Construction method for preventing trench wall collapse of underground continuous wall in soft soil area

Abstract

The application discloses a kind of soft soil area underground continuous wall anti-slot wall collapse construction method, comprising the following steps: S1, guide wall construction;S2, continuous wall slotting construction;S3, continuous wall pouring;S4, foundation pit excavation.Step S2 in anti-collapse component includes the fixed track located in the both sides of guide wall, and the telescopic vertical rod between two fixed tracks, telescopic vertical rod right side is fixed with telescopic guide pipe, and the bottom of telescopic guide pipe is equipped with telescopic elbow pipe.The method of the application focuses on a series of steps before foundation pit excavation is optimized and adjusted, for the problem that soft soil area is prone to collapse, the stability during subsequent foundation pit excavation is guaranteed, especially for the anti-collapse of slot wall during continuous wall slotting construction is optimized in parameter and related structure, greatly reduces the event occurrence probability of slot wall collapse during continuous wall slotting excavation in soft soil area.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, specifically to a construction method for preventing the collapse of underground continuous wall trenches in soft soil areas. Background Technology

[0002] Soft soil areas typically exhibit the following characteristics: uneven soil texture, thin layers of silt and sand, dull surface, low toughness, low to medium dry strength, mostly no swaying response, and slow local vibration response. Extra caution is required when excavating deep foundation pits in these areas. This is especially true during diaphragm wall construction, which involves extensive mechanized operations. Strengthening edge protection of trench sections is crucial during trenching to prevent collapse. In deep foundation pit excavation, vertical layering and symmetrical segmentation are the guiding principles. During longitudinal segmented excavation, a specific excavation plan must be developed, comprehensively considering environmental factors such as the surrounding geological conditions and hydrological characteristics. The distance of supports and the operational capabilities of specific construction equipment must also be taken into account when conducting vertical layered excavation.

[0003] Currently, the equipment used for foundation pit excavation generally includes excavators, grab bucket trenchers, and mud pumps, but there is very little involvement in anti-collapse and stabilization equipment during trench excavation. For example, patent CN109594564A discloses a method for preventing collapse during open-cut excavation of deep foundation pits in subway construction, including the following steps: S1: Using wellpoint dewatering, dewatering wells are laid around the foundation pit to form a dewatering curtain for dewatering around the foundation pit; S2: Rotary drilling of bored piles, installation of casings, and grouting to construct retaining piles; S3: Construction of cap beam concrete support, excavating the surface of the foundation pit to the top elevation of the cap beam concrete support, excavating a trench to the required depth at the location of the cap beam concrete support, pouring reinforced concrete in the trench, and constructing the cap beam concrete support; S4: Deep foundation pit excavation, construction of walkways, and erection of steel supports; S5: Slope repair, soil nail drilling, installation of soil nails, soil nail grouting, spraying the bottom layer of concrete, hanging steel mesh, installing soil nail bearing plates, spraying the surface layer of concrete, and spraying concrete with mesh between piles; S6: Repeating steps S4 to S5 until the required foundation pit depth is reached. However, this invention patent still does not address the stability during trench excavation. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a construction method for preventing the collapse of underground continuous wall trenches in soft soil areas.

[0005] The technical solution of this invention is:

[0006] A construction method for preventing the collapse of underground continuous wall in soft soil areas includes the following steps:

[0007] S1. Guide wall construction: Excavate a guide wall around the edge of the foundation pit to be excavated. The guide wall is 1 to 1.2m wide and 1.8 to 2.5m deep. After pumping out the water accumulated in the guide wall pit, erect the formwork and pour concrete. A concrete cushion layer is provided at the base of the guide wall.

[0008] S2. Trenching Construction of Continuous Wall: A grab trenching machine is used to excavate the continuous wall inside the guide wall. The continuous wall is divided into a first trench section and a second trench section. After excavating one first trench section, a second trench section is opened in the middle before the next first trench section is excavated. After the excavation of two first trench sections is completed, the second trench section in the middle is excavated. The width of the first trench section and the second trench section is 80-90cm, and the length of the first trench section and the second trench section is the same. During the excavation of the first trench section and the second trench section, anti-collapse components are used to clean the trench wall and replenish the mud. The mud level is 0.5-0.7m higher than the groundwater level. After all the first trench sections and the second trench section are excavated, the continuous wall trench is formed.

