A method for supporting a foundation pit in soft soil

Abstract

The application provides a soft soil geology foundation pit supporting method, and belongs to the field of foundation pit supporting, and comprises the following steps: S1, vertically setting a foundation pile mechanism on both sides of a foundation pit; S2, assembling both ends of a guard plate mechanism and both sides of the foundation pile mechanism, the guard plate mechanism being formed by two supporting plates and being used as a group, a draining cavity being formed between the two supporting plates; S3, providing outward supporting force for the foundation pile mechanism on both sides through a supporting mechanism, both ends of the supporting mechanism being connected with the foundation pile mechanism through a hinged structure; S4, setting a drainage system, and draining accumulated water in time through the set drainage system; and S5, continuously deepening the foundation pit, and synchronously moving the foundation pile mechanism and the guard plate mechanism downward along with the deepening of the foundation pit, and if the top ends of the foundation pile mechanism and the guard plate mechanism are below the ground level when the foundation pit is continuously deepened, the foundation pit mechanism and the guard plate mechanism can be used in a stacked manner above the foundation pit mechanism and the guard plate mechanism, and the set supporting mechanism provides supporting force for the foundation pile mechanism on both sides, so that the supporting mechanism and the guard plate mechanism are effectively prevented from being extruded by soft soil and collapsing.

Description

Technical Field

[0001] This invention relates to the field of foundation pit support technology, and specifically to a method for foundation pit support in soft soil geology. Background Technology

[0002] Foundation pit support refers to the measures taken to support, reinforce, and protect the sidewalls and surrounding environment of a foundation pit to ensure the safety of underground structure construction and the surrounding environment. Traditional methods for soft soil geology primarily employ supported structures, cantilever structures, double-row pile retaining structures, gravity cement-soil walls, or combinations of different structural types. Supported structures are cumbersome to construct internal supports; cantilever structures are suitable for shallower foundation pits; double-row piles are suitable for foundation pits where dewatering or cutoff walls can be used, but supported structures are expensive. When using gravity cement-soil walls, the foundation pit depth should not exceed 7 meters, and the volume is large. In soft soil geology, traditional foundation pit support methods have certain limitations, mainly in terms of investment cost, the impact of groundwater on foundation pit stability, and ease of construction. Summary of the Invention

[0003] Traditional internal supports require external equipment such as hydraulic jacks to apply pre-force. However, this invention simplifies the construction process by using mechanical self-locking bolts for adjustment, providing a method for supporting foundation pits in soft soil. The foundation pile mechanism fixes both ends of the protective plate mechanism, and the protective plate structure blocks the soft soil on both sides of the foundation pit. The drainage cavity formed between the two protective plates allows water in the soft soil to drain smoothly, and the drainage system inside the drainage cavity effectively drains the water accumulated inside. The established support mechanism provides support to the foundation pile mechanism on both sides, effectively preventing the support mechanism and protective plate mechanism from collapsing due to pressure from the soft soil.

[0004] To solve the above problems, the present invention adopts the following technical solution: A method for supporting foundation pits in soft soil, the method comprising the following steps: S1: Vertically install foundation pile mechanisms on both sides of the foundation pit; S2: Assemble the protective plate mechanism. The two ends of the protective plate mechanism are assembled with the two sides of the foundation pile mechanism. The protective plate mechanism is composed of two support plates assembled into a set for use. A drainage cavity is formed between the two support plates. S3: Connecting support mechanism, the two ends of which are connected to the pile mechanism through a hinge structure to provide outward support force to the pile mechanism on both sides; S4: A drainage system is established to promptly extract and discharge accumulated water; S5: As the foundation pit deepens, the foundation pile mechanism and the protective plate mechanism move down synchronously. When the top of the foundation pile mechanism and the protective plate mechanism is lower than the ground level, and the foundation pit continues to deepen, a new set of foundation pile mechanism and protective plate mechanism is superimposed on top of the foundation pile mechanism and the protective plate mechanism.

[0005] Furthermore, in S1, the pile mechanism includes a pile, and guide grooves are provided on the left and right outer surfaces of the pile. A soil-breaking guide head is fixedly connected to the lower surface of the pile, and a connecting seat and a sliding groove are fixedly connected to the front surface of the pile.

[0006] Furthermore, in S2, the protective plate mechanism includes a protective plate, which includes a first protective plate and a second protective plate. The first protective plate is provided with drainage holes, and a reinforcing rib is fixedly connected to the inner surface of the first protective plate. The left and right ends of the first protective plate and the second protective plate are both connected to the guide groove.

[0007] Furthermore, in S3, the support mechanism includes a support frame, with a set of foundation piles and a protective plate combination structure connected to each end of the support frame, and two sets of support frames provided between the two sets of foundation piles and protective plate combination structures.

[0008] Furthermore, the support frame includes a fixed beam, the left end of which is hinged to a first support arm, the right end of which is hinged to a second support arm, and the ends of the first and second support arms away from the fixed beam are respectively hinged to connecting seats on both sides.

