A splicing type I-beam composite structure and method for foundation pit engineering

Abstract

The present application relates to a kind of for foundation pit engineering splicing I-beam combined structure and method, the structure includes first section, intermediate standard section and bottom section, first section, intermediate standard section and bottom section are connected by lock mouth with Larsen steel sheet pile, form retaining and water stop structure, after construction is completed, can all be recycled, can be reused, construction area land can continue to be used, without clearing obstacle.The present application also solves the problem that long time welding is needed for traditional supporting structure H-shaped steel splicing by using splicing structure, saves construction period, facilitates construction;The structure forms continuous retaining and water stop steel wall with Larsen steel sheet pile, strong structural rigidity protects internal construction safety of foundation pit, prevents water and soil loss outside pit, after construction is completed, is removed and recycled, can be reused, and it does not produce any pollution to environment, also does not affect secondary development and utilization of the place land later, it is a kind of green, safe, economic, environmental protection structure system.

Description

Technical Field

[0001] This invention relates to the field of foundation pit engineering, and in particular to a recyclable and reusable modular I-beam composite structure, which serves as a support component to form a continuous steel wall for retaining soil and stopping water. Background Technology

[0002] To ensure land utilization, the setback distance from the building boundary is generally 3m, and basements are typically one or two stories. In this case, the conventional method for foundation pit support is to use cement-soil mixing piles with H-beams inserted. This involves using mixing machinery to mix and solidify cement and soil to form a reinforcing body, and then inserting H-beams as support components before solidification. The length of the H-beams is generally 9-12m. In areas with deeper pits or other locally deepened areas, the standard length of the H-beams may not meet the load-bearing requirements, necessitating on-site welding extensions. However, this process compromises the verticality and welding quality of the H-beams, and the welding time is lengthy. Furthermore, the mixed material solidifies over time, affecting the insertion of the H-beams. After the foundation pit is completed, the H-beams are removed, but the remaining mixed material cannot be reused, resulting in resource waste. Additionally, the cement mixing process pollutes the soil and groundwater, and the mixed material becomes an obstacle after the foundation pit is completed, reducing the land's secondary utilization rate. Summary of the Invention

[0003] This invention proposes a modular I-beam assembly structure and method for foundation pit engineering to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the technical solution of the present invention is: a modular I-beam composite structure for foundation pit engineering, comprising a first section, intermediate standard sections and a bottom section, wherein the first section, intermediate standard sections and bottom section are connected to Larssen steel sheet piles through interlocking joints to form a retaining and water-stopping structure, which can be fully recycled and reused after construction, and the land in the construction area can continue to be used without clearing obstacles.

[0005] Furthermore, the modular I-beam structure consists of front I-beams, rear I-beams, an intermediate connecting truss, and interlocking joints. The front I-beam 1 and rear I-beam 2 are made of I-beams ranging from No. 10 to No. 40, depending on the stress conditions of the foundation pit. The webs of the I-beams are welded together with 20mm thick steel plates to form a "Z"-shaped truss structure. The height of the "Z"-shaped truss structure increases sequentially from 500mm and 600mm to 1000mm according to customized production modules. The top and bottom steel plates of the "Z"-shaped truss structure... The width is 100mm, and the width of the remaining steel plates is 50mm; the bottom splicing positions of the front and rear I-beams are staggered with unequal lengths to avoid the risk of breakage on the same horizontal plane; the first section is arranged with lengths of 6m and 9m respectively to ensure that the joint position is below the bottom of the foundation pit, so as to avoid the area of ​​the foundation pit with the greatest stress. Flange bolt holes and web bolt holes are arranged at the bottom of the front and rear sections of the first section and the truss connecting steel plates to facilitate the connection with the next standard prefabricated combined structure.

