Construction method for preventing groove wall collapse of underground diaphragm wall in soft soil area

Abstract

The invention discloses a construction method for preventing a groove wall of an underground diaphragm wall in a soft soil area from collapsing. The construction method comprises the following steps that S1, a guide wall is constructed; s2, continuous wall grooving construction is conducted; s3, continuous wall pouring; and S4, the foundation pit is excavated. In the step S2, an anti-collapse assembly comprises fixed rails located on the two sides of the guide wall and a telescopic vertical rod located between the two fixed rails, a telescopic slurry guide pipe is fixedly arranged on the right side of the telescopic vertical rod, and a telescopic bent pipe is arranged at the bottom of the telescopic slurry guide pipe. According to the method, a series of steps before excavation of the foundation pit are optimized and adjusted emphatically, the stability during subsequent excavation of the foundation pit is guaranteed aiming at the problem that collapse is prone to occurring in a soft soil area, especially optimization on parameters and related structures is conducted on collapse prevention of the groove wall during continuous wall grooving construction, and the construction efficiency is improved. And the occurrence probability of groove wall collapse during grooving excavation of the continuous wall constructed in the soft soil area is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a construction method for preventing trench wall collapse from occurring in an underground continuous wall in a soft soil area. Background Art

[0002] The characteristics of soft soil areas are usually: uneven soil, a small amount of thin layers of silt and silt, dull soil surface, low toughness, medium to low dry strength, mostly no shaking response, slow local shaking response, etc. For these areas, more attention should be paid when excavating deep foundation pits. Especially in the construction of ground-connected walls, there are many mechanical operations during the construction of ground-connected walls, and the protection of the edges of the trench sections needs to be strengthened during the trenching process, otherwise it is easy to cause collapse. In the process of excavating deep foundation pits, vertical stratification and longitudinal segmentation according to symmetry are the principles to be followed in excavation. In the process of longitudinal segmented excavation, a specific excavation plan needs to be formulated, and environmental factors such as geological conditions and hydrological characteristics around the construction site need to be comprehensively considered. The distance of support setting and the operating capacity of specific construction equipment need to be considered when conducting vertical layered excavation construction.

[0003] At present, the equipment used for foundation pit excavation generally includes excavators, grab trenching machines, mud pumps, etc., and anti-collapse stabilization equipment during trench excavation is rarely involved. For example, patent CN109594564A discloses a method for preventing collapse of deep foundation pits in subways, which includes the following steps: S1: using the well point dewatering method, laying dewatering wells around the foundation pit to form a dewatering curtain, and dewatering around the foundation pit; S2: drilling bored piles, burying casings, and grouting to make surrounding piles; S3: constructing crown beam concrete support, excavating the surface of the foundation pit to the top elevation of the crown beam concrete support, digging a groove to the required depth at the position of the crown beam concrete support, pouring reinforced concrete in the groove, and constructing crown beam concrete support; S4: excavating the deep foundation pit, constructing a horseway, and erecting steel supports; S5: repairing the slope, drilling holes for soil nails, installing soil nails, grouting soil nails, spraying the bottom layer of the wall concrete, hanging steel mesh, installing soil nail pressure plates, spraying the surface layer of the wall concrete, and hanging mesh between piles to spray concrete; S6: repeating steps S4 to S5 until the required foundation pit depth is constructed. However, the invention patent still does not involve the anti-collapse stability during trench excavation. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention provides a construction method for preventing trench wall collapse of an underground continuous wall in a soft soil area.

[0005] The technical solution of the present invention is:

[0006] A construction method for preventing trench wall collapse by underground continuous wall in soft soil area comprises the following steps:

[0007] S1. Guide wall construction: excavate the guide wall around the edge of the foundation pit to be excavated, with a width of 1 to 1.2 m and a depth of 1.8 to 2.5 m. After draining the water in the guide wall pit, formwork is erected and concrete is poured. A concrete cushion layer is provided at the base of the guide wall;

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

[0009] S3, continuous wall pouring: hoist the steel cage to the continuous wall slot, and pour concrete within 4 hours after all the steel cages are hoisted to the continuous wall slot. Install two concrete pipes in the steel cage in each first slot section or second slot section, and inject concrete into the pipes. The bottom of the pipe is buried 2 to 4 meters below the concrete surface, and the concrete height rise speed is 3 to 5 m / h;

[0010] S4. Foundation pit excavation: Use an excavator to excavate the foundation pit inside the continuous 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.

