A method for filling a gap of a foundation trench of a fabricated underground continuous wall

Abstract

The application discloses an assembled underground continuous wall foundation trench gap filling method, which comprises the following steps: guiding wall foundation trench excavation; pre-buried grouting pipe; first underground continuous wall side foundation trench gap backfilling; next underground continuous wall assembling; next underground continuous wall side foundation trench gap backfilling; repeating the above steps until the backfilling of the foundation trench gap on the side of the second-to-last underground continuous wall is completed; hoisting the last underground continuous wall and placing it in the guiding wall foundation trench and assembling it with the previous underground continuous wall; backfilling sand and stones into the unfilled foundation trench gap until the gap is filled with sand and stones; and grouting the foundation trench gap through the pre-buried grouting pipe. The application adopts the method of stage-by-stage cyclic backfilling of the foundation trench gap, sand and stones are backfilled after the assembling of one underground continuous wall is completed, the method can timely provide support for the assembled underground continuous wall and the trench wall, ensures the wall piece assembling verticality and the sand and stone filling compactness, and can meet the requirements of the assembled construction of the super-deep underground continuous wall.

Description

Technical Field

[0001] This application relates to the field of retaining walls or similar walls constructed on-site using prefabricated components and concrete, including reinforced concrete, and specifically to a method for filling gaps in the foundation trench of a prefabricated underground continuous wall. Background Technology

[0002] For deep foundation pit excavation in saturated soft soil strata, diaphragm walls are one of the best retaining structures. However, traditional cast-in-place diaphragm walls often face problems such as bulging, exposed reinforcement, water leakage at joints, complex construction processes, and long construction periods. Due to the rapid development of prefabricated structures, the research and application of prefabricated diaphragm walls are increasing daily.

[0003] In existing prefabricated diaphragm wall technologies, the foundation trench gaps need to be filled with sand and gravel after the wall panels are fully assembled, or the sand and gravel needs to be filled in an area far from the wall panel assembly work surface to avoid the sand and gravel affecting the wall panel joint connection and the flatness of the wall bottom. As a result, the filling of the foundation trench gaps of prefabricated diaphragm walls can only be carried out after the wall panels are fully or mostly installed. The foundation trench gaps in the areas where the wall panels have been assembled in the early stage cannot be supported for a long time, which poses a risk of collapse of the weak strata. The assembled wall panels are subject to construction disturbances without support on both sides, making it difficult to control and maintain their sag, which also increases the difficulty of assembling subsequent wall panels.

[0004] As the application depth of prefabricated diaphragm walls increases, the shrinkage of the trench walls in soft strata increases, requiring larger trench gaps. This makes it more difficult to control aspects such as the verticality of ultra-deep wall panel assembly and the stability of the trench walls. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a method for filling the gaps in the foundation trench of a prefabricated diaphragm wall, which can provide timely support for the trench wall and the installed wall panels, ensuring the verticality of the wall panel assembly and the stability of the trench wall, and meeting the construction requirements of ultra-deep prefabricated diaphragm walls. The technical solution adopted is as follows:

[0006] A method for filling gaps in the foundation trench of a prefabricated underground continuous wall includes:

[0007] Step 1: Excavation of the guide wall foundation trench. After the guide wall foundation trench is formed, circulating mud is injected into the guide wall foundation trench.

[0008] Step 2, Pre-embed grouting pipes: Pre-embed grouting pipes on both sides of the guide wall foundation trench;

[0009] Step 3: Backfilling the gaps in the foundation trench on the side of the first diaphragm wall: After hoisting the first and second diaphragm walls in sequence, place them at one end of the guide wall foundation trench and assemble them. Set up a sand funnel at one end of the foundation trench gap and backfill sand and gravel into the foundation trench gap through the sand funnel. The sand and gravel will naturally collapse and accumulate in the foundation trench gap until the sand and gravel accumulate to the bottom of the second diaphragm wall near the sand funnel, and then stop backfilling sand and gravel.

