Construction method of deep foundation pit large-slope toe supporting structure
By using a combination method of crane, pile puller and vibrating hammer in the construction of large-scale slope of deep foundation pits, the problem of difficulty in removing steel sheet piles is solved, and efficient and safe steel sheet pile removal is achieved, reducing construction period and cost.
Patent Information
- Application Number
- CN202510334436.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-20
- Publication Date
- 2025-06-13
AI Technical Summary
In the construction of large-scale slope of deep foundation pits, it is difficult to remove steel sheet piles, resulting in extended construction period and increased costs, and traditional methods affect the progress of structural construction.
The crane is used to remove the steel sheet piles by combining a vibrating hammer connected by a pile puller and a hydraulic high-pressure oil pipe. The forced vibration of the vibrating hammer destroys the cohesion of the soil around the steel sheet piles, overcomes the pile pulling resistance, and pulls out the piles through the crane's additional lifting force.
The safe and efficient removal of steel sheet piles has been achieved, the construction period has been reduced, the material investment and cost have been increased, and the progress and safety of basement structure construction have been ensured.
Smart Images
Figure CN120139232A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of building construction. Specifically, it relates to a construction method for the support structure of the toe of a large slope in a deep foundation pit. Background Art
[0002] Shotcrete and anchor support for the large slope of a deep foundation pit is a common support method in the excavation of building foundation pits. However, there are often some errors in the construction of the foundation pit slope, such as the toe construction not being in place and the slope gradient being inaccurate, which may lead to the situation that the foundation slab may eat into the bottom of the foundation pit support slope and the excavation of the bearing platform at the outer wall side may damage the bottom slope support of the pit. To ensure the safety and reliability of the bottom slope support during the excavation of the bearing platform at the outer wall side, steel sheet piles need to be driven at the bottom of the slope before the excavation of the bearing platform at the outer wall side to avoid the collapse of the bottom of the slope.
[0003] In view of the special situation where the toe of the large slope of a deep foundation pit is supported and the bearing platform structure extends into the toe of the slope, directly excavating the toe of the slope will affect the support safety. Using steel sheet pile support and extraction is a relatively economical method. For a large slope, the steel sheet piles can be driven into the bottom of the foundation pit. After the construction of the foundation structure is completed, a narrow effective space will be formed between the basement exterior wall and the bottom of the foundation pit slope. Due to the influence of the foundation structure at the bottom of the pit, it is difficult to extract the steel sheet piles, and the pile extractor has no effective working space. How to extract the steel sheet piles is a construction problem. The traditional treatment method can reduce the size of the bearing platform structure or use wooden piles to support the bottom of the pit temporarily. Reducing the size of the bearing platform structure may affect the size of the foundation, but the support depth is limited. Driving the steel sheet piles at the bottom of the slope of the pit increases the support depth and does not affect the size of the bearing platform, but the technical problem of steel sheet pile extraction still needs to be considered. The traditional method of extracting steel sheet piles is to use a pile extractor. After the foundation slab is poured and its strength meets the requirements, the pile extractor walks on the slab. However, this method will affect the construction period of the structure, easily lead to the phenomenon of workers being idle, and the steel sheet piles are faced with the problem of narrow surrounding space. Due to the deep bottom of the pit, it is difficult to extract the piles. If not extracted, the investment cost will increase. Therefore, a construction method for the support structure of the toe of a large slope in a deep foundation pit is needed to prevent the collapse of the toe of the slope and solve the technical problem that the pile extractor cannot reach the bottom of the pit, resulting in difficulty in extracting the steel sheet piles. Summary of the Invention
[0004] The purpose of the present invention is to provide a construction method for the support structure of the toe of a large slope in a deep foundation pit to prevent the collapse of the toe of the slope, solve the technical problem that the pile extractor cannot reach the bottom of the pit, resulting in difficulty in extracting the steel sheet piles, ensure the safety of the excavation of the bottom slope of the pit, save the construction period of the basement structure, do not affect the structure construction, and at the same time reduce the investment in support costs, achieving the purpose of recycling the steel sheet piles.
