Construction method of folded line type diaphragm wall segment joint

Abstract

The application discloses a construction method for a folded-line type diaphragm wall segment joint, and relates to the technical field of underground continuous wall construction processes. The method comprises the following steps: after a first-stage groove is formed, a removable placeholder pipe is arranged at one end of the first-stage groove and a second-stage groove; a millable pipe is embedded in one end of a first-stage reinforcement cage opposite to the placeholder pipe, and the first-stage reinforcement cage is arranged in the first-stage groove; concrete of the first-stage groove is poured, and after the concrete in the first-stage groove reaches a preset strength, the placeholder pipe is pulled out; a second-stage groove is formed, and the millable pipe and the concrete at the position of the placeholder pipe are milled off. The application can effectively reduce the amount of concrete used when the first-stage groove is poured, effectively reduce the amount of concrete milling when the second-stage groove is formed, effectively reduce the risk of pulling out the placeholder pipe and the requirement for a pipe pulling machine, and meet the demand for building a diaphragm wall well in an area lacking in human resources.

Description

A construction method for a zigzag-shaped diaphragm wall segment joint Technical Field

[0001] This invention relates to the field of underground diaphragm wall construction technology, specifically to a method for constructing joints in a zigzag-shaped diaphragm wall segment. Background Technology

[0002] A diaphragm wall, or diaphragm wall for short, is a continuous reinforced concrete wall constructed underground as a water-cutting, seepage-prevention, load-bearing, and water-retaining structure. A certain diaphragm wall cofferdam project, located in an area with scarce human resources, had high requirements, a tight schedule, and a heavy workload. Traditional construction methods for concrete cut-off wall joints include drilling, double reverse arc, single reverse arc, and pipe connection methods. Among these, drilling is suitable for low-strength concrete cut-off wall construction, while the commonly used jointing techniques are the reverse arc method (including single and double reverse arc) and the pipe connection method. Specifically:

[0003] The "drilling method" involves drilling joints (joint holes) at both ends of the first-stage wall section after the first-stage trench concrete is poured, and then drilling the second-stage trench, ultimately forming a semi-circular joint between the first and second-stage wall sections. This method is suitable for drilling with impact drills and for wall materials made of low-strength concrete. However, for deep, high-grade concrete anti-seepage walls, the "drilling method" is less effective, more costly, and has difficulty guaranteeing quality.

[0004] The "single reverse arc" process involves first constructing the main holes (i.e., single-arc guide holes) at both ends using an impact reverse circulation drilling rig after the adjacent first-phase trench is poured. After the guide holes pass the final hole acceptance, the holes are enlarged using a double reverse arc drill bit. While enlarging the holes, the stone debris in the main holes is extracted using a reverse circulation method until the holes are completed. Then, the mud skin and part of the concrete around the semi-circular arc of the concrete at the end hole of the first-phase trench are chiseled out to form a single arc joint surface.

[0005] The "double reverse arc" process leaves a joint hole between two adjacent first-stage trenches as a second-stage trench. After the first-stage trench concrete is poured, a circular joint hole is first drilled, then the hole is enlarged with a double reverse arc drill bit, and then the mud residue remaining on the first-stage wall section is removed and cleaned with a hydraulic tensionable double reverse arc drill bit. Finally, the wall is poured.

[0006] The "joint pipe" process involves placing specialized joint pipes at both ends of the trench before pouring the first-stage trench concrete. Concrete is then poured, and after initial setting, the joint pipes are pulled out at a certain speed. This creates a smooth semi-cylindrical surface at both ends of the first-stage wall section and two guide holes to facilitate the construction of the second-stage trench. After the second-stage trench construction is completed, a joint surface is formed here. However, this process requires high-quality pouring of the second-stage trench concrete to prevent water seepage at the joint.

[0007] However, the depth of diaphragm wall cofferdams is relatively deep (the maximum depth exceeds 100 meters), resulting in low trenching efficiency, significant equipment limitations, extreme difficulty in ensuring trench verticality, high construction technology requirements, and high professional skills requirements for construction personnel. Furthermore, the labor costs are high in areas with a shortage of human resources. Therefore, existing construction methods cannot meet the needs of this project. Summary of the Invention

[0008] To address the technical problem that existing diaphragm wall construction techniques are insufficient to meet the requirements of ultra-deep diaphragm wall cofferdam construction in areas with limited human resources, this invention provides a method for constructing zigzag-shaped diaphragm wall segment joints. This method not only meets the requirements of ultra-deep diaphragm wall cofferdam construction in areas with limited human resources, but also ensures the inclination rate of the trench, shortens the construction period, and saves costs.