[0013] Furthermore, in step S3, the length of the conduit section is 2.5m, the length of the lowest section is 4m, the distance between the lower end of the conduit and the bottom is 300-500mm, the distance between the conduits is 3m, the distance between the conduits and the ends of the first and second trough sections is 1.5m, and the height difference of the concrete surfaces at the two conduits is not greater than 0.3m.

[0014] Note: By optimizing and adjusting the specific parameters in step S3, the continuous wall casting can meet the production quality requirements, and finally form a stable and strong concrete continuous wall.

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

[0016] A first slide groove is provided in the middle of the fixed track, a second slide groove is provided at the top of the fixed track, a driving motor is slidably connected to the second slide groove of a fixed track located in the front, and a first slider is slidably connected to the second slide groove of a fixed track located in the rear, the driving motor and the first slider are connected to each other through a fixed rod, the right side of the fixed rod is fixedly connected to the top of the telescopic vertical rod, an extension rod is provided at the bottom of the telescopic vertical rod, a roller is provided at the bottom of the extension rod, a rotating motor is respectively provided at the front and rear sides of the bottom of the telescopic vertical rod, a plurality of connecting rods are circumferentially and evenly spaced at the end of the output shaft of the rotating motor, and a scraper for cleaning the groove wall of the continuous wall is provided at the end of the connecting rod;

[0017] A telescopic slurry guide pipe is fixedly provided on the right side of the telescopic upright rod, a telescopic bent pipe is provided at the bottom of the telescopic slurry guide pipe, an upper vertical section of the telescopic bent pipe is slidably connected to the bottom of the telescopic slurry guide pipe and extends to the inside of the telescopic slurry guide pipe, a lower bending section of the telescopic bent pipe faces the right side, and limit push rods are symmetrically provided on both sides of the lower part of the vertical section of the telescopic bent pipe, the limit push rods are docked with the scraper in a rotating state to lift the telescopic bent pipe upward.

[0018] Description: By optimizing and limiting the specific structure of the anti-collapse components, the stability of the trench wall can be maintained during the continuous wall trench construction to prevent collapse, which plays an important role in excavation in soft soil areas.

[0019] Furthermore, a driving wheel disc is provided at the front output end of the driving motor, and a gear shaft is meshedly connected under the driving wheel disc, and the gear shaft is meshedly connected with a tooth groove provided on the lower surface of the first slide groove of a fixed rail located in the front, and a positioning rod is rotatably connected at the rear center of the gear shaft, and the positioning rod is fixedly connected to the lower portion of the front side wall of the first slider, and the top of the positioning rod is fixedly connected to the bottom of the fixed rod through a plurality of fixing blocks, and a third slide groove is provided at the center of the surfaces of the two second slide grooves, and the bottom of the driving motor is slidably connected to the third slide groove of a fixed rail located in the front through a second slider, and a limiting groove is provided on the rear side of the first slider, and the top wall of the limiting groove is slidably connected to the third slide groove of a fixed rail located in the rear through the third slider, and the first slider below the corresponding limiting groove is slidably connected to the first slide groove of a fixed rail located in the rear.

[0020] Description: The entire device can be translated by driving the wheel disc in conjunction with the gear shaft, so that the entire anti-collapse assembly can move continuously behind the grab slotting machine to continuously clean the slot wall and replace and replenish the mud.

[0021] Preferably, a slurry inlet pipe is provided at the top of the telescopic slurry guiding pipe, and the bottom of the slurry inlet pipe is slidably connected to the third sliding groove of one of the fixed rails located at the rear through a fourth sliding block.

[0022] Description: The slurry inlet pipe and the third chute are slidably connected to each other so that the slurry inlet pipe and the anti-collapse component move synchronously to maintain the stability of the anti-collapse component.