[0005] To achieve the above purpose, the present invention adopts the following technical solutions: A construction method for the support structure of the toe of a large slope in a deep foundation pit includes the following steps: (1) Positioning and laying out the bottom of a large slope: measuring and laying out the edge lines of the steel sheet piles required to be driven; (2) Driving steel sheet piles at the bottom of the pit: Driving steel sheet piles according to the steel sheet pile edge line measured in step (1); (3) Construction of brick membrane and foundation slab structure; (4) Construct waterproof and waterproof protective layer at the inner corner of the exterior wall, backfill with stone powder, and pour C15 plain concrete; (5) Construct the basement structure and build the waterproof and protective layer on the outer wall of the basement. After the construction is completed, the outer frame of the basement is removed. At this time, the construction of the steel sheet pile support structure is completed to form a steel sheet pile support structure; (6) Remove the steel sheet piles and complete the construction of the slope foot support structure for the deep foundation pit.
[0006] The specific implementation process of step (1) is as follows: according to the bottom edge of the foundation pit and the outer edge of the pedestal brick formwork, the range of the pedestal and bottom plate brick formwork that penetrates into the bottom of the foundation pit is matched, and the steel sheet pile edge line is designed in depth according to the range, and the steel sheet pile edge line that needs to be driven is measured and laid out according to the detailed drawing.
[0007] The specific implementation process of step (2) is as follows: the steel sheet piles are driven in accordance with the laid-out edge line, and the steel sheet piles are sunk by the vibration method. Before sinking the piles, the sprayed anchor surface layer is first broken with a pneumatic pick, and the exposed soil nails, anchor rods and steel mesh are removed to prevent the entire steel mesh surface layer from being cracked during the steel sheet pile driving process.
[0008] The specific implementation process of step (3) is as follows: first, the brick membrane is constructed. When constructing the brick membrane, first, measurement and layout and foundation excavation are carried out, then pile cutting and cushion layer pouring are carried out, and finally, the brick membrane is built. When the brick membrane is built, plaster is applied on the inner side of the brick membrane and earth is backfilled in layers on the outer side of the brick membrane. The backfill height is the bottom mark height of the foundation slab cushion layer. After the brick membrane is built, the foundation slab structure is constructed. During the specific construction, the basement slab is waterproofed first, then the slab steel bars are tied, and finally the slab concrete is poured to complete the construction of the brick membrane and the foundation slab structure.
[0009] The specific operation process of step (4) is as follows: after the bottom plate concrete is poured, the waterproof and waterproof protective layer of the inner corner of the external wall is constructed in time, the groove formed between the foundation bottom plate and the steel sheet pile is backfilled with stone powder, and then a 100 mm thick C15 plain concrete is poured to press the top.
[0010] The specific operation process of step (5) is as follows: after the backfilling and hardening process in the groove formed between the foundation slab and the steel sheet piles is completed, the double-row ground-type scaffolding of the basement is set up to construct the basement structure. After the construction of the basement structure is completed, the waterproof layer construction and waterproof protective layer masonry of the basement exterior wall are completed in time. After the masonry is completed, the basement scaffolding is removed.