[0009] S3. Continuous wall pouring: hoist the steel cage into the continuous wall trench. Within 4 hours after all the steel cages are hoisted into the continuous wall trench, concrete is poured. Install two concrete ducts in the steel cages in each first or second trench section. Pour concrete into the ducts. Keep the bottom of the ducts 2 to 4 meters below the concrete surface. The concrete height rises at a rate of 3 to 5 meters per hour.

[0010] S4. Excavation of the foundation pit: Excavation of the foundation pit is carried out using an excavator inside the diaphragm wall.

[0011] Furthermore, the thickness of the concrete cushion layer in step S1 is 5 to 6 cm.

[0012] Note: The stability of the guide wall is maintained by a concrete pad layer.

[0013] Furthermore, in step S3, the guide pipe section is 2.5m long, the lowest section is 4m long, the bottom of the guide pipe is 300-500mm from the bottom, the guide pipe spacing is 3m, the guide pipe is 1.5m from the end of the first and second trench sections, and the difference in concrete surface height between the two guide pipes is no more than 0.3m.

[0014] Explanation: By optimizing and adjusting the specific parameters in step S3, the continuous wall can be poured to meet the production quality requirements, ultimately forming a stable and solid concrete continuous wall.

[0015] Furthermore, the anti-collapse component in step S2 includes fixed rails located on both sides of the guide wall, and telescopic uprights located between the two fixed rails;

[0016] The fixed track has a first groove in the middle and a second groove at the top. A drive motor is slidably connected to the second groove of the front fixed track, and a first slider is slidably connected to the second groove of the rear fixed track. The drive motor and the first slider are connected to each other by a fixed rod. The right side of the fixed rod is fixedly connected to the top of the telescopic pole. An extension rod is provided at the bottom of the telescopic pole, and a roller is provided at the bottom of the extension rod. A rotating motor is provided on each of the front and rear sides of the bottom of the telescopic pole. Several connecting rods are provided at equal intervals around the output shaft of the rotating motor. A scraper for cleaning the groove wall of the continuous wall is provided at the end of the connecting rod.

[0017] A telescopic grout guide pipe is fixedly installed on the right side of the telescopic upright. A telescopic bend is provided at the bottom of the telescopic grout guide pipe. The upper vertical section of the telescopic bend is slidably connected to the bottom of the telescopic grout guide pipe and extends into the interior of the telescopic grout guide pipe. The lower bent section of the telescopic bend faces to the right. Limiting push rods are symmetrically provided on both sides of the lower part of the vertical section of the telescopic bend. The limiting push rods are connected to the scraper in the rotating state to lift the telescopic bend upward.

[0018] Note: By optimizing the specific structure of the anti-collapse component, the stability of the trench wall can be maintained during continuous wall trenching construction, preventing collapse, which plays an important role in excavation in soft soil areas.

[0019] Furthermore, the drive motor has a drive wheel at its front output end, and a gear shaft is meshed below the drive wheel. The gear shaft meshes with a toothed groove on the lower surface of the first slide groove of the fixed track located in front. A positioning rod is rotatably connected at the rear center of the gear shaft. The positioning rod is fixedly connected to the lower part of the front side wall of the first slider. The top of the positioning rod is fixedly connected to the bottom of the fixed rod through several fixing blocks. A third slide groove is provided at the center of the surfaces of the two second slide grooves. The bottom of the drive motor is slidably connected to the third slide groove of the fixed track located in front through a second slider. A limiting groove is provided on the rear side of the first slider. The top wall of the limiting groove is slidably connected to the third slide groove of the fixed track located behind through a third slider. The first slider below the corresponding limiting groove is slidably connected to the first slide groove of the fixed track located behind.

[0020] Explanation: The entire device is moved horizontally by a drive wheel in conjunction with a gear shaft, allowing the entire anti-collapse component to move continuously behind the grab bucket trenching machine to continuously clean the trench walls and replace and replenish mud.

[0021] Preferably, the top of the telescopic slurry guide pipe is provided with a slurry inlet pipe, and the bottom of the slurry inlet pipe is slidably connected to the third slide groove of the fixed track located behind it via a fourth slider.

[0022] Explanation: By sliding the grout inlet pipe to the third chute, the grout inlet pipe and the anti-collapse component move synchronously, maintaining the stability of the anti-collapse component.

[0023] Furthermore, the top of the telescopic grout guide pipe is fixedly connected to the top right side wall of the telescopic pole via a first buckle, and the bottom of the telescopic grout guide pipe is fixedly connected to the bottom right side wall of the telescopic pole via a second buckle.