[0023] Furthermore, the top of the telescopic slurry guiding pipe is fixedly connected to the right side wall of the top of the telescopic upright pole through a first buckle, and the bottom of the telescopic slurry guiding pipe is fixedly connected to the right side wall of the bottom of the telescopic upright pole through a second buckle.

[0024] Description: The two buckles are set to always keep the telescopic slurry guide tube and the telescopic vertical rod synchronously extended and stable.

[0025] Furthermore, there are three scrapers on one rotating motor, and the end of the limiting push rod is provided with a groove for docking with the scraper. Fifth sliding blocks are symmetrically provided on both sides of the top of the telescopic elbow, and the two fifth sliding blocks are slidably connected with the fourth sliding grooves symmetrically provided on both sides of the inner wall of the bottom of the telescopic slurry guide pipe in a one-to-one corresponding manner. The fourth sliding groove extends obliquely upward and is used to make the telescopic elbow rotate during the upward movement, so that when the telescopic elbow moves to a height of 15 to 30 cm, the scraper and the groove are disengaged and the telescopic elbow is automatically reset under the action of gravity, completing the reciprocating up and down movement of the telescopic elbow.

[0026] Description: By optimizing the upward movement mode of the telescopic elbow and the coordination mode with the scraper, the upward movement and rotation of the telescopic elbow are cleverly synchronized, and it can automatically reset to achieve reciprocating motion. No additional power source is set, and the structural function is integrated, so that when the end of the telescopic elbow sucks the mud at the bottom of the trough, it can avoid continuous suction at the same place for a long time. This also avoids the situation where the pressure at this point is unstable and the trough wall collapses and falls off easily due to the continuous suction of mud at the same place for a long time.

[0027] Furthermore, in step S2, when excavating the first trench section or the second trench section, the anti-collapse component is deployed after the overall excavation depth reaches 3 to 4 m. Before the anti-collapse component is deployed, an external mud pump is used to pump slurry, and the extracted mud is filtered through a vibrating screen to remove the debris, and then an external water supply pipe is used to replenish water and slurry. After the anti-collapse component is deployed, the telescopic slurry guide pipe is used to pump mud, and the mud is filtered through a vibrating screen to remove the debris, and then an external water supply pipe is used to replenish water and slurry.

[0028] Note: By optimizing the excavation method of step S2 in combination with the anti-collapse component structure, the probability of trench wall collapse during trench excavation of continuous wall in soft soil areas can be reduced.

[0029] The beneficial effects of the present invention are:

[0030] (1) The present invention provides a construction method for preventing trench wall collapse in an underground continuous wall in a soft soil area, which focuses on optimizing and adjusting a series of steps before foundation pit excavation. Aiming at the problem of collapse that is prone to occur in soft soil areas, technical improvements are made from guide wall construction to continuous wall trenching construction and continuous wall casting, thereby ensuring stability during subsequent foundation pit excavation. In particular, the parameters and related structures for preventing trench wall collapse during continuous wall trenching construction are optimized, which greatly reduces the probability of trench wall collapse during continuous wall trenching in soft soil areas.

[0031] (2) The construction method of an underground continuous wall in a soft soil area for preventing trench wall collapse of the present invention is combined with the requirements of specific steps, and also provides a special anti-collapse component, which can maintain the stability of the trench wall and prevent collapse during the continuous wall trench construction, and plays an important role in the excavation of soft soil areas. Among them, the most important improvement is to set a trench bottom scraper to continuously clean the trench wall, and cooperate with the rotation mode of the two sets of scrapers to optimize the structure of the telescopic elbow for sucking the trench bottom mud, cleverly realize the upward movement and self-rotation of the telescopic elbow synchronously, and can automatically reset to achieve reciprocating motion, and no additional power source is set, realizing structural and functional integration, so that when the end of the telescopic elbow sucks the trench bottom mud, it avoids continuous suction at the same place for a long time, thus avoiding the situation that the pressure at the point is unstable and the trench wall collapses and falls off easily due to the continuous suction of mud at the same place for a long time, and in turn, according to the structure of the anti-collapse component, the specific steps of the continuous wall trench excavation and the use time of the anti-collapse component are limited, and the use method of the anti-collapse component is clarified, which is conducive to the promotion and use of construction in soft soil areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of a construction method of an underground continuous wall in a soft soil area to prevent trench wall collapse according to the present invention;