[0011] The specific process of step (6) is as follows: It includes the following sub-steps: ① Positioning of mechanical equipment: The truck crane and the pile extractor are in place at the top of the slope. The vibrating hammer is connected to the pile extractor through an extended hydraulic oil pump pipe. The pile extractor controls the continuous vibration of the vibrating hammer through the hydraulic oil pump pipeline. The lifting wire rope hook of the truck crane holds the vibrating hammer, and the vibrating hammer is lowered to the position of the steel sheet pile at the bottom of the foundation pit. The chuck of the vibrating hammer clamps the pile head of the steel sheet pile to prepare for positioning. ② Personnel positioning: At least one commander at the top of the foundation pit sends instructions and signals. One crane driver and one pile extractor driver control the crane and the pile extractor machinery. At least one slinger cooperates in installing the crane hook. At least two porters cooperate in moving the vibrating hammer at the bottom of the foundation pit and transporting the extracted steel sheet piles, and promptly backfill the pile holes of the steel sheet piles. ③ Extracting the steel sheet piles: The hydraulic vibrating pile hammer is hung under the crane hook and slowly sent to the position of the steel sheet pile at the bottom of the foundation pit. The hammer head clamps the head of the steel sheet pile. After the operators are in place and listen to the signals sent by the commander, all the operators at the bottom of the pit move away. First, start the pile driver / extractor, and transmit the exciting force to the hydraulic vibrating pile hammer through the extended high-pressure hydraulic oil pipe. The hammer head clamps the head of the steel sheet pile and vibrates for 1 min to 2 min. After the pile head is loosened, the crane starts to slowly retract the hook upward, causing the steel sheet pile to be gradually vibrated and pulled out. ④ Treatment of the soil hole of the steel sheet pile: After the steel sheet pile is pulled out of the pile hole, backfill the pile hole left after pulling out the pile. The remaining voids after backfilling should be promptly filled with 1:1 cement slurry or compacted with medium-coarse sand to complete the pile extraction.
[0012] The steel sheet pile support structure formed in step (5) includes several steel sheet piles vertically arranged downward on the foundation pit slope. The several steel sheet piles are arranged side by side. The upper ends of the steel sheet piles extend out of the foundation pit slope. A foundation slab is arranged on the right side of the steel sheet pile. A bearing platform is arranged below the foundation slab. A first cushion layer is arranged at the bottom of the bearing platform. The first cushion layer is arranged at the bottom of the foundation pit. A waterproof protective layer is arranged on the top of the foundation slab. The upper end of the foundation slab is connected to the basement exterior wall. The waterproof protective layer is arranged on the left side of the basement exterior wall. A backfill stone powder area and a bottom slab brick formwork are arranged between the left end of the foundation slab and the right side surface of the steel sheet pile. The backfill stone powder area is located on the left side of the bottom slab brick formwork. The bottom slab brick formwork is arranged on the left end surface of the foundation slab. A backfill plain soil area and a first bearing platform brick formwork are arranged between the left end of the bearing platform and the steel sheet pile. The first bearing platform brick formwork is arranged on the left end of the bearing platform.
[0013] The gap between the backfill plain soil area and the backfill stone powder area is filled with a second cushion layer. A second bearing platform brick formwork is arranged at the right end of the bearing platform. The bottom ends of the first bearing platform brick formwork and the second bearing platform brick formwork are both arranged on the first cushion layer.
[0014] A water-stop steel sheet is arranged inside the basement exterior wall. A concrete compression top layer is arranged at the upper end of the backfill stone powder area.
[0015] This application is a construction method for partially excavating the supporting slope to enhance the stability and safety of the foundation pit when the overlap between the bearing platform and the supporting slope at the bottom of the foundation pit in a narrow space affects the construction of the floor structure. Specifically, it is mainly used during the excavation of the slope support in the narrow part of the deep foundation pit to prevent the loss, sliding, and collapse of the soil at the bottom of the foundation pit and ensure the safety of the surrounding structures and construction personnel of the foundation pit.
[0016] After the casting of the floor concrete is completed, the waterproofing and waterproof protective layer at the external wall corner are constructed in a timely manner. First, the narrow space formed between the foundation floor and the steel sheet piles is backfilled with stone powder, which helps to stabilize the trench and prevent soil movement and settlement. Then, a 100-mm-thick C15 plain concrete capping is poured on the top of the stone powder. On the one hand, it reduces the situation of soil being carried out when pulling out the steel sheet piles later, thereby reducing the impact on the safety of the slope support; on the other hand, the concrete capping can serve as the foundation for the vertical poles of the external scaffold of the basement and also serve as the drainage ditch around the foundation pit, thus ensuring the smooth progress of the construction of the external wall structure and the external wall waterproofing of the basement.