[0024] Note: The two clips ensure that the telescopic grout pipe and the telescopic pole are always synchronized and stable.

[0025] Furthermore, the rotating motor has three scrapers, and the end of the limiting push rod is provided with a groove for engaging with the scraper. The top two sides of the telescopic bend are symmetrically provided with fifth sliders, and the two fifth sliders are slidably connected to the fourth sliding grooves symmetrically provided on both sides of the bottom inner wall of the telescopic guide pipe. The fourth sliding grooves extend obliquely upward to allow the telescopic bend to rotate during the upward movement, so that when the telescopic bend moves to a height of 15-30cm, the scraper disengages from the groove and the telescopic bend automatically resets under the action of gravity, completing the reciprocating up and down movement of the telescopic bend.

[0026] Explanation: By optimizing the upward movement of the telescopic bend and its coordination with the scraper, the upward movement and rotation of the telescopic bend are cleverly synchronized, and it can automatically reset to achieve reciprocating motion without the need for an additional power source. This achieves integrated structure and function, thus preventing the telescopic bend from continuously sucking in mud from the bottom of the tank for a long time. This also avoids the instability of pressure at that point caused by continuous mud sucking in for a long time, which could easily lead to tank wall collapse and detachment.

[0027] Furthermore, in step S2, when excavating the first or second trench section, after the overall excavation depth reaches 3-4m, anti-collapse components are installed. Before installing the anti-collapse components, an external mud pump is used to pump out slurry, and the pumped slurry is filtered through a vibrating screen to remove the slag and soil, and then an external water supply pipe is used to replenish water and slurry. After installing the anti-collapse components, the telescopic slurry pipe is used to pump out slurry, which is then filtered through a vibrating screen to remove the slag and soil, and then an external water supply pipe is used to replenish water and slurry.

[0028] Explanation: By combining the structural optimization adjustment step S2 with the anti-collapse component, the probability of trench wall collapse during the excavation of continuous wall in soft soil areas is reduced.

[0029] The beneficial effects of this invention are:

[0030] (1) The construction method for preventing trench wall collapse in soft soil areas of the present invention focuses on optimizing and adjusting a series of steps before the excavation of the foundation pit. In view of the problem that collapse is prone to occur in soft soil areas, technical improvements have been made from the construction of guide walls to the construction of trench walls and the pouring of trench walls, so as to ensure the stability of the subsequent foundation pit excavation. In particular, the parameters and related structures for preventing trench wall collapse during the construction of trench walls have been optimized, which greatly reduces the probability of trench wall collapse during the construction of trench walls in soft soil areas.

[0031] (2) The construction method for preventing trench wall collapse in underground continuous wall in soft soil areas according to the present invention, combined with the specific requirements of the steps, also provides a special anti-collapse component, which can maintain the stability of the trench wall during continuous wall trenching construction and prevent collapse. It plays an important role in the excavation of soft soil areas. The most important improvement is that the bottom scraper is set to continuously clean the trench wall, and the structure of the telescopic bend that sucks the bottom mud is optimized in combination with the rotation mode of the two sets of scrapers. It cleverly realizes the upward movement and rotation of the telescopic bend synchronously, and can automatically reset to achieve reciprocating motion. No additional power source is set, realizing the integration of structure and function. This avoids the continuous suction of the bottom mud at the end of the telescopic bend for a long time in the same location. This also avoids the situation where the pressure at that point is unstable due to the continuous suction of mud at the same location for a long time, which can easily lead to the collapse and fall off of the trench wall. The structure of the anti-collapse component, in turn, limits the specific steps of continuous wall trenching excavation and the timing of the use of the anti-collapse component, and clarifies the use of the anti-collapse component, which is conducive to the promotion and use of the construction in soft soil areas. Attached Figure Description

[0032] Figure 1 This is a flowchart of a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention;

[0033] Figure 2 This is a schematic diagram of the overall structure of the anti-collapse component in a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention.

[0034] Figure 3 This is a schematic diagram of the bottom structure of the anti-collapse component in a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention.

[0035] Figure 4 This is a schematic diagram of the drive motor and related structural components of the anti-collapse component in a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention.

[0036] Figure 5 This is a cross-sectional view of the connection between the second slider and the third chute in a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention.