[0010] Step 4: Assembling the next diaphragm wall: After hoisting the next diaphragm wall, place it in the guide wall trench and assemble it with the previous diaphragm wall.

[0011] Step 5: Backfilling the gaps in the foundation trench on the side of the next diaphragm wall: Set up a sand funnel at one end of the unfilled gap in the foundation trench, and backfill sand and gravel into the unfilled gap through the sand funnel. The sand and gravel will naturally collapse and accumulate in the gap until the sand and gravel accumulate to the bottom of the previous diaphragm wall near the side of the sand funnel, and then stop backfilling sand and gravel.

[0012] Step 6: Repeat steps 4 and 5 until the backfilling of the foundation trench gaps on the second-to-last underground continuous wall is completed;

[0013] Step 7: After hoisting the last diaphragm wall, place it in the guide wall trench and assemble it with the previous diaphragm wall. Use a sand funnel to backfill sand and gravel into the unfilled trench gaps until the trench gaps are full of sand and gravel, then stop backfilling sand and gravel.

[0014] Step 8: Grout the gaps in the foundation trench using pre-embedded grouting pipes.

[0015] One embodiment of the present invention uses the following technical solution to solve its technical problem: the particle size of the sand and gravel in steps 3, 5, and 7 is less than or equal to 1 / 5 of the width of the trench gap.

[0016] One embodiment of the present invention adopts the following technical solution to solve its technical problem: after the guide wall foundation trench is formed in step 2, geotextile is arranged on both sides of the trench wall, and then circulating mud is injected into the guide wall foundation trench.

[0017] One embodiment of the present invention adopts the following technical solution to solve its technical problem: In steps 2-8, after setting a sand and gravel detection device on the side of the bottom of the second diaphragm wall to the nth diaphragm wall near the sand funnel, the diaphragm wall is then lifted and placed in the guide wall trench.

[0018] One embodiment of the present invention provides a technical solution to solve its technical problem as follows: The sand and gravel detection device is provided on both sides of the diaphragm wall. The sand and gravel detection device includes a plumb bob, a traction rope, and a first baffle. The plumb bob is vertically arranged, and its tip is placed on the inner bottom wall of the trench gap. The first baffle is vertically installed at the upper end of the plumb bob and blocks the gap between the diaphragm wall and the inner wall of the guide wall trench. The first baffle has multiple holes, the diameter of which is smaller than the diameter of the sand and gravel. One end of the traction rope is connected to the upper end of the first baffle, and its upper end extends vertically upward and out of the guide wall trench.

[0019] One embodiment of the present invention adopts a technical solution to solve its technical problem as follows: it further includes two second baffles, which are vertically installed on the first baffle and distributed intersecting with it.

[0020] The beneficial effects of this invention are:

[0021] (1) This application adopts a phased cyclic backfilling method for the trench gaps. After each diaphragm wall is assembled, sand and gravel are backfilled, and the construction is carried out in a cyclical manner until the diaphragm wall is assembled. This allows the sand and gravel to collapse to the bottom of the diaphragm wall, which can provide timely support for the assembled diaphragm wall and trench wall, ensure the verticality of the wall panel assembly, ensure the dense filling of sand and gravel, and meet the requirements for the assembly construction of ultra-deep diaphragm walls.

[0022] (2) By setting up geotextile, the impact and disturbance of falling sand and gravel on the trench wall can be prevented, thus ensuring the stability of the trench wall of the guide wall foundation.

[0023] (3) The particle size of the sand and gravel shall not exceed 1 / 5 of the width of the trench gap in order to avoid the trench gap from being blocked. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 A flowchart illustrating the method for filling gaps in the foundation trench of a prefabricated underground continuous wall.

[0026] Figure 2 This is a schematic diagram of the foundation trench after backfilling on the side of the first diaphragm wall;

[0027] Figure 3 This is a schematic diagram of the backfilling of the foundation trench gaps on the side of the second diaphragm wall;

[0028] Figure 4 This is a schematic diagram of the backfilling of the foundation trench gaps on the side of the third diaphragm wall;

[0029] Figure 5 This is a schematic diagram of the backfilling of the foundation trench gaps on the side of the (n-1)th diaphragm wall.