[0017] This application has been optimized and innovated in the traditional construction methods of basement structures and the extraction of steel sheet piles. A crane is used in cooperation with a pile driving and extracting machine, and a vibratory hammer connected to an extended hydraulic high-pressure oil pipe is used to extract the piles: by using the forced vibration generated by the vibratory hammer to disturb the soil quality and break the cohesion of the soil around the steel sheet piles to overcome the pile extraction resistance, and relying on the additional lifting force of the crane to extract the piles.
[0018] In summary, this application is simple and easy to implement. By using the Larsen steel sheet piles for secondary support, it solves the problem of the conflict between the deep foundation pit bearing platform and the foundation pit support slope, ensuring the safety of the basement structure construction and the foundation pit support; at the slope top, by using a crane in cooperation with a pile driving and extracting machine and a vibratory hammer connected to an extended hydraulic high-pressure oil pipe to extract the piles, it ensures the construction progress of the basement structure, reduces the construction period, avoids the use of disposable materials, and achieves the purpose of improving efficiency. Brief Description of the Drawings
[0019] Figure 1 is the structural schematic diagram of the positioning and driving of the steel sheet piles of the present invention.
[0020] Figure 2 is Figure 1 the enlarged view of part A in
[0021] Figure 3 is the structural schematic diagram of the construction of the brick formwork and the foundation floor of the present invention.
[0022] Figure 4 is Figure 3 the enlarged view of part B in
[0023] Figure 5It is a structural schematic diagram of backfilling stone powder and pouring C15 plain concrete in the present invention.
[0024] Figure 6 yes Figure 5 Enlarged view of part C in the middle.
[0025] Figure 7 It is a structural schematic diagram of removing steel sheet piles according to the present invention.
[0026] Figure 8 yes Figure 7 Enlarged view of part D in the middle. DETAILED DESCRIPTION
[0027] The embodiments of the present invention are further described below with reference to the accompanying drawings.
[0028] like Figure 1-8 As shown, a method for constructing a deep foundation pit large slope foot support structure comprises the following steps: (1) Positioning and laying out the bottom of the slope: measuring and laying out the edge line of the steel sheet piles to be driven; (2) Driving steel sheet piles 1 at the bottom of the pit: Driving steel sheet piles 1 according to the edge lines of the steel sheet piles 1 measured and laid out in step (1); (3) Construction of brick membrane and foundation slab 3 structure; (4) Construct waterproof and waterproof protective layer at the inner corner of the exterior wall, backfill with stone powder, and pour C15 plain concrete; (5) Construct the basement structure and build the waterproof and protective layer on the basement outer wall 7. After the construction is completed, the basement outer frame is removed. At this time, the construction of the steel sheet pile 1 support structure is completed to form the steel sheet pile 1 support structure; (6) Remove the steel sheet piles 1 and complete the construction of the deep foundation pit large slope foot support structure. Due to the narrow space of the basement and the deep foundation pit, the equipment cannot use conventional construction methods to remove the steel sheet piles 1 from the bottom (or top). Therefore, a crane is used in conjunction with a pile driver 12 and a vibrator 15 connected to an extended hydraulic high-pressure oil pipe to pull out the piles: the forced vibration generated by the vibrator 15 is used to disturb the soil and destroy the cohesion of the soil around the steel sheet pile 1 to overcome the resistance to pile extraction. The piles are then pulled out by relying on the additional lifting force of the crane.
[0029] The specific implementation process of step (1) is as follows: according to the bottom edge of the foundation pit and the outer edge of the brick formwork of the pedestal 4, the range of the pedestal 4 and the bottom plate brick formwork that enter the bottom of the foundation pit is found, and according to the range, the edge line of the steel sheet pile 1 is designed in depth, and the edge line of the steel sheet pile 1 that needs to be driven is measured and laid out according to the detailed drawing.