[0009] This invention is achieved through the following technical solution:

[0010] This invention provides a construction method for a zigzag-shaped diaphragm wall segment joint, comprising the following steps:

[0011] S10. After the first-stage trench is formed, a pull-out occupant pipe is provided at the end where the first-stage trench connects to the second-stage trench.

[0012] S20. A millable pipe fitting is embedded in one end of the first-phase steel cage directly opposite the occupant pipe fitting, and the first-phase steel cage is placed in the first-phase trench.

[0013] S30. Pour concrete into the first-stage trench, and after the concrete in the first-stage trench reaches the preset strength, pull out the occupant pipe.

[0014] S40. Excavate the second-stage trench and mill away the concrete from the millable pipe fitting and the occupant pipe fitting.

[0015] The present invention provides a method for constructing a zigzag-type diaphragm wall segment joint. First, after the first-stage trench is formed, a removable occupant is installed at one end connecting the first-stage and second-stage trenches. A millable component is embedded in the end of the first-stage reinforcing cage directly opposite the occupant. The first-stage reinforcing cage is then placed inside the first-stage trench, and concrete is poured into the first-stage trench. The occupant and millable component occupy the cavity at the intersection of the first and second-stage trenches, effectively reducing the amount of concrete used during the first-stage trench pouring and the amount of concrete milling required for the second-stage trench, thereby shortening the construction period. Then, after the concrete in the first-stage trench reaches the preset strength, the occupant is removed.

[0016] In this process, since the spacer fitting and the millable fitting share the cavity of the milled section where the first and second phase trenches intersect, the spacer fitting has a small cross-sectional size. Compared with the "joint pipe" process, the contact area between the spacer fitting and the concrete in the first phase trench is smaller. Therefore, the friction is relatively smaller when pulling out the spacer fitting, which can effectively reduce the risk of pulling out the spacer fitting and the requirements for the pipe pulling machine. This reduces the cost of equipment and personnel, and meets the needs of building diaphragm wall cofferdams in areas with a lack of human resources.

[0017] After removing the occupant pipe fitting, the second-stage trench is excavated, and the concrete of the millable pipe fitting and the occupant pipe fitting is milled away. At this time, the amount of concrete milled is small, and by milling the concrete of the first-stage trench, the verticality of the diaphragm wall section can be effectively improved, ensuring the inclination of the trench hole, and effectively reducing the time for repairing the hole due to the low verticality of the grab bucket trench, further shortening the construction period.

[0018] In summary, the method for constructing zigzag-shaped diaphragm wall segment joints provided by this invention can meet the construction requirements of ultra-deep diaphragm wall cofferdams in areas with limited human resources, while ensuring the inclination of the trench, shortening the construction period, and saving costs.

[0019] In an optional embodiment, the cross-sectional dimensions of the occupier are adapted to the large end cross-section of the milled portion where the first-stage trench and the second-stage trench intersect, so as to ensure that the occupier can occupy the cavity of the milled portion where the first-stage trench and the second-stage trench intersect as much as possible, further reducing the amount of concrete used when pouring the first-stage trench and further reducing the amount of concrete milling when forming the second-stage trench.

[0020] In an optional embodiment, the cross-sectional dimensions of the millable fitting are adapted to the small end cross-section of the milled portion where the first-stage trench and the second-stage trench intersect, ensuring that the occupier fitting can occupy the cavity of the milled portion where the first-stage trench and the second-stage trench intersect as much as possible, further reducing the amount of concrete used during the pouring of the first-stage trench and further reducing the amount of concrete milling required for the formation of the second-stage trench.

[0021] In an alternative embodiment, the millable fitting is a PVC pipe, so that the millable fitting has sufficient millability and can also reduce the cost of using the millable fitting.

[0022] In an alternative embodiment, the millable pipe is tied inside the primary reinforcement cage to facilitate the placement of the millable pipe.

[0023] In an optional implementation, both the first-stage trench and the second-stage trench are formed by a process of first grasping and then cutting. The trenching machine has the advantages of intelligent correction, fast work efficiency, high trenching accuracy, low noise, and environmentally friendly construction, which meets the needs of ultra-deep diaphragm wall cofferdam construction.