[0030] Figure 6 This is a schematic diagram of the sand and gravel testing device of this application;

[0031] Figure 7 This is a top view of the guide wall foundation trench. Detailed Implementation

[0032] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0033] In the description of this invention, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0034] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0035] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to a fixed connection, a detachable connection, or an integrally formed connection; they can refer to a mechanical connection; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0036] See attached document Figure 1 The present invention illustrates an embodiment of the prefabricated diaphragm wall foundation trench gap filling method described in this application. The prefabricated diaphragm wall comprises n diaphragm walls, where n is a positive integer. The diaphragm wall foundation trench gap filling method specifically includes:

[0037] Step 1: Excavation of guide wall trench 1. After the guide wall trench 1 is formed, geotextile is placed on both sides of the trench wall 1, and circulating mud is injected into the guide wall trench 1.

[0038] Step 2, Pre-embed grouting pipe 2: Pre-embed grouting pipe 2 on both sides of the guide wall foundation trench 1;

[0039] Step 3, refer to the appendix Figure 2 As shown, the backfilling of the foundation trench gap on the side of the first diaphragm wall 3 is as follows: The first diaphragm wall 3 and the second diaphragm wall 4 are lifted in sequence and placed at one end of the guide wall foundation trench 1 and assembled. A sand funnel 5 is set at one end of the foundation trench gap. Sand and gravel 6 are backfilled into the foundation trench gap through the sand funnel 5. The particle size of the sand and gravel 6 is less than or equal to 1 / 5 of the width of the foundation trench gap. The sand and gravel 6 naturally collapses and accumulates in the circulating mud in the foundation trench gap until the sand and gravel 6 accumulates to the bottom of the second diaphragm wall 4 near the side of the sand funnel 5, and the backfilling of sand and gravel 6 is stopped.

[0040] Assembly of the third diaphragm wall: After hoisting the third diaphragm wall 9, place it in the guide wall trench 1 and assemble it with the second diaphragm wall 4.

[0041] Backfilling of the foundation trench joints on sides of the third diaphragm wall (section 9): The foundation trench joints refer to the gaps formed by the enclosure of the foundation trench 1 between the first, second, and third diaphragm walls and the guide wall. The gaps filled with sand and gravel are the backfilled foundation trench joints, while the unfilled portions are the un-backfilled foundation trench joints. (See attached diagram.) Figure 3 As shown, a sand funnel 5 is set at one end of the unfilled foundation trench gap. Sand and gravel 6 are backfilled into the unfilled foundation trench gap through the sand funnel 5. The sand and gravel 6 naturally collapse and accumulate in the foundation trench gap until the sand and gravel 6 accumulates to the bottom of the second underground continuous wall 4 near the side of the sand funnel 5, and then the backfilling of sand and gravel 6 is stopped.

[0042] Assembly of the fourth diaphragm wall 10: After being lifted, the fourth diaphragm wall 10 is placed in the guide wall trench 1 and assembled with the third diaphragm wall 9.

[0043] Backfilling of the foundation trench joints on the 10th side of the fourth diaphragm wall: Refer to Appendix Figure 4 As shown, a sand funnel 5 is set at one end of the unfilled foundation trench gap. Sand and gravel 6 are backfilled into the unfilled foundation trench gap through the sand funnel 5. The sand and gravel 6 naturally collapse and accumulate in the foundation trench gap until the sand and gravel 6 accumulates to the bottom of the third underground continuous wall 9 near the side of the sand funnel 5, and then the backfilling of sand and gravel 6 is stopped.

[0044] Step 4: Assembly of the next diaphragm wall: After hoisting the next diaphragm wall, place it in the guide wall trench 1 and assemble it with the previous diaphragm wall.