[0030] The specific implementation process of step (2) is as follows: the steel sheet pile 1 is driven in accordance with the laid-out edge line, the steel sheet pile 1 is sunk by the vibration method, and before sinking the pile, the sprayed anchor surface layer is first broken by a pneumatic pick, and the exposed soil nails, anchor rods and steel mesh are removed to prevent the entire steel mesh surface layer from being cracked during the driving process of the steel sheet pile 1.
[0031] The specific implementation process of step (3) is as follows: first, the brick membrane is constructed. When constructing the brick membrane, first, measurement and layout and excavation of the pedestal 4 are carried out, then pile cutting and cushion layer pouring are carried out, and finally the brick membrane is built. When the brick membrane is built, plaster is applied on the inner side of the brick membrane and earth is backfilled in layers on the outer side of the brick membrane. The backfill height is the bottom mark height of the cushion layer of the foundation slab 3. After the brick membrane is built, the foundation slab 3 structure is constructed. During the specific construction, the basement slab is waterproofed first, then the slab steel bars are tied, and finally the slab concrete is poured to complete the construction of the brick membrane and the foundation slab 3 structure.
[0032] The specific operation process of step (4) is as follows: after the bottom plate concrete is poured, the waterproof and waterproof protective layer 6 of the inner corner of the outer wall is constructed in time, the groove formed between the foundation bottom plate 3 and the steel sheet pile 1 is backfilled with stone powder, and then a 100 thick C15 plain concrete is poured to form a concrete pressure top layer. On the one hand, it reduces the situation where the steel sheet pile 1 is pulled out with soil in the later stage, and on the other hand, the concrete pressure top can be used as the foundation of the basement external frame pole and also as a drainage ditch around the foundation pit.
[0033] The specific operation process of step (5) is as follows: after the backfilling and hardening process in the groove formed between the foundation slab 3 and the steel sheet pile 1 is completed, the double-row ground-type scaffolding of the basement is set up to construct the basement structure. After the basement structure is completed, the waterproof layer construction of the basement outer wall 7 and the masonry of the waterproof protective layer 6 are completed in time. After the masonry is completed, the basement scaffolding is removed. Provide working conditions for the removal of the steel sheet pile 1 as soon as possible, reduce the rental fee of the steel sheet pile 1, and reduce the construction cost.
[0034] The specific process of step (6) is as follows: ① Mechanical equipment is in place: the truck crane 13 and the pile puller 12 are ready at the top of the slope, the vibratory hammer 15 is connected to the pile puller 12 through the extended hydraulic oil pump pipe 14, the pile puller 12 controls the vibratory hammer 15 to vibrate continuously through the hydraulic oil pump pipe 14, the truck crane 13 hoists the vibratory hammer 15 with a lifting wire rope hook, and lowers the vibratory hammer 15 to the position of the steel sheet pile 1 at the bottom of the foundation pit, and the vibratory hammer 15 clamps the pile head of the steel sheet pile 1, ready to be in place; ② Personnel are in place: at least one commander at the top of the foundation pit sends instructions and signals, a crane driver and a pile puller 12 driver control the crane and pile puller 12 machinery, at least one rigger cooperates to install the crane hook, and at least two porters cooperate to move the vibrating hammer 15 at the bottom of the foundation pit, and transport the pulled steel sheet piles 1, and backfill the pile holes of the steel sheet piles 1 in time; ③Pull out the steel sheet pile 1: Hang a hydraulic vibration pile hammer under the crane hook, slowly lower it to the position of the steel sheet pile 1 at the bottom of the foundation pit, and clamp the head of the steel sheet pile 1 with the hammer head. After the operators are in place, listen to the signals sent by the commander, and all the operators at the bottom of the pit stay away. First, start the pile driver / extractor 12, transfer the exciting force to the hydraulic vibration pile hammer through the extended high-pressure hydraulic oil pipe, clamp the head of the steel sheet pile 1 with the hammer head and vibrate for 1 min to 2 min. After the pile head becomes loose, the crane starts to slowly retract the hook upward, causing the steel sheet pile 1 to be gradually vibrated and pulled out; ④Treatment of the soil holes of the steel sheet pile 1: After the steel sheet pile is pulled out of the pile hole, backfill the pile holes left after pulling out the piles. The remaining gaps after backfilling should be promptly filled with 1:1 cement slurry or compacted with medium-coarse sand to complete the pile pulling. After repairing the holes, it is necessary to conduct a comprehensive inspection of the steel sheet pile 1 to ensure that there are no damages or defects. Evaluate the entire pile pulling process, record the data and observed phenomena, conduct analysis and summary, and provide experience and lessons for subsequent operations. Finally, transport the recovered steel sheet pile 1 to the designated location and handle it properly to ensure the effective utilization of resources. Summarize the process of pulling out the steel sheet pile 1, find the deficiencies and make improvements to further improve work efficiency and quality.