[0033] Figure 2 It is a schematic diagram of the overall structure of an anti-collapse assembly in a construction method for preventing trench wall collapse in an underground continuous wall in a soft soil area of ​​the present invention;

[0034] Figure 3 It is a schematic diagram of the bottom structure of an anti-collapse assembly in a construction method for preventing trench wall collapse of an underground continuous wall in a soft soil area according to the present invention;

[0035] Figure 4 It is a schematic diagram of a driving motor and related structural parts of an anti-collapse assembly in a construction method for preventing trench wall collapse of an underground continuous wall in a soft soil area of ​​the present invention;

[0036] Figure 5 It is a cross-sectional view of the connection between the second sliding block and the third sliding groove of the anti-collapse assembly in a construction method for preventing the trench wall from collapsing in an underground continuous wall in a soft soil area of ​​the present invention;

[0037] Figure 6 It is a side view of a first sliding block of an anti-collapse assembly in a construction method for preventing trench wall collapse of an underground continuous wall in a soft soil area according to the present invention;

[0038] Figure 7 It is a side view of a slurry inlet pipe of an anti-collapse assembly in a construction method for preventing trench wall collapse of an underground continuous wall in a soft soil area of ​​the present invention;

[0039] Figure 8 It is a schematic diagram of the position of the telescopic elbow before the scraper of the anti-collapse assembly contacts the limiting push rod in a construction method for preventing trench wall collapse of an underground continuous wall in a soft soil area of ​​the present invention;

[0040] Fig. 9 It is a schematic diagram of the position of the telescopic elbow after the scraper of the anti-collapse assembly contacts the limit push rod in a construction method for preventing trench wall collapse of an underground continuous wall in a soft soil area of ​​the present invention;

[0041] Fig.10 It is a schematic diagram of the connection structure of the limit push rod and the telescopic grouting pipe of the anti-collapse assembly in the construction method of the underground continuous wall in the soft soil area of ​​the present invention;

[0042] Fig.11 It is a front view showing the direction of the fourth chute structure inside the telescopic grouting pipe of the anti-collapse component in the construction method for preventing trench wall collapse of an underground continuous wall in a soft soil area of ​​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 vertical rod, 21-extension rod, 22-roller, 3-drive motor, 31-drive wheel disc, 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 bent pipe, 81-limiting push rod, 82-groove, 83-fifth slider. DETAILED DESCRIPTION

[0044] Example 1

[0045] A construction method for preventing trench wall collapse by underground continuous wall in soft soil area, such as Figure 1 As shown, the following steps are included:

[0046] S1. Guide wall construction: excavate the guide wall around the edge of the foundation pit to be excavated. The guide wall is 1.1m wide and 2m deep. After draining the water in the guide wall pit, the formwork is erected and concrete is poured. A concrete cushion layer is provided at the base of the guide wall. The thickness of the concrete cushion layer is 5cm.

[0047] S2. Continuous wall trenching construction: 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 a first trench section, a second trench section is separated in the middle, and the next first trench section is excavated. After the excavation of the two first trench sections is completed, the middle second trench section is excavated. The width of the first trench section and the second trench section is 85 cm, and the length of the first trench section and the second trench section is the same. When the first trench section and the second trench section are excavated, the anti-collapse assembly is used to clean the trench wall and replenish the mud. The mud liquid level is 0.6m higher than the groundwater level. After all the first trench sections and the second trench sections are excavated, a continuous wall trench is formed;

[0048] The anti-collapse component is a grouting pipe that is close to the tank wall;