[0006] Furthermore, the intermediate standard section is 3m high, and the front and rear I-beams are consistent with the first section, with the staggered peak position consistent with the bottom of the first section. Flange bolts and web bolt holes are provided in the front and rear I-beams and the web plate. The upper and lower sections are connected by flange connecting steel plates, web connecting steel plates, truss connecting steel plates and corresponding high-strength bolts. The width of the steel plates at the top and bottom of the truss is 100mm, and the width of the remaining steel plates is 50mm.

[0007] Furthermore, the bottom section is 3m high, and the front and rear I-beams are consistent with the standard section, with the staggered peak position consistent with the bottom end of the standard section. Flange bolts are provided on the front and rear I-beams, and web bolt holes are provided in the web plates. The width of the steel plates at the top and bottom of the truss is 100mm, and the width of the remaining steel plates is 50mm. At the same time, an "X" shaped cross is provided at the end section to enhance the overall rigidity when the bottom is inserted into the soil. The bottom ends of the front and rear I-beams are tapered at 45 degrees to form "V" shaped bottom ends, which facilitates insertion into the soil and reduces resistance.

[0008] Furthermore, the modular I-beam composite structure is provided with Larssen sheet pile interlocking joints on both sides, which overlap with the Larssen sheet piles to form a continuous retaining and water-stopping steel wall. The spacing of the modular I-beam composite structure and the number of Larssen sheet piles are adjusted according to the stress requirements based on a 400mm module.

[0009] A construction method for using a modular I-beam composite structure for foundation pit engineering as foundation pit support, the construction steps of which are as follows:

[0010] Step 1: Based on the internal force calculation results of the foundation pit, select a suitable modular I-beam composite structure. Its model and overall length should meet the requirements of the internal force and stability of the foundation pit support. At the same time, the splice joint should be set at a position where the bending moment of the foundation pit is smaller.

[0011] Step 2: The modular I-beam composite structure is prefabricated in the factory and transported to the site. Trial assembly is carried out on site. The verticality and flatness after assembly are required to reach 1 / 1000. The bolt holes are aligned to ensure installation. The steel sheet piles are checked for lock joints and grease is applied.

[0012] Step 3: After accurate positioning, use machinery to hoist the bottom section of the modular I-beam structure to the designated position. After adjusting the verticality, use a vibratory hammer to vibrate and press down until the bottom section is 1m above the ground. Then assemble the middle section and the first section using connecting steel plates and high-strength bolts.

[0013] Step 4: After the assembly is completed, continue to vibrate and press down until the middle standard section and the first section are exposed 1m above the ground. The first section is exposed 200mm above the ground to facilitate later extraction and recycling, and at the same time to prevent surface water from entering the foundation pit.

[0014] Step 7: After one section of the modular I-beam structure is completed, Larssen sheet piles are driven on both sides. After hoisting them to the interlocking position of the modular I-beam structure, align them with the interlocking position, adjust the plumb, and then vibrate the vibratory hammer to press them down to the designated position. Then, the next section of the modular I-beam structure is installed. This process is repeated until the entire foundation pit is completed. Corner sheet piles are used as closing ends at the corners to ensure the sealing of the entire foundation pit for water stopping and soil retention.

[0015] Step 8: After the foundation pit construction is completed, the modular I-beam composite structure and sheet piles are removed and recycled in sequence using a hydraulic vibratory hammer. After disassembly, they are recycled and maintained for future use. The land in the recycled area can continue to be developed and utilized without the need for clearing obstacles.

[0016] The beneficial effects of this invention are:

[0017] This invention employs a modular I-beam composite structure. Compared to H-beams with similar cross-sections, the composite structure has a 24.3% larger moment of inertia while reducing its self-weight by 15.6%. Its bending resistance is superior to H-beams, yet the amount of steel used is significantly reduced, resulting in performance better than currently used foundation pit support steel. Prefabrication and assembly technology accelerates construction and reduces the long welding time required for conventionally used H-beams in foundation pit support. It is connected to Larssen sheet piles via interlocking joints to form a retaining and water-stopping structure.

