifting rings 103, and anti-buoyancy anchors 104. The steel caisson body 101 is constructed by welding channel steel keel and steel plate. Multiple connecting steel pipes 102 are welded to the inner side of the steel caisson body 101. Multiple steel caisson lifting rings 103 are fixedly installed on the top of the steel caisson body 101. Multiple anti-buoyancy anchors 104 are welded to the outer side of the steel caisson body 101. All anti-buoyancy anchors 104 penetrate into the interior of the anti-buoyancy concrete layer 4.

[0020] By nesting and cooperating the steel caisson support structure 001 and the steel caisson waterproofing structure 002, and pouring the self-compacting concrete filling layer 003, the device can achieve the effect of integrated support and waterproofing during construction. It creates a stable, dry, and enclosed working space in easily collapsible and highly permeable strata, solving the problem of failure of traditional single waterproofing technology and creating safe and reliable conditions for subsequent structural construction.

[0021] The steel caisson water-proof structure 2 includes a steel caisson body 201, keel supports 202, pressure relief holes 203, plugs 204, and steel caisson lifting rings 205. The steel caisson body 201 is constructed by welding channel steel keels and steel plates. Multiple keel supports 202 are provided on the inner surface of the steel caisson body 201. A pressure relief hole 203 is opened in the middle of the bottom plate of the steel caisson body 201. A plug 204 is movably installed on the surface of the pressure relief hole 203. Multiple steel caisson lifting rings 205 are fixedly connected between the outer side of the steel caisson body 201 and the steel caisson body 101.

[0022] By setting up pressure relief holes 203 and working in conjunction with the buried water pump system 005, and using the anti-buoyancy counterweight concrete layer 004 to provide external pressure, the process can achieve a graded anti-buoyancy effect that combines active pressure relief and passive counterweight during construction. This effectively resists the buoyancy of groundwater, ensures the structural stability of the steel caisson during installation and concrete pouring, and prevents it from floating or deforming.

[0023] The construction equipment also includes an independent anti-buoyancy steel caisson structure 6, which is used for non-nesting construction. The independent anti-buoyancy steel caisson structure 6 includes an independent caisson body 601, keel 602, connecting support components 603, and steel mesh 604. The independent caisson body 601 is welded from channel steel keel and steel plate. Multiple connecting support components 603 are fixedly installed outward from the bottom of the independent caisson body 601. The surface of each connecting support component 603 is provided with steel mesh 604. Multiple keels 602 are welded to the bottom of the independent caisson body 601 and the surface of the connecting support components 603.

[0024] By providing a nested installation of steel caisson support structure 1 and steel caisson waterproof structure 2, or by selecting an independent anti-buoyancy steel caisson structure 006 as a solution, the construction process can flexibly select the construction mode according to the actual geological conditions. Under conditions of good soil quality and low risk, the structure is simplified, materials and construction period are saved, and the economy and engineering adaptability of the process are improved.

[0025] The construction device also includes a buried water pump structure 5 installed at the bottom of the pit, used to pump out the water accumulated at the bottom of the steel caisson water-proof structure 2. The output end of the buried water pump structure 5 is equipped with a water pump pipe 7.