[0049] S3, continuous wall pouring: hoist the steel cage to the continuous wall slot, and pour concrete within 4 hours after all the steel cages are hoisted to the continuous wall slot. Install two concrete pipes in the steel cage in each first slot section or second slot section, and inject concrete into the pipes. The bottom of the pipe is buried below the concrete surface and maintained at 3m. The concrete height rise speed is 4m / h. The pipe section length is 2.5m, the lowest section length is 4m, the lower end of the pipe is 400mm from the bottom, the pipe spacing is 3m, the pipe is 1.5m away from the first slot section and the second slot section end, and the height difference of the concrete surface at the two pipes is not more than 0.3m;

[0050] S4. Excavation of foundation pit: Use an excavator to excavate the foundation pit inside the continuous 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 the guide wall around the edge of the foundation pit to be excavated. The guide wall is 1m wide and 1.8m deep. After draining the water in the guide wall pit, formwork is erected and concrete is poured. A concrete cushion layer is provided at the base of the guide wall. The thickness of the concrete cushion layer is 5cm.

[0054] S2. Continuous wall trench construction: The width of the first trench section and the second trench section is 80cm, and the mud liquid level is 0.5m higher than the groundwater level;

[0055] S3. Continuous wall casting: The bottom end of the conduit is buried 2m below the concrete surface, the concrete height rises at a speed of 3m / h, the conduit section length is 2.5m, the lowest section length is 4m, the lower end of the conduit is 300mm from the bottom, the conduit spacing is 3m, the conduit is 1.5m away from the end of the first and second trough sections, and the height difference of the concrete surface at the two conduits is not 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 the guide wall around the edge of the foundation pit to be excavated. The guide wall is 1.2m wide and 2.5m deep. After draining the water in the guide wall pit, formwork is erected and concrete is poured. A concrete cushion layer is provided at the base of the guide wall. The thickness of the concrete cushion layer is 6cm.

[0059] S2, continuous wall trench construction: the width of the first trench section and the second trench section is 90cm, and the mud liquid level is 0.7m higher than the groundwater level;

[0060] S3. Continuous wall casting: The bottom end of the conduit is buried 4m below the concrete surface, the concrete height rises at a speed of 5m / h, the conduit section length is 2.5m, the lowest section length is 4m, the lower end of the conduit is 500mm from the bottom, the conduit spacing is 3m, the conduit is 1.5m away from the end of the first slot section and the second slot section, and the concrete surface height difference at the two conduits is 0.3m.

[0061] Example 4

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

[0063] like Figure 2 , 3 As shown, a first slide groove 11 is provided in the middle of the fixed track 1, a second slide groove 12 is provided at the top of the fixed track 1, a driving motor 3 is slidably connected to the second slide groove 12 of a fixed track 1 located in the front, a first slider 4 is slidably connected to the second slide groove 12 of a fixed track 1 located in the rear, the driving motor 3 and the first slider 4 are connected to each other through a fixed rod 5, the right side of the fixed rod 5 is fixedly connected to the top of the telescopic upright 2, an extension rod 21 is provided at the bottom of the telescopic upright 2, a roller 22 is provided at the bottom of the extension rod 21, a rotating motor 6 is provided at the front and rear sides of the bottom of the telescopic upright 2, three connecting rods 61 are provided at equal intervals in the circumferential direction at the end of the output shaft of the rotating motor 6, and a scraper 62 for cleaning the groove wall of the continuous wall is provided at the end of the connecting rod 61;

[0064] like Figures 7 to 11As shown, a telescopic slurry guide pipe 7 is fixedly provided on the right side of the telescopic upright 2, and a telescopic bent pipe 8 is provided at the bottom of the telescopic slurry guide pipe 7. The upper vertical section of the telescopic bent pipe 8 is slidably connected with the bottom of the telescopic slurry guide pipe 7 and extends to the inside of the telescopic slurry guide pipe 7. The lower bending section of the telescopic bent pipe 8 faces the right side. Limit push rods 81 are symmetrically provided on both sides of the lower part of the vertical section of the telescopic bent pipe 8. The limit push rods 81 are docked with the scraper 62 in the rotating state to lift the telescopic bent pipe 8 to move upward. A slurry inlet pipe 71 is provided on the top of the telescopic slurry guide pipe 7. The bottom of the slurry 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 slurry guide pipe 7 is fixedly connected to the right side wall of the top of the telescopic upright 2 through a first buckle 73. The bottom of the telescopic slurry guide pipe 7 is fixedly connected to the right side wall of the bottom of the telescopic upright rod 2 through the second buckle 74. There are three scrapers 62 on one rotating motor 6. The end of the limit push rod 81 is provided with a groove 82 for docking with the scraper 62. The top of the telescopic elbow 8 is symmetrically provided with fifth sliders 83 on both sides. The two fifth sliders 83 are slidably connected with the fourth slide grooves 75 symmetrically provided on both sides of the inner wall of the bottom of the telescopic slurry guide pipe 7. The fourth slide groove 75 extends obliquely upward to make the telescopic elbow 8 rotate during the upward movement, so that when the telescopic elbow 8 moves up to a height of 20 cm, the scraper 62 and the groove 82 are disengaged and the telescopic elbow 8 is automatically reset under the action of gravity, completing the reciprocating up and down movement of the telescopic elbow 8;