[0018] This invention adopts a fully prefabricated steel structure, which is prefabricated in the factory and then assembled on site, making installation efficient and convenient. At the same time, its bending resistance and steel consumption are superior to traditional H-beam steel support structures. During construction, it does not affect the soil or groundwater, does not occupy land, and can be redeveloped. It is a green, low-carbon, and environmentally friendly structural system that solves the pollution of soil and groundwater caused by the traditional cement-soil mixing pile H-beam steel system. After removal, it does not affect land development and utilization. Its recycling feature also saves resources and achieves the goal of reducing carbon emissions, resulting in significant economic and social benefits. Attached Figure Description

[0019] Figure 1 This is a plan view of the modular I-beam assembly structure of the present invention;

[0020] Figure 2 This is a side view of the first section of the modular I-beam assembly structure of the present invention;

[0021] Figure 3 This is a side view of a standard section of the modular I-beam composite structure of the present invention;

[0022] Figure 4 This is a side view of the bottom section of the modular I-beam assembly structure of the present invention;

[0023] Figure 5 This is a side view of the connection node of the modular I-beam composite structure of the present invention;

[0024] Figure 6 This is a side view of the connection node between the forelimb and hindlimb of the modular I-beam structure of the present invention. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] like Figure 1 As shown, this invention is applied to foundation pit engineering. The modular I-beam composite structure 6 consists of front I-beam 1, rear I-beam 2, intermediate connecting truss 3 and locking joint 4. It is combined with Larssen sheet piles 5 to form a continuous steel wall, which serves the purpose of water stop and soil retention. The modular I-beam composite structure 6 can be spaced according to the stress requirements, and the module is 400mm.

[0027] like Figure 2As shown, the first section of the modular I-beam structure 6, viewed from the side, consists of a front I-beam 1, a rear I-beam 2, top and bottom truss plates 7, diagonal truss plates 8, and horizontal truss plates 9. The bottom 11 of the front I-beam and the bottom 12 of the rear I-beam are staggered to avoid the joints being on the same horizontal plane and affecting the stress. Simultaneously, bolt holes 10 for splicing are provided on the bottom truss plates 7, and flange bolt holes 13 and web bolt holes 14 are provided at the bottom 11 of the front I-beam and the bottom 12 of the rear I-beam. These bolt holes are connected by… Figure 5 , Figure 6 The nodes shown are used to connect the upper and lower sections of the structure to form a whole.

[0028] like Figure 3 As shown, the standard section of the modular I-beam structure 6, viewed from the side, consists of a front I-beam 1, a rear I-beam 2, top and bottom truss plates 7, diagonal truss plates 8, and horizontal truss plates 9. The tops and bottoms of the front I-beam 1 and the rear I-beam 2 are staggered to prevent the joints from being on the same horizontal plane and affecting the stress. Simultaneously, bolt holes 10 for splicing are provided in the truss plates 7, and flange bolt holes 13 and web bolt holes 14 are provided at the top and bottom of the front I-beams 11 and the top and bottom of the rear I-beams 12 of the standard section. These bolt holes are connected by... Figure 5 , Figure 6 The nodes shown are used to connect the upper and lower sections of the structure to form a whole.

[0029] like Figure 4 As shown, the bottom section of the modular I-beam structure 6, viewed from the side, consists of a front I-beam 1, a rear I-beam 2, top and bottom truss plates 7, diagonal truss plates 8, horizontal truss plates 9, and a "V"-shaped bottom end 15. The tops of the front I-beam 1 and the rear I-beam 2 are staggered to prevent the joints from being on the same horizontal plane and affecting the load-bearing capacity. Simultaneously, bolt holes 10 for splicing are provided in the truss plates 7, and flange bolt holes 13 and web bolt holes 14 are provided at the top of the front and rear I-beams of the bottom section. These bolt holes are connected by... Figure 5 , Figure 6 The nodes shown are used to connect the upper and lower sections of the structure to form a whole. The bottom is designed with a "V" shaped end for easy burial.