[0045] Step 5: Backfilling the gaps in the foundation trench on the side of the next diaphragm wall: After the next diaphragm wall is lifted, it is placed in the guide wall trench 1 and assembled with the previous diaphragm wall. A sand funnel 5 is set at one end of the unfilled gap in the foundation trench. Sand and gravel 6 are backfilled into the unfilled gap through the sand funnel 5. The sand and gravel 6 naturally collapses and accumulates in the gap until the sand and gravel 6 accumulates to the bottom of the previous diaphragm wall near the side of the sand funnel 5, at which point the backfilling of sand and gravel 6 is stopped.

[0046] Step 6: Repeat steps 4 and 5 until the backfilling of the foundation trench joints on the four sides of the (n-1)th diaphragm wall is completed. Figure 5 As shown,

[0047] Step 7: After lifting the nth diaphragm wall 7, place it in the guide wall trench 1 and assemble it with the (n-1)th diaphragm wall. Backfill the unfilled trench gaps with sand and gravel 6 through the sand funnel 5 until the trench gaps are filled with sand and gravel 6, then stop backfilling with sand and gravel 6.

[0048] Step 8: Grout the gaps in the foundation trench through the pre-embedded grouting pipe 2.

[0049] After each diaphragm wall is lifted and placed in the guide wall trench 1, a sand and gravel detection device 8 is installed on the side of the bottom of the n diaphragm walls near the sand funnel 5 in the trench. When the sand and gravel detection device 8 detects sand and gravel, the backfilling of sand and gravel 6 is stopped, the sand and gravel detection device 8 is removed, and the lifting and placement of the next diaphragm wall continues.

[0050] In this embodiment, the sand and gravel detection device 8 is provided on both sides of the underground continuous wall 4. The sand and gravel detection device 8 includes a plumb bob cone 81, a traction rope 82, and a first baffle 83. The plumb bob cone 81 is vertically arranged, and the tip of the plumb bob cone 81 is used to place on the inner bottom wall of the foundation trench gap. The first baffle 83 is vertically installed on the upper end of the plumb bob cone 81 and blocks the gap between the underground continuous wall and the inner wall of the guide wall foundation trench 1. The first baffle 83 is provided with a plurality of holes 84, the diameter of which is smaller than the diameter of the sand and gravel. One end of the traction rope 82 is connected to the upper end of the first baffle 83, and its upper end extends vertically upward and out of the guide wall foundation trench 1.

[0051] It also includes a second baffle 85, which is vertically mounted on the first baffle 83 and distributed intersecting with it.

[0052] The first baffle 83 and the second baffle 85 are steel plates, and the traction rope 82 is a steel rope. The first baffle 83 and the second baffle 85 are arranged in a cross shape and welded to a plumb bob cone. The upper part is tied to the steel wire rope. The first baffle 83 is set along the width direction of the guide wall trench 1, and the length of the first baffle 83 is slightly smaller than the width of the trench, so as to ensure that the first baffle 83 can be smoothly lowered to the bottom of the trench and block the gap between the underground continuous wall and the inner wall of the guide wall trench 1. The diameter of the hole is slightly smaller than the minimum backfill gravel particle size, and the number of holes is determined according to the actual situation of the project.

[0053] See attached document Figure 7 As shown, the sand and gravel detection device 8 is lowered from the ground to the bottom of the trench via a traction rope 82. A plumb bob cone 81 controls the sag to ensure accurate landing. The first baffle 83 and the second baffle 85 ensure that undulating mud at the bottom of the trench can pass through the holes, while the backfilled gravel cannot, thus reducing the disturbance of the mud to the device and providing support and sensing for the backfilled gravel. During sand and gravel backfilling, the backfilling speed should be controlled to reduce the disturbance of mud undulations to the first baffle 83 and the second baffle 85. When the sand and gravel are backfilled to the first baffle 83 and the second baffle 85, the gravel exerts pressure and impact on the first baffle 83 and the second baffle 85. This disturbance effect is transmitted to the ground via the traction rope 82 and significantly affects the sag of the traction rope 82. At this point, it is determined that the sand and gravel backfilling is in place, and the current sand and gravel backfilling process is immediately stopped.