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

[0066] At the same time, in step S2, when excavating the first trench section or the second trench section, the anti-collapse component is deployed when the overall excavation depth reaches 3.5m. Before deploying the anti-collapse component, an external mud pump is used to extract slurry, and the extracted mud is filtered through a vibrating screen to remove the debris, and then an external water supply pipe is used to replenish water and slurry. After the anti-collapse component is deployed, the telescopic slurry guide pipe 7 is used to extract mud, and then the mud is filtered through a vibrating screen to remove the debris, and then an external water supply pipe is used to replenish water and slurry.

[0067] Example 5

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

[0069] The fourth slide groove 75 extends obliquely upward and is used to make the telescopic bend 8 rotate during the upward movement, so that when the telescopic bend 8 moves up to a height of 15 cm, the scraper 62 and the groove 82 are disengaged and the telescopic bend 8 is automatically reset under the action of gravity, completing the reciprocating up and down movement of the telescopic bend 8;

[0070] At the same time, in step S2, when excavating the first trench section or the second trench section, the anti-collapse components are deployed when 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 slide groove 75 extends obliquely upward and is used to make the telescopic bend 8 rotate during the upward movement, so that when the telescopic bend 8 moves up to a height of 30 cm, the scraper 62 and the groove 82 are disengaged and the telescopic bend 8 is automatically reset under the action of gravity, completing the reciprocating up and down movement of the telescopic bend 8;

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

[0075] Working principle: The working principle of the anti-collapse assembly of the present invention is further explained below in combination with the method of the present invention.

[0076] When in use, when the first trench section or the second trench section is excavated in step S2 and reaches the specified depth, the anti-collapse assembly is installed. First, two fixed rails 1 are installed, and then other structural members are installed. The telescopic vertical rod 2 and the telescopic slurry guide pipe 7 are extended, so that the roller 22 contacts the bottom of the trench and can roll. When the grab bucket continuously grabs soil and moves, it is necessary to turn on the drive motor 3 to make the entire anti-collapse assembly move with the grab bucket. The drive wheel disc 31 drives the gear shaft 32 to rotate under the meshing action, so that it moves inside the tooth groove 111, and then drives the positioning rod 33, the first slider 4 and the fixed rod 5 to move, so as to realize the movement of the telescopic vertical rod 2 and the telescopic slurry guide pipe 7;

[0077] After clarifying the movement mode of the anti-collapse component, let's look at the working principle of sucking mud. First, connect the mud inlet pipe 71 to the mud pump and the vibrating screen. After it is turned on, the mud at the bottom of the groove is sucked through the telescopic slurry guide pipe 7 and the telescopic elbow 8. At this time, if the mud is sucked in one position all the time, it is easy to cause the groove wall to collapse. Therefore, it is necessary to make the inlet of the telescopic elbow 8 active. Then, turn on the rotating motor 6 to drive the connecting rod 61 and each scraper 62 to rotate. While cleaning the groove wall, when the scraper 62 passes through the groove 82 of the limit push rod 81, the groove 82 and the limit push rod are lifted upward, so that the top of the telescopic elbow 8 slides into the bottom of the telescopic slurry guide pipe 7 to achieve upward lifting. Figure 8 The state changes to Fig. 9 Medium state;