[0030] like Figure 5 As shown, the 6-joint connection node of the modular I-beam structure, viewed from the side, consists of the front I-beam 1, the rear I-beam 2, the top and bottom truss plates 7, the diagonal truss plates 8, the flange bolt holes 13, the web bolt holes 14, the two flange connecting plates 16, and the two top and bottom truss connecting plates 18.

[0031] like Figure 6As shown, the connection node of the modular I-beam structure 6, viewed from the single-limb connection point, consists of a front or rear I-beam 2, a diagonal truss plate 8, a horizontal truss plate 9, flange bolt holes 13, web bolt holes 14, two flange connecting plates 16, and two web connecting plates 17. At the same time, the staggered peaks 19 of the front or rear I-beam 2 at the flange are not on the same straight line to avoid poor stress distribution.

[0032] The construction steps of this invention are as follows:

[0033] Step 1: Based on the calculation results of the internal forces of the foundation pit, select a suitable I-beam composite structure. Its model and overall length should meet the requirements of the internal forces and stability of the foundation pit support. At the same time, the splice joint should be set at a position where the bending moment of the foundation pit is smaller.

[0034] Step 2: The I-beam composite structure is prefabricated in the factory and transported to the site. Trial assembly is carried out on site. The verticality and flatness after assembly are required to reach 1 / 1000. The bolt holes are aligned to ensure installation. The steel sheet piles are checked for interlocking and grease is applied.

[0035] Step 3: After accurate positioning, use machinery to hoist the bottom section of the I-beam composite structure to the designated position, adjust the plumb, and then use a vibratory hammer to vibrate and press down until it protrudes 1m above the ground. Then, assemble the middle section and the first section using connecting steel plates and high-strength bolts.

[0036] Step 4: After the assembly is completed, continue to vibrate and press down until the middle section and the first section are exposed 1m above the ground. The first section is exposed 200mm above the ground to facilitate later extraction and recycling, and at the same time to prevent surface water from entering the foundation pit.

[0037] Step 7: After one section of the I-beam composite structure is completed, Larssen sheet piles are driven on both sides. After hoisting them to the interlocking position of the I-beam composite structure, align them with the interlocking position, adjust the plumb, and then vibrate the vibratory hammer to press down to the designated position. Then, the next section of the I-beam composite structure is installed. This cycle is repeated until the entire foundation pit is completed. Corner sheet piles are used as the closing end at the corners to ensure the sealing of the entire foundation pit for water stoppage and soil retention.

[0038] Step 8: After the foundation pit construction is completed, the I-beam composite structure and sheet piles are removed and recycled in sequence using a hydraulic vibratory hammer. After dismantling, they are recycled and maintained for future use. The land in the recycled area can continue to be developed and utilized without the need for clearing obstacles.

Claims

1. A modular I-beam composite structure for foundation pit engineering, characterized in that: The structure includes a first section, intermediate standard sections, and a bottom section. These sections are connected to Larssen sheet piles via interlocking joints to form a retaining and water-stopping structure. After construction, the entire structure is recyclable and reusable, allowing continued use of the land in the construction area without the need for clearing. The modular I-beam structure consists of front I-beams, rear I-beams, an intermediate connecting truss, and interlocking joints. The interlocking joints are located on both sides of the front I-beams, with the openings facing opposite directions. The front and rear I-beams are made of I-beams ranging from No. 10 to No. 40, depending on the stress conditions of the foundation pit. A 20mm thick steel plate is welded together in the middle of the I-beam web to form a "Z"-shaped truss structure. The truss structure height increases sequentially from 500mm and 600mm to 1000mm according to the customized production module. The top and bottom steel plates of the "Z" shaped truss structure are 100mm wide, and the remaining steel plates are 50mm wide. The bottom splicing positions of the front and rear I-beams are staggered with unequal lengths to avoid the risk of breakage on the same horizontal plane. The first section is arranged with lengths of 6m and 9m respectively to ensure that the joint position is below the bottom of the foundation pit, so as to avoid the area of ​​the foundation pit with the greatest stress. Flange bolt holes and web bolt holes are arranged at the bottom of the front and rear limbs of the first section and on the truss connecting steel plates to facilitate connection with the next intermediate standard section.