[0026] A construction process for a nested support molding construction device for deep foundation pit elevator shafts and sump pits includes the following steps: S1: First, investigate the geological and hydrological conditions of the construction area and formulate a specific construction plan; S2: Based on the actual situation, choose one of the following for construction and installation: a nested support structure consisting of steel caisson support structure 1 and steel caisson waterproofing structure 2, or a non-nested support structure consisting of independent anti-buoyancy steel caisson structure 6. When there is a risk of pit wall collapse, a nested support mode is implemented using steel caisson support structure 1 and steel caisson waterproof structure 2: steel caisson support structure 1 is processed and hoisted into the pre-set pit, and the soil is excavated in layers to sink it to the design elevation; then, anti-buoyancy anchor rods 104 are welded on the outside of the steel caisson and anti-buoyancy concrete layer 4 is poured; after the counterweight concrete has set, steel caisson waterproof structure 2 is hoisted into the inside of steel caisson support structure 1 and precisely positioned, and the two are welded and fixed by steel caisson lifting rings 205; self-compacting concrete is poured into the gap between the two to form self-compacting concrete filling layer 3. When the risk of pit wall collapse is low, the independent anti-buoyancy steel caisson structure 6 is used as a single non-nested support mode: the independent anti-buoyancy steel caisson structure 6 is processed, and a foundation pit slightly larger than its counterweight area is dug at the installation position. The independent anti-buoyancy steel caisson structure 6 is lowered into place and fixed by water injection or additional counterweight. Counterweight concrete is poured in the area enclosed by the connecting support member 603 at its bottom and around it for stabilization. S3: Utilize the pressure relief hole 203 of the steel caisson water-proof structure 2 or the internal space of the independent anti-buoyancy steel caisson structure 6, combined with the buried water pump structure 5 to pump out accumulated water and create a dry working environment. S4: Drain the water inside the box, carry out waterproofing layer construction, steel bar binding and concrete pouring, and complete the formation of the water sump or elevator shaft structure. S5: Select different methods for waterproofing the penetration joints based on the actual situation: For dewatering steel pipe wells: Install a water-stop sleeve with a water-stop steel plate 12 and a flange cover at the position where the well pipe penetrates the bottom plate, and construct an advanced water-stop bottom plate around the sleeve; construct two layers of waterproofing to ensure that the waterproofing layer ends are sealed on the water-stop steel plate 12; after dewatering stops, fill the well and seal the flange cover. For the support grid column: weld additional steel gusset plates and annular waterstop steel plates 12 at the predetermined elevation position of the column body; set up a post-cast area around the column, and set up waterstop steel plates 12 at the construction joint 11; when the structure is constructed in the later stage, cut off the grid column to the design elevation, weld the end plate and complete the waterproof layer sealing, and then pour the post-cast area concrete. S6: Well sealing construction: For dewatering wells that need to be abandoned, chemical grouting is used for sealing. Cement-water glass grout is injected into the formation around the well pipe through the drill pipe to form an overlapping consolidation and water-stopping area.

[0027] In step S2, after the independent anti-buoyancy steel caisson structure 6 sinks, a keel support 202 can be installed inside the independent caisson body 601 to reinforce the independent caisson body 601. At the same time, a pressure relief hole 203 can be opened in the middle of the bottom plate of the independent caisson body 601, and the pressure relief hole 203 can be sealed with a plug 204 to facilitate drainage through the pressure relief hole 203.

[0028] Once the steel caisson water-proof structure 2 or the independent anti-buoyancy steel caisson structure 6 is installed and the anti-buoyancy measures and counterweights meet the requirements, the accumulated water in the independent anti-buoyancy steel caisson structure 6 is drained first, and the installed keel support 202, plug 204 and other support structures are removed. Then, the inside and outside corners of the caisson are rounded with cement mortar before waterproofing and bottom plate structure construction are carried out to further ensure the anti-buoyancy capability of the nested support structure.

[0029] After the internal waterproofing of the steel caisson waterproofing structure 2 or the independent anti-buoyancy steel caisson structure 6 is completed, the reinforcement binding of the sump pit and elevator shaft structure and the concrete pouring are carried out. First, a raft structure formed by the upper raft plate 9 and the lower raft plate 10 is installed on the outside of the top of the steel caisson waterproofing structure 2 or the independent anti-buoyancy steel caisson structure 6. Then, a haunch reinforcement 8 is installed between the upper raft plate 9 and the lower raft plate 10. Subsequently, a waterstop steel plate 12 and a rubber waterstop strip 13 are inserted into the surface of the steel caisson waterproofing structure 2 or the independent anti-buoyancy steel caisson structure 6 to set the construction joint 11.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A construction device for nested support and molding of elevator shaft and sump pit in deep foundation pit, comprising a steel caisson support structure (1), characterized in that, The steel caisson support structure (1) is internally nested with a steel caisson waterproof structure (2). The steel caisson waterproof structure (2) is used to cooperate with the steel caisson support structure (1) in nested construction. A self-compacting concrete filling layer (3) is filled between the steel caisson support structure (1) and the steel caisson structure. An anti-buoyancy concrete layer (4) is poured on the outside of the steel caisson support structure (1).