[0037] Figure 6 This is a side view of the first slider of the anti-collapse component in a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention.

[0038] Figure 7 This is a side view of the grout inlet pipe of the anti-collapse component in a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention.

[0039] Figure 8 This is a schematic diagram showing the position of the telescopic bend before the scraper and the limiting push rod of the anti-collapse component in the construction method of the underground continuous wall anti-collapse in soft soil area according to the present invention.

[0040] Figure 9 This is a schematic diagram showing the position of the telescopic bend after the scraper of the anti-collapse component contacts the limiting push rod in a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention.

[0041] Figure 10 This is a schematic diagram of the connection structure between the limiting push rod and the telescopic grout pipe of the anti-collapse component in a construction method for preventing the collapse of underground continuous wall in soft soil areas according to the present invention.

[0042] Figure 11 This is a front view of the orientation of the fourth chute structure inside the telescopic grout guide pipe of the anti-collapse component in the construction method of the underground continuous wall anti-collapse in soft soil areas according to the present invention.

[0043] Among them, 1-fixed track, 11-first slide groove, 111-tooth groove, 12-second slide groove, 13-third slide groove, 2-telescopic upright, 21-extension rod, 22-roller, 3-drive motor, 31-drive wheel, 32-gear shaft, 33-positioning rod, 34-second slider, 4-first slider, 41-limiting groove, 42-third slider, 5-fixed rod, 51-fixed block, 6-rotating motor, 61-connecting rod, 62-scraper, 7-telescopic slurry guide pipe, 71-slurry inlet pipe, 72-fourth slider, 73-first buckle, 74-second buckle, 75-fourth slide groove, 8-telescopic bend, 81-limiting push rod, 82-groove, 83-fifth slider. Detailed Implementation

[0044] Example 1

[0045] A construction method for preventing trench wall collapse in underground continuous wall systems in soft soil areas, such as... Figure 1 As shown, it includes the following steps:

[0046] S1. Guide wall construction: Excavate a guide wall around the edge of the foundation pit to be excavated. The guide wall is 1.1m wide and 2m deep. After pumping out the water accumulated in the guide wall pit, erect the formwork and pour concrete. The base of the guide wall is provided with a concrete cushion layer with a thickness of 5cm.

[0047] S2. Trenching Construction of Continuous Wall: A grab trenching machine is used to excavate the continuous wall inside the guide wall. The continuous wall is divided into a first trench segment and a second trench segment. After excavating one first trench segment, a second trench segment is separated in the middle before the next first trench segment is excavated. After the excavation of two first trench segments is completed, the second trench segment in the middle is excavated. The width of the first trench segment and the second trench segment is 85cm, and the length of the first trench segment and the second trench segment is the same. During the excavation of the first trench segment and the second trench segment, anti-collapse components are used to clean the trench wall and replenish the mud. The mud level is 0.6m higher than the groundwater level. After all the first trench segments and the second trench segment are excavated, the continuous wall trench is formed.

[0048] The anti-collapse component is a grouting pipe that is tightly attached to the trench wall;

[0049] S3. Continuous wall pouring: Hoist the steel cage into the continuous wall trench. Within 4 hours after all steel cages are hoisted into the continuous wall trench, pour concrete. Install two concrete guide pipes in the steel cages in each first or second trench section. Pour concrete into the guide pipes. The bottom of the guide pipe should be buried 3m below the concrete surface. The concrete height rise rate is 4m / h. The length of each guide pipe section is 2.5m. The length of the lowest section is 4m. The bottom of the guide pipe is 400mm from the bottom. The distance between the guide pipes is 3m. The distance between the guide pipes and the ends of the first and second trench sections is 1.5m. The height difference between the concrete surfaces at the two guide pipes is no more than 0.3m.

[0050] S4. Excavation of the foundation pit: Excavation of the foundation pit is carried out using an excavator inside the diaphragm wall;

[0051] Example 2

[0052] The difference between this embodiment and Embodiment 1 is that the specific parameter settings are different.

[0053] S1. Guide wall construction: Excavate a guide wall around the edge of the foundation pit to be excavated. The guide wall is 1m wide and 1.8m deep. After pumping out the water accumulated in the guide wall pit, erect the formwork and pour concrete. The base of the guide wall is provided with a concrete cushion layer with a thickness of 5cm.