[0078] at the same time, Fig.11 We can see that the fourth slide groove 75 is an inclined section, so that the fifth slider 83 can turn while sliding along the fourth slide groove 75, which is manifested in the telescopic elbow 8 to achieve self-rotation, so that it can turn a certain angle during the upward movement, so that the limit push rod 81 can leave the rotation range of the scraper 62 in the vertical direction, so that the telescopic elbow 8 can automatically descend and reset under the action of gravity, and it also avoids the scraper 62 constantly lifting the limit push rod 81 to cause stress bending, and finally, the two functions of cleaning the groove wall and the mud inlet activity are realized simultaneously, and no additional power source is set.

[0079] It should be noted that the two groups of scrapers 62 on both sides always maintain cross-operation during the rotation process, that is, after a scraper 62 on the front side completes a contact cycle with the limit push rod 81 on the front side, the telescopic bend 8 will completely move down and reset, and then a scraper 62 on the rear side will contact the limit push rod 81 on the rear side to maintain a stable up and down movement cycle.

Claims

1. A construction method for preventing trench wall collapse from underground continuous wall in soft soil area, characterized in that: The following steps are involved: S1. Guide wall construction: excavate the guide wall around the edge of the foundation pit to be excavated, with a width of 1 to 1.2 m and a depth of 1.8 to 2.5 m. After draining the water in the guide wall pit, formwork is erected and concrete is poured. A concrete cushion layer is provided at the base of the guide wall; S2. Continuous wall trenching construction: A grab trenching machine is used to excavate the continuous wall inside the guide wall. The continuous wall is divided into the first trench section and the second trench section. After excavating a first trench section, a second trench section is separated in the middle to excavate the next first trench section. After the excavation of the two first trench sections is completed, the middle second trench section is excavated. The width of the first trench section and the second trench section is 80 to 90 cm. The length of the first trench section and the second trench section is the same. When excavating the first trench section and the second trench section, an anti-collapse component is used to clean the trench wall and replenish mud. The mud liquid level is 0.5 to 0.7 m higher than the groundwater level. After all the first trench sections and the second trench sections are excavated, a continuous wall trench is formed; S3, continuous wall pouring: hoist the steel cage to the continuous wall slot, and pour concrete within 4 hours after all the steel cages are hoisted to the continuous wall slot. Install two concrete pipes in the steel cage in each first slot section or second slot section, and inject concrete into the pipes. The bottom of the pipe is buried 2 to 4 meters below the concrete surface, and the concrete height rise speed is 3 to 5 m / h; S4. Foundation pit excavation: Use an excavator to excavate the foundation pit inside the continuous wall.

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

3. The construction method for preventing trench wall collapse from underground continuous wall in soft soil area according to claim 1, characterized in that: The conduit section length in step S3 is 2.5m, the lowest section length is 4m, the lower end of the conduit is 300-500mm from the bottom, the conduit spacing is 3m, the conduit is 1.5m away from the ends of the first and second trough sections, and the height difference of the concrete surface at the two conduits is no more than 0.3m.

4. The construction method for preventing trench wall collapse from underground continuous wall in soft soil area according to claim 1, characterized in that: The anti-collapse assembly in step S2 comprises fixed rails (1) located on both sides of the guide wall, and a telescopic vertical rod (2) located between the two fixed rails (1); A first slide groove (11) is provided in the middle of the fixed rail (1), a second slide groove (12) is provided at the top of the fixed rail (1), a driving motor (3) is slidably connected to the second slide groove (12) of a fixed rail (1) located in the front, a first slider (4) is slidably connected to the second slide groove (12) of a fixed rail (1) located in the rear, the driving motor (3) and the first slider (4) are connected to each other through a fixed rod (5), the right side of the fixed rod (5) is fixedly connected to the top of the telescopic vertical rod (2), an extension rod (21) is provided at the bottom of the telescopic vertical rod (2), a roller (22) is provided at the bottom of the extension rod (21), a rotating motor (6) is provided at the front and rear sides of the bottom of the telescopic vertical rod (2), a plurality of connecting rods (61) are provided at equal intervals at the end of the output shaft of the rotating motor (6), and a scraper (62) for cleaning the groove wall of the continuous wall is provided at the end of the connecting rod (61); A telescopic slurry guide pipe (7) is fixedly provided on the right side of the telescopic upright rod (2), a telescopic bent pipe (8) is provided at the bottom of the telescopic slurry guide pipe (7), an upper vertical section of the telescopic bent pipe (8) is slidably connected to the bottom of the telescopic slurry guide pipe (7) and extends into the interior of the telescopic slurry guide pipe (7), a lower bent section of the telescopic bent pipe (8) faces the right side, and limiting push rods (81) are symmetrically provided on both sides of the lower part of the vertical section of the telescopic bent pipe (8), the limiting push rods (81) are docked with the scraper (62) in a rotating state to lift the telescopic bent pipe (8) upward.