2. The modular I-beam composite structure for foundation pit engineering according to claim 1, characterized in that: The intermediate standard section is 3m high. The front and rear I-beams are consistent with the first section, and the staggered position is consistent with the bottom of the first section. Flange bolts and web bolt holes are set in the front and rear I-beams and the web plate. The upper and lower sections are connected by flange connecting steel plates, web connecting steel plates, truss connecting steel plates and corresponding high-strength bolts. The width of the steel plates at the top and bottom of the truss is 100mm, and the width of the remaining steel plates is 50mm.

3. The modular I-beam composite structure for foundation pit engineering according to claim 2, characterized in that: The bottom section is 3m high. The front and rear I-beams are consistent with the middle standard section, and the staggered position is consistent with the bottom of the middle standard section. Flange bolts and web bolt holes are set in the front and rear I-beams. The width of the steel plates at the top and bottom of the truss is 100mm, and the width of the remaining steel plates is 50mm. At the same time, an "X" shaped cross is set at the end section to enhance the overall rigidity when the bottom is inserted into the soil. The bottom ends of the front and rear I-beams are tapered at 45 degrees to form "V" shaped bottom ends, which facilitates insertion into the soil and reduces resistance.

4. The modular I-beam composite structure for foundation pit engineering according to claim 1, characterized in that: The modular I-beam composite structure is equipped with Larssen sheet pile interlocking joints on both sides, which overlap with the Larssen sheet piles to form a continuous retaining and water-stopping steel wall. The spacing of the modular I-beam composite structure and the number of Larssen sheet piles are adjusted according to the stress requirements based on a 400mm module.

5. A construction method using the modular I-beam composite structure for foundation pit engineering as described in any one of claims 1-4 as foundation pit support, characterized in that, The construction steps are as follows: Step 1: Based on the internal force calculation results of the foundation pit, select a suitable modular I-beam composite structure. Its model and overall length should meet the requirements of the internal force and stability of the foundation pit support. At the same time, the splice joint should be set at a position where the bending moment of the foundation pit is smaller. Step 2: The modular I-beam composite structure is prefabricated in the factory and transported to the site. Trial assembly is carried out on site. The verticality and flatness after assembly are required to reach 1 / 1000. The bolt holes are aligned to ensure installation. The steel sheet piles are checked for lock joints and grease is applied. Step 3: After accurate positioning, use machinery to hoist the bottom section of the modular I-beam structure to the designated position. After adjusting the verticality, use a vibratory hammer to vibrate and press down until the bottom section is 1m above the ground. Then assemble the intermediate standard section and the first section. The assembly uses connecting steel plates and high-strength bolts. Step 4: After the assembly is completed, continue to vibrate and press down until the middle standard section and the first section are exposed 1m above the ground. The first section is exposed 200mm above the ground to facilitate later extraction and recycling, and at the same time to prevent surface water from entering the foundation pit. Step 5: After one section of the modular I-beam structure is completed, Larssen sheet piles are driven on both sides. After hoisting them to the interlocking position of the modular I-beam structure, they are aligned with the interlocking position, and after adjusting the plumb, the vibratory hammer is used to vibrate and press down. After reaching the designated position, the next section of the modular I-beam structure is installed. This process is repeated until the entire foundation pit is completed. Corner sheet piles are used as closing ends at the corners to ensure the sealing of the entire foundation pit for water stopping and soil retention. Step 6: After the foundation pit construction is completed, the modular I-beam composite structure and sheet piles are removed and recycled in sequence using a hydraulic vibratory hammer. After disassembly, they are recycled and maintained for future use. The land in the recycled area can continue to be developed and utilized without the need for clearing obstacles.

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