[0054] S2. Trenching construction of continuous wall: The width of the first and second trench sections is 80cm, and the mud slurry level is 0.5m above the groundwater level;

[0055] S3. Continuous wall casting: The bottom end of the tremie pipe is buried 2m below the concrete surface, the concrete height rises at a rate of 3m / h, the length of the tremie pipe section is 2.5m, the length of the lowest section is 4m, the bottom of the tremie pipe is 300mm from the bottom, the spacing between the tremie pipes is 3m, the distance between the tremie pipes and the ends of the first and second trench sections is 1.5m, and the height difference between the concrete surfaces at the two tremie pipes is no more than 0.3m.

[0056] Example 3

[0057] The difference between this embodiment and Embodiment 1 is that the specific parameter settings are different.

[0058] S1. Guide wall construction: Excavate a guide wall around the edge of the foundation pit to be excavated. The guide wall is 1.2m wide and 2.5m deep. After pumping out the water accumulated in the guide wall pit, erect the formwork and pour concrete. The base of the guide wall is provided with a concrete cushion layer with a thickness of 6cm.

[0059] S2. Trenching construction of continuous wall: The width of the first and second trench sections is 90cm, and the mud slurry level is 0.7m above the groundwater level;

[0060] S3. Continuous wall casting: The bottom end of the tremie pipe is buried 4m below the concrete surface, the concrete height rises at a rate of 5m / h, the length of the tremie pipe section is 2.5m, the length of the lowest section is 4m, the bottom of the tremie pipe is 500mm from the bottom, the spacing between the tremie pipes is 3m, the distance between the tremie pipes and the ends of the first and second trench sections is 1.5m, and the height difference between the concrete surfaces at the two tremie pipes is 0.3m.

[0061] Example 4

[0062] This embodiment further defines the anti-collapse component in step S2 of embodiment 1, such as... Figure 2 As shown, the anti-collapse component includes fixed rails 1 located on both sides of the guide wall, and telescopic uprights 2 located between the two fixed rails 1;

[0063] like Figure 2 , 3 As shown, a first sliding groove 11 is provided in the middle of the fixed track 1, and a second sliding groove 12 is provided at the top of the fixed track 1. A drive motor 3 is slidably connected to the second sliding groove 12 of the front fixed track 1, and a first slider 4 is slidably connected to the second sliding groove 12 of the rear fixed track 1. The drive motor 3 and the first slider 4 are connected to each other by a fixed rod 5. The right side of the fixed rod 5 is fixedly connected to the top of the telescopic pole 2. An extension rod 21 is provided at the bottom of the telescopic pole 2, and a roller 22 is provided at the bottom of the extension rod 21. A rotating motor 6 is provided on each of the front and rear sides of the bottom of the telescopic pole 2. Three connecting rods 61 are provided at equal intervals around the output shaft of the rotating motor 6. A scraper 62 for cleaning the trough wall of the continuous wall is provided at the end of the connecting rod 61.

[0064] like Figures 7-11As shown, a telescopic grout guide pipe 7 is fixedly installed on the right side of the telescopic pole 2. A telescopic bend pipe 8 is provided at the bottom of the telescopic grout guide pipe 7. The upper vertical section of the telescopic bend pipe 8 is slidably connected to the bottom of the telescopic grout guide pipe 7 and extends into the interior of the telescopic grout guide pipe 7. The lower bent section of the telescopic bend pipe 8 faces to the right. Limiting push rods 81 are symmetrically provided on both sides of the lower part of the vertical section of the telescopic bend pipe 8. The limiting push rods 81 are connected to the scraper 62 in the rotating state to lift the telescopic bend pipe 8 upward. A grout inlet pipe 71 is provided at the top of the telescopic grout guide pipe 7. The bottom of the grout inlet pipe 71 is slidably connected to the third slide groove 13 of a fixed track 1 located at the rear through a fourth slider 72. The top of the telescopic grout guide pipe 7 is fixedly connected to the top right side wall of the telescopic pole 2 through a first buckle 73. The bottom of the telescopic grout pipe 7 is fixedly connected to the bottom right side wall of the telescopic pole 2 via the second buckle 74. There are three scrapers 62 on the rotating motor 6. The end of the limiting push rod 81 is provided with a groove 82 for docking with the scraper 62. The top two sides of the telescopic bend 8 are symmetrically provided with fifth sliders 83. The two fifth sliders 83 are slidably connected to the fourth sliding grooves 75 symmetrically provided on the center of the bottom inner wall of the telescopic grout pipe 7. The fourth sliding grooves 75 extend obliquely upward to make the telescopic bend 8 rotate during the upward movement. This causes the scraper 62 to disengage from the groove 82 when the telescopic bend 8 moves up to a height of 20cm, and the telescopic bend 8 automatically resets under the action of gravity, completing the reciprocating up and down movement of the telescopic bend 8.