[0009] Furthermore, the outer surface of the fixed beam is threaded with bolts, one end of which is movably connected to a movable beam. The left end of the movable beam is movably connected to a first support arm, and the right end of the movable beam is movably connected to a second support arm.

[0010] Furthermore, the lower surface of the first support arm is hinged with a first diagonal brace, and the lower surface of the second support arm is hinged with a second diagonal brace. The other ends of the first and second diagonal braces are slidably connected to the sliding grooves on both sides, respectively.

[0011] Furthermore, a drainage cavity is formed between the first and second protective plates. A drainage pipe is fixedly connected to the side of the foundation pile near the drainage cavity. One end of the drainage pipe is connected to the drainage cavity, and the other end of the drainage pipe is connected to a water pump. A soil-breaking guide head is fixedly connected to the lower end face of the foundation pile.

[0012] Compared with existing technologies, the soft soil foundation pit support method of the present invention has the following advantages: (1) The pile structure is used to fix both ends of the retaining plate structure, and the retaining plate structure blocks the soft soil on both sides of the foundation pit. The double-layer retaining plate design not only enhances the overall rigidity, absorbs and disperses external pressure, and improves the durability and compressive strength of the system, but also allows the retaining plate to be reused multiple times, improving the utilization rate of the support structure and reducing investment costs.

[0013] (2) The drainage cavity formed between the two protective plates allows water in the soft soil to drain smoothly. The drainage system inside the drainage cavity effectively drains the water inside, reducing the risk of sudden surge and soil erosion, and improving the stability of the foundation pit.

[0014] (3) The support mechanism provides support for the pile mechanism on both sides, effectively preventing the support mechanism and the protective plate mechanism from collapsing due to soft soil compression. The mechanism is connected to the pile through a hinged structure, providing additional outward support for the pile, significantly reducing the risk of collapse due to soft soil compression. The pile mechanism and the protective plate mechanism can move down synchronously during the deepening of the foundation pit, and when further deepening is required, a new structure can be used by superimposing, making construction adjustments more convenient. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the soft soil foundation pit support method of the present invention; Figure 2 This is an overall structural diagram of the soft soil foundation pit support device of the present invention; Figure 3 This is a structural diagram of the support mechanism in the soft soil foundation pit support device of the present invention; Figure 4 This is a schematic diagram of the left side of the protective plate mechanism and the foundation pile mechanism of the soft soil foundation pit support device of the present invention; Figure 5 This is a schematic diagram of the right side of the protective plate mechanism and the foundation pile mechanism of the soft soil foundation pit support device of the present invention. Figure 6 This is a schematic diagram of the reinforcing bar structure of the soft soil foundation pit support device of the present invention.

[0017] In the diagram, 1-foundation pile; 101-guide channel; 102-connecting seat; 103-sliding channel; 104-drainage pipe; 105-soil breaking guide head; 2-protective plate; 201-first protective plate; 202-second protective plate; 203-drainage hole; 204-reinforcing rib; 3-support frame; 301-fixed beam; 302-bolt; 303-support arm one; 304-support arm two; 305-movable beam; 306-diagonal brace arm one; 307-diagonal brace arm two. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] This invention proposes a method for supporting foundation pits in soft soil, such as... Figure 1 As shown, it includes the following steps: S1: Vertically install foundation pile mechanisms on both sides of the foundation pit; S2: Assemble the protective plate mechanism. The two ends of the protective plate mechanism are assembled with the two sides of the foundation pile mechanism. The protective plate mechanism is composed of two support plates assembled into a set for use. A drainage cavity is formed between the two support plates. S3: Connecting support mechanism, the two ends of which are connected to the pile mechanism through a hinge structure to provide outward support force to the pile mechanism on both sides; S4: A drainage system is established to promptly extract and discharge accumulated water; S5: As the foundation pit deepens, the foundation pile mechanism and the protective plate mechanism move down synchronously. When the top of the foundation pile mechanism and the protective plate mechanism is lower than the ground level, and the foundation pit continues to deepen, a new set of foundation pile mechanism and protective plate mechanism is superimposed on top of the foundation pile mechanism and the protective plate mechanism.

[0020] like Figure 2-6 As shown, the specific structure of the soft soil foundation pit support device is as follows: In S1, the pile mechanism includes a pile 1. Guide grooves 101 are provided on the left and right outer surfaces of the pile 1. A soil breaking guide head 105 is fixedly connected to the lower surface of the pile 1. A connecting seat 102 and a sliding groove 103 are fixedly connected to the front surface of the pile 1.

[0021] In S2, the guard plate mechanism includes guard plate 2, which includes a first guard plate 201 and a second guard plate 202. The first guard plate 201 is provided with a drainage hole 203, and a reinforcing rib 204 is fixedly connected to the inner surface of the first guard plate 201. The left and right ends of the first guard plate 201 and the second guard plate 202 are connected to the guide groove 101.

[0022] A drainage cavity is formed between the first protective plate 201 and the second protective plate 202. A drainage pipe 104 is fixedly connected to the side of the foundation pile 1 near the drainage cavity. One end of the drainage pipe 104 is connected to the drainage cavity, and the other end of the drainage pipe 104 is connected to a water pump. A soil breaking guide head 105 is fixedly connected to the lower end face of the foundation pile 1.