[0035] The steel sheet pile 1 support structure formed in step (5) includes several steel sheet piles 1 vertically arranged downward on the foundation pit slope 2. The several steel sheet piles 1 are arranged side by side. The upper end of the steel sheet pile 1 extends out of the foundation pit slope 2. A foundation slab 3 is arranged on the right side of the steel sheet pile 1. A bearing platform 4 is arranged below the foundation slab 3. A first cushion layer 5 is arranged at the bottom of the bearing platform 4. The first cushion layer 5 is arranged at the bottom of the foundation pit. A waterproof protective layer 6 is arranged on the top of the foundation slab 3. The upper end of the foundation slab 3 is connected to the basement exterior wall 7. The waterproof protective layer 6 is arranged on the left side of the basement exterior wall 7. A backfilled stone powder area 8 and a bottom slab brick formwork 9 are arranged between the left end of the foundation slab 3 and the right side surface of the steel sheet pile 1. The backfilled stone powder area 8 is located on the left side of the bottom slab brick formwork 9. The bottom slab brick formwork 9 is arranged on the left end surface of the foundation slab 3. A backfilled plain soil area 10 and a first bearing platform brick formwork 11 are arranged between the left end of the bearing platform 4 and the steel sheet pile 1. The first bearing platform brick formwork 11 is arranged on the left end of the bearing platform 4.
[0036] The gap between the backfilled plain soil area 10 and the backfilled stone powder area 8 is filled with a second cushion layer 16. A second bearing platform brick formwork 17 is arranged at the right end of the bearing platform 4. The bottom ends of the first bearing platform brick formwork 11 and the second bearing platform brick formwork 17 are both arranged on the first cushion layer 5.
[0037] A water stop steel sheet 18 is arranged inside the basement exterior wall 7. A concrete compression top layer 19 is arranged at the upper end of the backfilled stone powder area 8.
[0038] This application is a construction method for partially excavating the support slope to enhance the stability and safety of the foundation pit when the bottom of the foundation pit in a narrow space is affected by the overlap of the cap 4 and the support slope, which is used in the process of supporting and excavating the slope of the deep foundation pit with narrow space to prevent the loss, sliding and collapse of the soil at the bottom of the foundation pit, and ensure the safety of the surrounding structures and construction personnel of the foundation pit.
[0039] After the concrete pouring of the bottom plate is completed, the waterproof and waterproof protective layer 6 of the inner corner of the outer wall is constructed in time. The narrow space formed between the foundation bottom plate 3 and the steel sheet pile 1 is first backfilled with stone powder, which helps to stabilize the groove and prevent soil movement and settlement. Then a 100mm thick C15 plain concrete cap is poured on top of the stone powder. On the one hand, it reduces the situation that the soil is entrained when the steel sheet pile 1 is pulled out later, thereby reducing the impact on the safety of the slope support; on the other hand, the concrete cap can serve as the foundation of the basement external frame pole, and also serves as a drainage ditch around the foundation pit, thereby ensuring the smooth construction of the basement external wall 7 structure and external wall waterproofing.