[0024] In an optional implementation, the post-cutting process of the gripper involves first gripping the cover layer with a gripper head and then milling the groove with a milling machine.

[0025] In an optional embodiment, the occupant is pulled out before the concrete in the primary trench reaches its initial setting state, so as to facilitate the removal of the occupant and avoid the impact of the removal of the occupant on the concrete in the primary trench.

[0026] In an optional embodiment, the spacer fitting is a steel pipe, so that the spacer fitting has sufficient structural strength to ensure that the lowering and pulling of the spacer fitting can be carried out smoothly.

[0027] In an optional implementation, the method further includes the step of: S50, pouring concrete into the second-stage trench to form a complete zigzag diaphragm wall segment.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] 1. The construction method for the zigzag-type diaphragm wall segment joint provided by the present invention involves first, after the first-stage trench is formed, installing a pull-out occupier at one end where the first-stage trench connects to the second-stage trench, and then embedding a millable pipe at one end of the first-stage reinforcing cage directly opposite the occupier. The first-stage reinforcing cage is then placed in the first-stage trench, and concrete is poured into the first-stage trench. By using the occupier and the millable pipe to occupy the cavity of the milled portion where the first-stage trench and the second-stage trench intersect, the amount of concrete used during the first-stage trench pouring is effectively reduced, and the amount of concrete milling during the second-stage trench formation is effectively reduced, thereby shortening the construction period.

[0030] 2. The method for constructing a zigzag-shaped diaphragm wall segment joint provided by this invention involves pulling out the occupier after the concrete in the first-stage trench reaches the preset strength. Since the occupier and the millable pipe share the cavity of the milled portion where the first-stage trench and the second-stage trench intersect, the cross-sectional size of the occupier is small. Compared with the "joint pipe" process, the contact area between the occupier and the concrete in the first-stage trench is smaller. Therefore, the friction is relatively smaller when pulling out the occupier, which can effectively reduce the risk of pulling out the occupier and the requirements for the pipe pulling machine, thereby reducing the cost of equipment and personnel, and meeting the needs of constructing diaphragm wall cofferdams in areas with a lack of human resources.

[0031] 3. The construction method for the zigzag-type diaphragm wall segment joint provided by the present invention involves excavating a second-stage trench after removing the occupant pipe, and milling away the concrete of the millable pipe and the occupant pipe. At this time, the amount of concrete milling is small, and by milling the concrete of the first-stage trench, the verticality of the diaphragm wall segment can be effectively improved, ensuring the inclination of the trench hole, and effectively reducing the time for hole repair due to low verticality of the grab bucket trench, further shortening the construction period. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] In the attached diagram:

[0034] Figure 1 is a schematic flowchart of the construction method for the joint of the zigzag-type diaphragm wall segment according to an embodiment of the present invention;

[0035] Figure 2 is a structural schematic diagram of the construction process of the zigzag-type diaphragm wall segment joint in an embodiment of the present invention.

[0036] The attached diagram shows the markings and corresponding component names:

[0037] 1-Phase I trench, 2-Phase II trench, 3-Occupant fitting, 4-Millable fitting. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0039] In the description of the embodiments of this application, the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships conventionally understood by those skilled in the art. These are used only for the convenience of describing this application and for simplification, and therefore should not be construed as limiting this application. Furthermore, the related terms should be interpreted broadly. Those skilled in the art can understand the specific meaning of the above terms in the invention according to the specific circumstances.

[0040] This underground diaphragm wall cofferdam project is located in an area with limited human resources, and faces high requirements, a tight schedule, and heavy workload. The cofferdam has a decagonal structure, with the long side designated as the first-stage trench (6.4m long) and the short side as the second-stage trench (2.8m long), resulting in a maximum milling length of 46m. The maximum depth of the diaphragm wall reaches 105.5m. Traditional concrete cut-off wall joint construction methods suffer from low trenching efficiency, limited equipment, difficulty in ensuring trench verticality, high technical requirements, and high skill demands on construction personnel. Furthermore, they incur high labor costs in areas with limited human resources, making them unsuitable for this project. Therefore, the applicant has proposed the following construction method:

[0041] Example

[0042] Referring to Figure 1, this embodiment provides a construction method for a zigzag-shaped diaphragm wall segment joint, including:

[0043] S10. After the first-stage trench 1 is formed, a pull-out occupant pipe 3 is provided at the end where the first-stage trench 1 connects to the second-stage trench 2.