[0065] like Figure 2 , 4 As shown in Figure 6, the drive motor 3 has a drive wheel 31 at the front output end. A gear shaft 32 is meshed with the drive wheel 31 below. The gear shaft 32 is meshed with the toothed groove 111 on the lower surface of the first slide groove 11 of the fixed track 1 located in front. A positioning rod 33 is rotatably connected at the rear center of the gear shaft 32. The positioning rod 33 is fixedly connected to the lower part of the front side wall of the first slider 4. The top of the positioning rod 33 is fixedly connected to the bottom of the fixed rod 5 through two fixing blocks 51. A third slide groove 13 is provided at the center of the surface of the two second slide grooves 12. The bottom of the drive motor 3 is slidably connected to the third slide groove 13 of the fixed track 1 located in front through the second slider 34. A limiting groove 41 is provided on the rear side of the first slider 4. The top wall of the limiting groove 41 is slidably connected to the third slide groove 13 of the fixed track 1 located behind through the third slider 42. The first slider 4 below the corresponding limiting groove 41 is slidably connected to the first slide groove 11 of the fixed track 1 located behind.

[0066] Meanwhile, in step S2, when excavating the first or second trench section, after the overall excavation depth reaches 3.5m, anti-collapse components are installed. Before installing the anti-collapse components, an external mud pump is used to pump out the mud, and the pumped mud is filtered through a vibrating screen to remove the slag and then an external water supply pipe is used to replenish the mud. After installing the anti-collapse components, a telescopic slurry pipe 7 is used to pump out the mud, which is then filtered through a vibrating screen to remove the slag and then an external water supply pipe is used to replenish the mud.

[0067] Example 5

[0068] The difference between this embodiment and embodiment 4 is that the specific parameter settings are different.

[0069] The fourth groove 75 extends obliquely upward to allow the telescopic bend 8 to rotate during the upward movement, so that when the telescopic bend 8 moves to a height of 15cm, the scraper 62 disengages from the groove 82 and the telescopic bend 8 automatically resets under the action of gravity, thus completing the reciprocating up and down movement of the telescopic bend 8.

[0070] Meanwhile, in step S2, when excavating the first or second trench section, anti-collapse components are deployed after the overall excavation depth reaches 3m.

[0071] Example 6

[0072] The difference between this embodiment and embodiment 4 is that the specific parameter settings are different.

[0073] The fourth groove 75 extends obliquely upward to allow the telescopic bend 8 to rotate during its upward movement. This causes the scraper 62 to disengage from the groove 82 when the telescopic bend 8 reaches a height of 30cm, and the telescopic bend 8 to automatically reset under gravity, thus completing the reciprocating up and down movement of the telescopic bend 8.

[0074] Meanwhile, in step S2, when excavating the first or second trench section, anti-collapse components are deployed after the overall excavation depth reaches 4m.

[0075] Working principle: The working principle of the anti-collapse component of the present invention will be further explained below in conjunction with the method of the present invention.

[0076] In use, when the first or second trench section is excavated to a specified depth in step S2, the anti-collapse component is installed. First, two fixed rails 1 are installed, followed by other structural components. The telescopic uprights 2 and telescopic grout pipes 7 extend out, so that the rollers 22 contact the bottom of the trench and can roll. As the grab bucket moves after continuously grabbing soil, the drive motor 3 needs to be turned on to make the entire anti-collapse component move with the grab bucket. The drive wheel 31 drives the gear shaft 32 to rotate under meshing action, so that it moves inside the tooth groove 111, thereby driving the positioning rod 33, the first slider 4 and the fixed rod 5 to move, realizing the movement of the telescopic uprights 2 and the telescopic grout pipes 7.