2. The deep foundation pit elevator shaft and sump pit nested support forming construction device according to claim 1, characterized in that, The steel caisson support structure (1) includes a steel caisson body (101), connecting steel pipes (102), steel caisson lifting rings (103), and anti-buoyancy anchors (104). The steel caisson body (101) is constructed by welding channel steel keel and steel plate. Multiple connecting steel pipes (102) are welded to the inner side of the steel caisson body (101). Multiple steel caisson lifting rings (103) are fixedly installed on the top of the steel caisson body (101). Multiple anti-buoyancy anchors (104) are welded to the outer side of the steel caisson body (101). The anti-buoyancy anchors (104) all penetrate into the interior of the anti-buoyancy configuration concrete layer (4).

3. The deep foundation pit elevator shaft and sump pit nested support forming construction device according to claim 2, characterized in that, The steel caisson water-proof structure (2) includes a steel caisson body (201), a keel support (202), a pressure relief hole (203), a plug (204), and a steel caisson lifting ring (205). The steel caisson body (201) is constructed by welding a channel steel keel to a steel plate. Multiple keel supports (202) are provided on the inner surface of the steel caisson body (201). A pressure relief hole (203) is provided in the middle of the bottom plate of the steel caisson body (201). A plug (204) is movably installed on the surface of the pressure relief hole (203). Multiple steel caisson lifting rings (205) are fixedly connected between the outer side of the steel caisson body (201) and the steel caisson body (101).

4. The deep foundation pit elevator shaft and sump pit nested support forming construction device according to claim 3, characterized in that, The construction device also includes an independent anti-buoyancy steel caisson structure (6), which is used for non-nesting construction; The independent anti-buoyancy steel caisson structure (6) includes an independent caisson body (601), keel (602), connecting support components (603), and steel mesh (604). The independent caisson body (601) is welded from channel steel keel and steel plate. Multiple connecting support components (603) are fixedly installed on the bottom of the independent caisson body (601). The surface of the connecting support components (603) is provided with steel mesh (604). Multiple keels (602) are welded to the bottom of the independent caisson body (601) and the surface of the connecting support components (603).

5. The deep foundation pit elevator shaft and sump pit nested support forming construction device according to claim 4, characterized in that, The construction device also includes a buried water pump structure (5) installed at the bottom of the pit, used to pump out the water accumulated at the bottom of the steel caisson water-proof structure (2), and the output end of the buried water pump structure (5) is equipped with a water pump pipe (7).