[0044] Specifically, for trench 1 in Phase I, a "grab-then-mill" process is used. That is, the overburden layer is first grasped by a grabber, and then the trench is milled by a milling machine. The milling machine has the advantages of intelligent correction, fast efficiency, high trenching accuracy, low noise, and environmentally friendly construction, which meets the needs of ultra-deep diaphragm wall cofferdam construction.

[0045] Referring to Figure 2, it can be understood that the cross-sectional dimensions of the spacer fitting 3 are adapted to the large end cross-section of the milled portion where the first-stage trench 1 and the second-stage trench 2 intersect. This ensures that the spacer fitting 3 can occupy the cavity of the milled portion where the first-stage trench 1 and the second-stage trench 2 intersect as much as possible, further reducing the amount of concrete used during the pouring of the first-stage trench 1 and further reducing the amount of concrete milling required for the formation of the second-stage trench 2. That is, the actual size of the spacer fitting 3 is determined based on the size of the milled portion where the first-stage trench 1 and the second-stage trench 2 intersect, and it is generally advisable that the spacer fitting 3 is tangent to the side walls of the large end of the milled portion where the first-stage trench 1 and the second-stage trench 2 intersect.

[0046] The spacer fitting 3 is made of steel pipe to ensure that the spacer fitting has sufficient structural strength and that the lowering and pulling of the spacer fitting 3 can be carried out smoothly.

[0047] S20. A millable pipe fitting 4 is embedded in one end of the first-stage steel cage directly opposite the occupant pipe fitting 3, and the first-stage steel cage is placed in the first-stage groove 1.

[0048] Referring to Figure 2, specifically, the cross-sectional dimensions of the millable pipe fitting 4 are adapted to the small-end cross-section of the milled portion where the first-stage trench 1 and the second-stage trench 2 intersect. This ensures that the occupier fitting 3 can occupy the cavity of the milled portion where the first-stage trench 1 and the second-stage trench 2 intersect as much as possible, further reducing the amount of concrete used during the pouring of the first-stage trench 1 and further reducing the amount of concrete milling required for the formation of the second-stage trench 2. In this embodiment, it is preferable that the side walls of the small end of the milled portion where the millable pipe fitting 4 intersects with the first-stage trench 1 and the second-stage trench 2 are tangent.

[0049] In this embodiment, the millable pipe 4 is a PVC pipe, so that the millable pipe 4 has sufficient millability and can also reduce the cost of using the millable pipe 4.

[0050] It is understandable that the millable pipe 4 is tied inside the first-phase steel cage to facilitate the placement of the millable pipe 4.

[0051] S30. Pour concrete into the first-stage trench 1, and after the concrete in the first-stage trench 1 reaches the preset strength, pull out the occupant pipe 3.

[0052] It should be understood that the occupant pipe 3 is pulled out before the concrete in the first-stage trench 1 reaches its initial setting state, so as to facilitate the removal of the occupant pipe 3 and avoid the impact of removing the occupant pipe 3 on the concrete in the first-stage trench 1. Given the engineering environment in which this application is made, the initial setting time of the concrete used by the applicant is 4-6 hours. Therefore, the occupant pipe is typically removed 3.5-5.5 hours after the concrete is poured.

[0053] S40. Excavate the second-stage trench 2 and mill away the concrete from the millable pipe fitting 4 and the occupier pipe fitting 3.

[0054] Similarly, for the trenching of Phase II trench 2, a "grab-then-mill" process is used. That is, the overburden layer is first grasped by a grabber, and then the trench is milled by a milling machine. The milling machine has the advantages of intelligent correction, fast efficiency, high trenching accuracy, low noise, and environmentally friendly construction, which meets the needs of ultra-deep diaphragm wall cofferdam construction.

[0055] S50. Pour concrete into the second-stage trench 2 to form a complete zigzag diaphragm wall segment.