[0077] Having clarified the movement method of the anti-collapse components, let's examine the working principle of mud suction. First, connect the mud pump and vibrating screen to the external mud inlet pipe 71. After starting, the mud from the bottom of the tank is sucked through the telescopic guide pipe 7 and the telescopic bend pipe 8. If mud suction is maintained in one position, it can easily lead to tank wall collapse. Therefore, the inlet of the telescopic bend pipe 8 needs to be moved. Turning on the rotating motor 6 causes it to drive the connecting rod 61 and each scraper 62 to rotate. While cleaning the tank wall, when the scraper 62 passes through the groove 82 of the limiting push rod 81, it lifts the groove 82 and the limiting push rod upwards. This allows the top of the telescopic bend pipe 8 to slide into the bottom of the telescopic guide pipe 7, achieving upward lifting. Figure 8 The state becomes Figure 9 Medium state;

[0078] at the same time, Figure 11 As we can see, the fourth slide 75 is an inclined section, which allows the fifth slider 83 to turn while sliding along the fourth slide 75. This is manifested in the telescopic bend 8 as rotation. During the upward movement, it can rotate through a certain angle, causing the limiting push rod 81 to leave the rotation range of the scraper 62 vertically. This allows the telescopic bend 8 to automatically descend and reset under the action of gravity, and also avoids stress bending caused by the scraper 62 continuously raising the limiting push rod 81. Ultimately, the two functions of cleaning the tank wall and the mud inlet are carried out simultaneously without the need for an additional power source.

[0079] It should be noted that the two sets of scrapers 62 on both sides always maintain cross-operation during rotation. That is, after one of the scrapers 62 on the front side achieves a contact cycle with the front limit push rod 81, and the telescopic bend 8 is completely moved down and reset, one of the scrapers 62 on the rear side then contacts the rear limit push rod 81, maintaining a stable up and down movement cycle.

Claims

1. A construction method for preventing trench wall collapse in underground continuous wall systems in soft soil areas, characterized in that, Includes the following steps: S1. Guide wall construction: Excavate a guide wall around the edge of the foundation pit to be excavated. The guide wall is 1 to 1.2m wide and 1.8 to 2.5m deep. After pumping out the water accumulated in the guide wall pit, erect the formwork and pour concrete. A concrete cushion layer is provided at the base of the guide wall. S2. Trenching Construction of Continuous Wall: A grab trenching machine is used to excavate the continuous wall inside the guide wall. The continuous wall is divided into a first trench section and a second trench section. After excavating one first trench section, a second trench section is opened in the middle before the next first trench section is excavated. After the excavation of two first trench sections is completed, the second trench section in the middle is excavated. The width of the first trench section and the second trench section is 80-90cm, and the length of the first trench section and the second trench section is the same. During the excavation of the first trench section and the second trench section, anti-collapse components are used to clean the trench wall and replenish the mud. The mud level is 0.5-0.7m higher than the groundwater level. After all the first trench sections and the second trench section are excavated, the continuous wall trench is formed. The anti-collapse component in step S2 includes fixed rails (1) located on both sides of the guide wall, and telescopic uprights (2) located between the two fixed rails (1); The fixed track (1) has a first groove (11) in the middle and a second groove (12) at the top. A drive motor (3) is slidably connected to the second groove (12) of the fixed track (1) in front and a first slider (4) is slidably connected to the second groove (12) of the fixed track (1) in the rear. The drive motor (3) and the first slider (4) are connected to each other by a fixed rod (5). The right side of the fixed rod (5) is fixedly connected to the top of the telescopic pole (2). The telescopic pole (2) has an extension rod (21) at the bottom and a roller (22) at the bottom of the extension rod (21). The telescopic pole (2) has a rotating motor (6) on each side at the bottom. The output shaft of the rotating motor (6) has several connecting rods (61) at equal intervals around its circumference. The end of the connecting rod (61) has a scraper (62) for cleaning the groove wall of the continuous wall. The telescopic pole (2) is fixedly provided with a telescopic grout guide pipe (7) on the right side. The bottom of the telescopic grout guide pipe (7) is provided with a telescopic bend pipe (8). The upper vertical section of the telescopic bend pipe (8) is slidably connected to the bottom of the telescopic grout guide pipe (7) and extends into the inside of the telescopic grout guide pipe (7). The lower bent section of the telescopic bend pipe (8) faces to the right. The lower two sides of the vertical section of the telescopic bend pipe (8) are symmetrically provided with limiting push rods (81). The limiting push rods (81) are connected to the scraper (62) in the rotating state to lift the telescopic bend pipe (8) upward. S3. Continuous wall pouring: hoist the steel cage into the continuous wall trench. Within 4 hours after all the steel cages are hoisted into the continuous wall trench, concrete is poured. Install two concrete ducts in the steel cages in each first or second trench section. Pour concrete into the ducts. Keep the bottom of the ducts 2 to 4 meters below the concrete surface. The concrete height rises at a rate of 3 to 5 meters per hour. S4. Excavation of the foundation pit: Excavation of the foundation pit is carried out using an excavator inside the diaphragm wall.