6. A construction process for a nested support and forming construction device for deep foundation pit elevator shafts and sump pits according to claim 5, characterized in that, Includes the following steps: S1: First, investigate the geological and hydrological conditions of the construction area and formulate a specific construction plan; S2: Based on the actual situation, choose one of the following for construction and installation: a nested support structure consisting of a steel caisson support structure (1) and a steel caisson waterproofing structure (2), or a non-nested support structure consisting of an independent anti-buoyancy steel caisson structure (6). When there is a risk of collapse of the pit wall, a nested support mode is implemented with the steel caisson support structure (1) and the steel caisson water-proof structure (2): the steel caisson support structure (1) is processed and hoisted into the pre-set pit, and the soil is excavated in layers to sink it to the design elevation; then, anti-buoyancy anchor rods (104) are welded on the outside of the steel caisson and an anti-buoyancy configuration concrete layer (4) is poured; after the counterweight concrete has set, the steel caisson water-proof structure (2) is hoisted into the inside of the steel caisson support structure (1) and accurately positioned, and the two are welded and fixed by the steel caisson lifting ring (205); self-compacting concrete is poured into the gap between the two to form a self-compacting concrete filling layer (3). When the risk of pit wall collapse is low, the independent anti-buoyancy steel caisson structure (6) is used as the sole non-nested support mode: the independent anti-buoyancy steel caisson structure (6) is processed, and a foundation pit slightly larger than its counterweight area is dug at the installation position. The independent anti-buoyancy steel caisson structure (6) is sank into place and fixed by water injection or additional counterweight. Counterweight concrete is poured in the area enclosed by the connecting support member (603) at its bottom and around it for stabilization. S3: Utilize the pressure relief hole (203) of the steel caisson water-proof structure (2) or the internal space of the independent anti-buoyancy steel caisson structure (6) to pump out accumulated water in combination with the buried water pump structure (5) to create a dry working environment. S4: Drain the water inside the box, carry out waterproofing layer construction, steel bar binding and concrete pouring, and complete the formation of the water sump or elevator shaft structure. S5: Select different methods for waterproofing the penetration joints based on the actual situation: For dewatering steel pipe wells: install a water-stopping sleeve with a water-stopping steel plate (12) and a flange cover at the position where the well pipe passes through the bottom plate, and construct an advanced water-stopping bottom plate around the sleeve; construct two layers of waterproofing to ensure that the waterproofing layer ends are sealed on the water-stopping steel plate (12); after dewatering stops, fill the well and seal the flange cover. For the support grid column: weld additional steel gusset plates and annular waterstop steel plates (12) at the predetermined elevation of the column body; set up a post-casting area around the column, and set up waterstop steel plates (12) at the construction joint (11); when the structure is constructed later, cut off the grid column to the design elevation, weld the end plate and complete the waterproof layer sealing, and then pour the post-casting area concrete. S6: Well sealing construction: For dewatering wells that need to be abandoned, chemical grouting is used for sealing. Cement-water glass grout is injected into the formation around the well pipe through the drill pipe to form an overlapping consolidation and water-stopping area.

7. The construction process of the nested support and molding construction device for deep foundation pit elevator shaft and sump pit as described in claim 6, characterized in that, In step S2, after the independent anti-buoyancy steel caisson structure (6) sinks, a keel support (202) can be installed inside the independent caisson body (601) to reinforce the independent caisson body (601). At the same time, a pressure relief hole (203) can be opened in the middle of the bottom plate of the independent caisson body (601), and a plug (204) can be used to seal the pressure relief hole (203) to facilitate drainage through the pressure relief hole (203).

8. The construction process of the nested support molding construction device for deep foundation pit elevator shaft and sump pit according to claim 7, characterized in that, After the steel caisson waterproof structure (2) or independent anti-buoyancy steel caisson structure (6) is installed and the anti-buoyancy measures and counterweights meet the requirements, the water in the independent anti-buoyancy steel caisson structure (6) is drained first, and the installed keel support (202) and plug (204) and other support structures are removed. Then, the inside and outside corners of the caisson are rounded with cement mortar before waterproofing and bottom plate structure construction are carried out to further ensure the anti-buoyancy capacity of the nested support structure.

9. The construction process of the nested support and forming construction device for deep foundation pit elevator shaft and sump pit as described in claim 8, characterized in that, After the waterproofing construction of the steel caisson waterproof structure (2) or the independent anti-buoyancy steel caisson structure (6) is completed, the reinforcement binding of the water collection pit and elevator shaft structure and the concrete structure pouring are carried out. First, the raft structure formed by the raft top iron (9) and the raft bottom iron (10) is installed on the outside of the top of the steel caisson waterproof structure (2) or the independent anti-buoyancy steel caisson structure (6), and the haunch reinforcement (8) is installed between the raft top iron (9) and the raft bottom iron (10). Then, the water-stop steel plate (12) and the rubber water-stop strip (13) are inserted into the surface of the steel caisson waterproof structure (2) or the independent anti-buoyancy steel caisson structure (6) to set the construction joint (11).

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