[0054] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications and substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for filling gaps in the foundation trench of a prefabricated underground continuous wall, characterized in that, include: Step 1: Excavation of the guide wall trench (1). After the guide wall trench (1) is formed, circulating mud is injected into the guide wall trench (1). Step 2, Pre-embed grouting pipes (2): Pre-embed grouting pipes (2) on both sides of the guide wall foundation trench (1); Step 3: Backfilling the gaps in the foundation trench on the side of the first diaphragm wall (3): After the first diaphragm wall (3) and the second diaphragm wall (4) are lifted in sequence, they are placed at one end of the guide wall foundation trench (1) and assembled. A sand funnel (5) is set at one end of the foundation trench gap. Sand and gravel (6) are backfilled into the foundation trench gap through the sand funnel (5). The sand and gravel (6) collapses and accumulates naturally in the foundation trench gap until the sand and gravel (6) accumulates to the bottom of the second diaphragm wall (4) near the side of the sand funnel (5), and the backfilling of sand and gravel (6) is stopped. Step 4: Assembly of the next diaphragm wall: After hoisting the next diaphragm wall, place it in the guide wall trench (1) and assemble it with the previous diaphragm wall. Step 5: Backfilling the foundation trench gaps on the side of the next diaphragm wall: Set up a sand funnel (5) at one end of the unfilled foundation trench gap, and backfill sand and gravel (6) into the unfilled foundation trench gap through the sand funnel (5). The sand and gravel (6) will naturally collapse and accumulate in the foundation trench gap until the sand and gravel (6) accumulate to the bottom of the previous diaphragm wall on the side close to the sand funnel (5), and then stop backfilling the sand and gravel (6). Step 6: Repeat steps 4 and 5 until the backfilling of the foundation trench gaps on the penultimate side of the diaphragm wall (4) is completed; Step 7: After lifting the last diaphragm wall (7), place it in the guide wall trench (1) and assemble it with the previous diaphragm wall. Use a sand funnel (5) to backfill sand and gravel (6) into the unfilled trench gaps until the trench gaps are filled with sand and gravel (6), then stop backfilling sand and gravel (6). Step 8: Grout the gaps in the foundation trench using the pre-embedded grouting pipe (2).

2. The method for filling gaps in the foundation trench of a prefabricated underground continuous wall according to claim 1, characterized in that, In steps 3, 5, and 7, the particle size of the sand and gravel (6) is less than or equal to 1 / 5 of the width of the trench gap.

3. The method for filling gaps in the foundation trench of a prefabricated underground continuous wall according to claim 1, characterized in that, After the guide wall trench (1) is formed in step 2, geotextile is placed on both sides of the trench wall (1) and then circulating mud is injected into the guide wall trench (1).

4. The method for filling gaps in the foundation trench of a prefabricated underground continuous wall according to claim 1, characterized in that, In steps 2-8, after setting up a sand and gravel detection device (8) on the side of the bottom of the second diaphragm wall (4) to the penultimate diaphragm wall near the sand funnel (5), the next diaphragm wall is lifted and placed in the guide wall trench (1).

5. The method for filling gaps in the foundation trench of a prefabricated underground continuous wall according to claim 4, characterized in that, The sand and gravel detection device (8) is provided on both sides of the underground continuous wall (4). The sand and gravel detection device (8) includes a plumb cone (81), a traction rope (82) and a first baffle (83). The plumb cone (81) is set vertically, and the tip of the plumb cone (81) is used to place on the inner bottom wall of the foundation trench gap. The first baffle (83) is installed vertically at the upper end of the plumb cone (81) and blocks the gap between the underground continuous wall and the inner wall of the guide wall foundation trench (1). The first baffle (83) is provided with multiple holes (84). The diameter of the holes (84) is smaller than the diameter of the sand and gravel. One end of the traction rope (82) is connected to the upper end of the first baffle (83), and its upper end extends vertically upward and out of the guide wall foundation trench (1).

6. The method for filling gaps in the foundation trench of a prefabricated underground continuous wall according to claim 5, characterized in that, It also includes a second baffle (85), which is vertically mounted on the first baffle (83) and distributed intersecting with it.

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