2. The construction method for preventing trench wall collapse in underground continuous wall in soft soil areas according to claim 1, characterized in that, The thickness of the concrete cushion layer in step S1 is 5-6 cm.

3. The construction method for preventing trench wall collapse in underground continuous wall in soft soil areas according to claim 1, characterized in that, In step S3, the guide pipe section is 2.5m long, the lowest section is 4m long, the bottom of the guide pipe is 300-500mm from the bottom, the guide pipe spacing is 3m, the guide pipe is 1.5m from the end of the first and second trench sections, and the difference in concrete surface height between the two guide pipes is no more than 0.3m.

4. The construction method for preventing trench wall collapse in underground continuous wall in soft soil areas according to claim 1, characterized in that, The drive motor (3) has a drive wheel (31) at its front output end. A gear shaft (32) is meshed with the drive wheel (31) below it. The gear shaft (32) meshes with a toothed groove (111) on the lower surface of the first slide groove (11) of the fixed track (1) located in front. A positioning rod (33) is rotatably connected at the rear center of the gear shaft (32). The positioning rod (33) is fixedly connected to the lower part of the front side wall of the first slider (4). The top of the positioning rod (33) is fixedly connected to the bottom of the fixed rod (5) through several fixing blocks (51). Next, a third slide groove (13) is provided at the center of the surface of each of the two second slide grooves (12). The bottom of the drive motor (3) is slidably connected to the third slide groove (13) of a fixed track (1) located in front through the second slider (34). A limiting groove (41) is provided on the rear side of the first slider (4). The top wall of the limiting groove (41) is slidably connected to the third slide groove (13) of a fixed track (1) located behind through the third slider (42). The first slider (4) below the limiting groove (41) is slidably connected to the first slide groove (11) of a fixed track (1) located behind.

5. A construction method for preventing trench wall collapse in underground continuous wall systems in soft soil areas according to claim 4, characterized in that, The top of the telescopic slurry guide pipe (7) is provided with a slurry inlet pipe (71), and the bottom of the slurry inlet pipe (71) is slidably connected to the third slide groove (13) of the fixed track (1) located behind it via a fourth slider (72).

6. A construction method for preventing trench wall collapse in underground continuous wall systems in soft soil areas according to claim 1, characterized in that, The top of the telescopic grout pipe (7) is fixedly connected to the top right side wall of the telescopic pole (2) via a first buckle (73), and the bottom of the telescopic grout pipe (7) is fixedly connected to the bottom right side wall of the telescopic pole (2) via a second buckle (74).

7. A construction method for preventing trench wall collapse in underground continuous wall systems in soft soil areas according to claim 1, characterized in that, The rotating motor (6) has three scrapers (62). The end of the limiting push rod (81) is provided with a groove (82) for docking with the scraper (62). The top two sides of the telescopic bend (8) are symmetrically provided with fifth sliders (83). The two fifth sliders (83) are slidably connected to the fourth sliding grooves (75) symmetrically provided on both sides of the bottom inner wall of the telescopic guide pipe (7). The fourth sliding groove (75) extends obliquely upward to make the telescopic bend (8) rotate during the upward movement. When the telescopic bend (8) moves up to a height of 15-30cm, the scraper (62) disengages from the groove (82) and the telescopic bend (8) automatically resets under the action of gravity, completing the reciprocating up and down movement of the telescopic bend (8).

8. A construction method for preventing trench wall collapse in underground continuous wall systems in soft soil areas according to claim 1, characterized in that, In step S2, when excavating the first or second trench section, after the overall excavation depth reaches 3 to 4 m, the anti-collapse components are installed. Before installing the anti-collapse components, an external mud pump is used to pump mud, and the pumped mud is filtered through a vibrating screen to remove the slag and soil. Then, an external water supply pipe is used to replenish water and mud. After installing the anti-collapse components, the telescopic slurry pipe (7) is used to pump mud, which is then filtered through a vibrating screen to remove the slag and soil. Finally, an external water supply pipe is used to replenish water and mud.

Images