[0056] In summary, the construction method for the zigzag diaphragm wall segment joint provided in this embodiment involves first, after the first-stage trench 1 is formed, a pullable occupant pipe fitting 3 is installed at the end where the first-stage trench 1 connects to the second-stage trench 2. A millable pipe fitting 4 is embedded in the end of the first-stage reinforcing cage directly opposite the occupant pipe fitting. The first-stage reinforcing cage is then placed in the first-stage trench 1, and concrete is poured into the first-stage trench 1. The occupant pipe fitting 3 and the millable pipe fitting 4 occupy the cavity of the milled portion where the first-stage trench 1 and the second-stage trench 2 intersect, effectively reducing the amount of concrete used during the pouring of the first-stage trench 1 and effectively reducing the amount of concrete milling during the formation of the second-stage trench 2, thereby shortening the construction period. Then, after the concrete in the first-stage trench 1 reaches the preset strength, the occupant pipe fitting 3 is pulled out.

[0057] Since the occupier 3 and the millable pipe 4 share the cavity of the milled part where the first-stage trench 1 and the second-stage trench 2 intersect, the occupier 3 has a small cross-sectional size. Compared with the "joint pipe" process, the contact area between the occupier 3 and the concrete of the first-stage trench 1 is relatively small. Therefore, the friction is relatively small when pulling out the occupier 3, which can effectively reduce the risk of pulling out the occupier 3 and the requirements for the pipe pulling machine equipment, thereby reducing the cost of equipment and personnel, and meeting the needs of building diaphragm wall cofferdams in areas with a lack of human resources.

[0058] After removing the occupant pipe 3, the second-stage trench 2 is excavated, and the concrete of the millable pipe 4 and the occupant pipe 3 is milled away. At this time, the amount of concrete milled is small, and by milling the concrete of the first-stage trench 1, the verticality of the diaphragm wall section can be effectively improved, the inclination of the trench hole can be ensured, and the time for repairing the hole due to the low verticality of the grab bucket trench can be effectively reduced, further shortening the construction period.

[0059] Actual construction verification shows that the zigzag diaphragm wall segment joint construction method provided in this embodiment reduces the construction time by ≥25% compared to traditional construction methods, thereby saving 1 / 6 to 1 / 4 of the concrete material.

[0060] In summary, the zigzag-shaped diaphragm wall segment joint construction method provided in this embodiment can meet the construction requirements of ultra-deep diaphragm wall cofferdams in areas with limited human resources, while ensuring the inclination of the trench, shortening the construction period, and saving costs.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A construction method for a zigzag-shaped diaphragm wall segment joint, characterized in that, Includes the following steps: S10. After the first-stage trench (1) is formed, a pull-out occupant pipe fitting (3) is provided at the end where the first-stage trench (1) and the second-stage trench (2) are connected. The cross-sectional dimensions of the occupant pipe fitting (3) are adapted to the large end cross-section of the milled portion where the first-stage trench (1) and the second-stage trench (2) intersect. S20. A millable pipe fitting (4) is embedded in the end of the first-stage reinforcing cage facing the occupant pipe fitting (3), and the first-stage reinforcing cage is placed in the first-stage trench (1). The cross-sectional dimensions of the pipe fitting (4) are adapted to the small end cross-section of the milled portion where the first-stage trench (1) and the second-stage trench (2) intersect; S30, pour concrete into the first-stage trench (1), and after the concrete in the first-stage trench (1) reaches the preset strength, pull out the occupier (3); S40, dig the second-stage trench (2), and mill away the concrete of the millable pipe fitting (4) and the occupier (3); S50, pour concrete into the second-stage trench (2).

2. The construction method for the joint of the zigzag-shaped diaphragm wall segment according to claim 1, characterized in that, The millable pipe fitting (4) is a PVC pipe.

3. The construction method for the joint of the zigzag-shaped diaphragm wall segment according to claim 2, characterized in that, The millable pipe (4) is tied inside the first-phase steel cage.

4. The construction method for the joint of the zigzag-shaped diaphragm wall segment according to claim 1, characterized in that, Both the first-stage groove (1) and the second-stage groove (2) are formed by a process of first grasping and then cutting.

5. The construction method for the joint of the zigzag-shaped diaphragm wall segment according to claim 4, characterized in that, The process of first grabbing and then milling involves first grabbing the cover layer with a gripper and then milling the groove with a milling machine.

6. The construction method for the joint of the zigzag-shaped diaphragm wall segment according to claim 1, characterized in that, The occupant pipe (3) is pulled out before the concrete in the first-stage trench (1) reaches the initial setting state.

7. The construction method for the joint of the zigzag-shaped diaphragm wall segment according to claim 1, characterized in that, The occupier (3) is a steel pipe.

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