[0040] The present application optimizes and innovates the traditional basement structure construction and steel sheet pile 1 removal construction method, and uses a crane in conjunction with a pile driver 12 and a vibrator 15 connected to an extended hydraulic high-pressure oil pipe to pull out the piles: the forced vibration generated by the vibrator 15 is used to disturb the soil and destroy the cohesion of the soil around the steel sheet pile 1 to overcome the pile pulling resistance, and the piles are pulled out by relying on the additional lifting force of the crane.
[0041] In summary, the present application is simple and easy to implement. By using Larsen steel sheet piles 1 for secondary support, the conflict between the deep foundation pit cap 4 and the foundation pit support slope is solved, thereby ensuring the safety of the basement structure construction and the foundation pit support. At the top of the slope, a crane is used in conjunction with a pile driver 12 and a vibrating hammer 15 connected to an extended hydraulic high-pressure oil pipe to pull piles, thereby ensuring the progress of the basement structure construction, reducing the construction period, avoiding the use of disposable materials, and achieving the purpose of improving efficiency.
[0042] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.
Claims
1. A method for constructing a deep foundation pit large slope foot support structure, characterized in that: The steps include: (1) Positioning and laying out the bottom of a large slope: measuring and laying out the edge lines of the steel sheet piles required to be driven; (2) Driving steel sheet piles at the bottom of the pit: Driving steel sheet piles according to the steel sheet pile edge line measured in step (1); (3) Construction of brick membrane and foundation slab structure; (4) Construct waterproof and waterproof protective layer at the inner corner of the exterior wall, backfill with stone powder, and pour C15 plain concrete; (5) Construct the basement structure and build the waterproof and protective layer on the outer wall of the basement. After the construction is completed, the outer frame of the basement is removed. At this time, the construction of the steel sheet pile support structure is completed to form a steel sheet pile support structure; (6) Remove the steel sheet piles and complete the construction of the slope foot support structure for the deep foundation pit.
2. A method for constructing a deep foundation pit large slope foot support structure according to claim 1, characterized in that: The specific implementation process of step (1) is as follows: according to the bottom edge of the foundation pit and the outer edge of the pedestal brick formwork, the range of the pedestal and bottom plate brick formwork that penetrates into the bottom of the foundation pit is matched, and the steel sheet pile edge line is designed in depth according to the range, and the steel sheet pile edge line that needs to be driven is measured and laid out according to the detailed drawing.
3. A method for constructing a deep foundation pit large slope foot support structure according to claim 2, characterized in that: The specific implementation process of step (2) is as follows: the steel sheet piles are driven in accordance with the laid-out edge line, and the steel sheet piles are sunk by the vibration method. Before sinking the piles, the sprayed anchor surface layer is first broken with a pneumatic pick, and the exposed soil nails, anchor rods and steel mesh are removed to prevent the entire steel mesh surface layer from being cracked during the steel sheet pile driving process.
4. A method for constructing a deep foundation pit large slope foot support structure according to claim 3, characterized in that: The specific implementation process of step (3) is as follows: first, the brick membrane is constructed. When constructing the brick membrane, first, measurement and layout and foundation excavation are carried out, then pile cutting and cushion layer pouring are carried out, and finally, the brick membrane is built. When the brick membrane is built, plaster is applied on the inner side of the brick membrane and earth is backfilled in layers on the outer side of the brick membrane. The backfill height is the bottom mark height of the foundation slab cushion layer. After the brick membrane is built, the foundation slab structure is constructed. During the specific construction, the basement slab is waterproofed first, then the slab steel bars are tied, and finally the slab concrete is poured to complete the construction of the brick membrane and the foundation slab structure.
5. A method for constructing a deep foundation pit large slope foot support structure according to claim 4, characterized in that: The specific operation process of step (4) is as follows: after the bottom plate concrete is poured, the waterproof and waterproof protective layer of the inner corner of the external wall is constructed in time, the groove formed between the foundation bottom plate and the steel sheet pile is backfilled with stone powder, and then a 100 mm thick C15 plain concrete is poured to press the top.