5. The construction method for preventing trench wall collapse from underground continuous wall in soft soil area according to claim 4, characterized in that: The front output end of the driving motor (3) is provided with a driving wheel disc (31), and a gear shaft (32) is meshedly connected below the driving wheel disc (31). The gear shaft (32) is meshedly connected with a tooth groove (111) provided on the lower surface of the first slide groove (11) of the fixed track (1) located in the 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 sliding block (4), and the top of the positioning rod (33) is fixedly connected to the bottom of the fixed rod (5) through a plurality of fixing blocks (51). 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 driving motor (3) is slidably connected to the third slide groove (13) of a fixed track (1) located in the front through a 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 in the rear through a third slider (42); and the first slider (4) below the corresponding limiting groove (41) is slidably connected to the first slide groove (11) of a fixed track (1) located in the rear.

6. The construction method for preventing trench wall collapse from underground continuous wall in soft soil area according to claim 5, characterized in that: A slurry inlet pipe (71) is provided at the top of the telescopic slurry guide pipe (7), and the bottom of the slurry inlet pipe (71) is slidably connected to the third sliding groove (13) of a fixed track (1) located at the rear through a fourth sliding block (72).

7. The construction method for preventing trench wall collapse from underground continuous wall in soft soil area according to claim 4, characterized in that: The top of the telescopic slurry guide pipe (7) is fixedly connected to the right side wall of the top of the telescopic upright pole (2) via a first buckle (73), and the bottom of the telescopic slurry guide pipe (7) is fixedly connected to the right side wall of the bottom of the telescopic upright pole (2) via a second buckle (74).

8. The construction method for preventing trench wall collapse from underground continuous wall in soft soil area according to claim 4, characterized in that: There are three scrapers (62) on one rotating motor (6), and a groove (82) for docking with the scraper (62) is provided at the end of the limit push rod (81). Fifth sliding blocks (83) are symmetrically provided on both sides of the top of the telescopic curved tube (8). The two fifth sliding blocks (83) are slidably connected to fourth sliding grooves (75) symmetrically provided on both sides of the inner wall of the bottom of the telescopic slurry guide tube (7) in a one-to-one corresponding manner. The fourth sliding groove (75) extends obliquely upward to enable the telescopic curved tube (8) to rotate during the upward movement, so that when the telescopic curved tube (8) moves up to a height of 15 to 30 cm, the scraper (62) and the groove (82) are disengaged, and the telescopic curved tube (8) is automatically reset under the action of gravity, completing the reciprocating up and down movement of the telescopic curved tube (8).

9. The construction method for preventing trench wall collapse from underground continuous wall in soft soil area according to claim 4, characterized in that: In step S2, when excavating the first trench section or the second trench section, the anti-collapse component is deployed after the overall excavation depth reaches 3 to 4 m. Before the anti-collapse component is deployed, an external mud pump is used to extract slurry, and the extracted slurry is filtered through a vibrating screen to remove the debris, and then an external water supply pipe is used to replenish water and slurry. After the anti-collapse component is deployed, the telescopic slurry guide pipe (7) is used to extract slurry, and then the debris is filtered through a vibrating screen to remove the debris, and then the external water supply pipe is used to replenish water and slurry.

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