6. A method for constructing a deep foundation pit large slope foot support structure according to claim 5, characterized in that: The specific operation process of step (5) is as follows: after the backfilling and hardening process in the groove formed between the foundation slab and the steel sheet piles is completed, the double-row ground-type scaffolding of the basement is set up to construct the basement structure. After the construction of the basement structure is completed, the waterproof layer construction and waterproof protective layer masonry of the basement exterior wall are completed in time. After the masonry is completed, the basement scaffolding is removed.
7. A method for constructing a deep foundation pit large slope foot support structure according to claim 6, characterized in that: The specific process of step (6) is as follows: ① Mechanical equipment is in place: the truck crane and pile puller are ready at the top of the slope, the vibratory hammer is connected to the pile puller through the extended hydraulic oil pump pipe, the pile puller controls the vibratory hammer to vibrate continuously through the hydraulic oil pump pipeline, the truck crane hoists the vibratory hammer with a heavy wire rope hook, and lowers the vibratory hammer to the position of the steel sheet pile at the bottom of the foundation pit, the vibratory hammer chuck clamps the steel sheet pile head, and is ready to be in place; ② Personnel in place: at least one commander at the top of the foundation pit sends instructions and signals, one crane driver and one pile puller driver control the crane and pile puller machinery, at least one rigger cooperates to install the crane hook, and at least two porters cooperate to move the vibrating hammer at the bottom of the foundation pit, and transport the pulled steel sheet piles, and backfill the steel sheet pile holes in time; ③ Pull out the steel sheet piles: Hang a hydraulic vibration pile hammer under the crane hook and slowly send it to the position of the steel sheet pile at the bottom of the foundation pit. The hammer head clamps the head of the steel sheet pile. After the workers are in place, listen to the signal sent by the commander. All the workers at the bottom of the pit stay away. Start the pile driver first, and transmit the exciting force to the hydraulic vibration pile hammer through the extended hydraulic high-pressure oil pipe. The hammer head clamps the head of the steel sheet pile and vibrates for 1min to 2min. After the pile head is loosened, the crane starts to slowly retract the hook upwards, so that the steel sheet pile is gradually vibrated upwards; ④ Treatment of soil holes of steel sheet piles: After the steel plate is pulled out of the pile hole, the pile hole left after the pile extraction is backfilled. The remaining gaps after backfilling should be filled with 1:1 cement slurry or compacted with medium-coarse sand in time to complete the pile extraction.
8. A method for constructing a deep foundation pit large slope foot support structure according to claim 7, characterized in that: The steel sheet pile support structure formed in step (5) includes a plurality of steel sheet piles vertically downwardly arranged on the foundation pit slope, the plurality of steel sheet piles are arranged side by side front and back, the upper ends of the steel sheet piles extend out of the foundation pit slope, a foundation slab is arranged on the right side of the steel sheet piles, a cap is arranged at the lower part of the foundation slab, a first cushion layer is arranged at the bottom of the cap, the first cushion layer is arranged at the bottom of the foundation pit, a waterproof protective layer is arranged on the top of the foundation slab, the upper end of the foundation slab is connected to the basement outer wall, the waterproof protective layer is arranged on the left side of the basement outer wall, a backfill stone powder area and a base brick membrane are arranged between the left end of the foundation slab and the right side of the steel sheet pile, the backfill stone powder area is located on the left side of the base brick membrane, the base brick membrane is arranged on the left end face of the foundation slab, a backfill soil area and a base brick membrane are arranged between the left end of the cap and the steel sheet pile, and the base brick membrane is arranged on the left end of the cap.
9. A method for constructing a deep foundation pit large slope foot support structure according to claim 8, characterized in that: The gap between the backfilled soil area and the backfilled stone powder area is filled with a second cushion layer, a second pedestal brick membrane is arranged at the right end of the pedestal, and the bottom ends of the first pedestal brick membrane and the second pedestal brick membrane are both arranged on the first cushion layer.
10. A method for constructing a deep foundation pit large slope foot support structure according to claim 9, characterized in that: Waterstop steel plates are installed inside the outer walls of the basement, and a concrete top layer is installed on the top of the backfill stone powder area.