[0023] In S3, the support mechanism includes a support frame 3. Each end of the support frame 3 is connected to a combination of foundation piles 1 and protective plates 2. Two sets of support frames 3 are positioned between the two sets of foundation piles 1 and protective plates 2. The support frame 3 includes a fixed beam 301. The left end of the fixed beam 301 is hinged to a first support arm 303, and the right end of the fixed beam 301 is hinged to a second support arm 304. The ends of the first and second supports 303 away from the fixed beam 301 are respectively hinged to connecting seats 102 on both sides. The hinged connection between the first and second supports 303 and the connecting seats 102 allows for rapid adjustment of the arm span to adapt to different pit sizes, improving the dynamic adaptability of the support structure.

[0024] The outer surface of the fixed beam 301 is threaded with bolts 302. One end of the bolts 302 is movably connected to a movable beam 305. The left end of the movable beam 305 is movably connected to support arm 303, and the right end of the movable beam 305 is movably connected to support arm 304. By driving the movable beam 305 up and down through the bolts 302 on the outer surface of the fixed beam, the support angles of support arm 303 and support arm 304 can be changed. The outward support force can be flexibly adjusted according to the width of the foundation pit to ensure that the pile structures on both sides are subjected to balanced forces.

[0025] The lower surface of support arm 1 (303) is hinged with diagonal brace arm 1 (306), and the lower surface of support arm 2 (304) is hinged with diagonal brace arm 2 (307). The other ends of diagonal brace arm 1 (306) and diagonal brace arm 2 (307) are slidably connected to the sliding grooves 103 on both sides, respectively. The diagonal brace arm 1 (306) and diagonal brace arm 2 (307) hinged to the lower surfaces of support arm 1 (303) and support arm 2 (304) are slidably connected to the foundation pile sliding grooves 103, forming a triangular stable structure that effectively disperses the lateral pressure of the soft soil and avoids support deformation.

[0026] In this support structure, the support mechanism, through the coordinated design of fixed beams, movable beams, and outriggers, distributes concentrated loads to the foundation piles, reducing the risk of localized stress concentration. The components of the support mechanism are rapidly assembled via hinged and sliding connections, simplifying the construction process and reducing on-site operational difficulty. The hinged design of the support structure minimizes the occupation of internal space in the foundation pit, increases the working height below, and facilitates the passage of construction equipment and personnel.

[0027] In this support structure, the pre-applied axial force is achieved through the linkage between bolt 302 and movable beam 305 in the support mechanism. The specific steps are as follows: Bolt rotation adjustment: Rotate the bolt 302 on the outer surface of the fixed beam 301 to drive the movable beam 305 to move in the vertical direction.

[0028] Support arm angle change: The two ends of the movable beam 305 are movably connected to support arm 1 303 and support arm 2 304 respectively. Its up and down movement will push the support arm to rotate around the hinge point, changing the support angle.

[0029] Axial force is transmitted to the pile: Support arms one and two are hinged to pile 1 through connecting seat 102. When the angle changes, an outward horizontal thrust is applied to the pile, forming a pre-applied axial force.

[0030] Working principle: During use, two foundation piles 1 are installed on both sides of the foundation pit. The first protective plate 201 is installed in the groove 103 on the foundation pile 1 near the pit wall. The second protective plate 202 is installed in the groove 103 on the outer side. The foundation piles 1 on both sides of the foundation pit are aligned. The support frame 3 is installed between the two sets of foundation piles 1. The first support arm 303 on the support frame 3 is installed on the foundation pile 1 on one side through the connecting seat 102. The second support arm 304 on the support frame 3 is installed on the foundation pile 1 on the other side through the connecting seat 102. The first diagonal brace 306 installed on the first support arm 303 and the second diagonal brace 307 installed on the second support arm 304 are installed in the groove 103 at the corresponding positions. The movable beam 305 is moved by the bolts 302 on the fixed beam 301 installed on the support frame 3, so that the first support arm 303 and the second support arm 304 can move. A drainage pipe 104 is installed on the outer surface of the foundation pile 1. The end of the drainage pipe 104 is connected to the drainage cavity formed between the first protective plate 201 and the second protective plate 202. A water pump is installed at the other end of the drainage pipe 104 to pump out the water accumulated in the drainage cavity in a timely manner.

[0031] Compared with traditional methods, this invention achieves water interception through a collaborative design of "drainage cavity + drainage system," enabling proactive control of seepage problems in soft soil foundation pits and effectively reducing the risk of pit collapse caused by water accumulation. Specifically, it includes the following improvements: (1) Active drainage mechanism: The drainage cavity formed by the protective plate mechanism collects seepage water and actively pumps it out through the drainage system to avoid water accumulation.

[0032] (2) Modular support structure: The pile structure and the protective plate structure can be disassembled and assembled, and can be moved down or superimposed synchronously as the foundation pit deepens, adapting to dynamic construction needs.

[0033] (3) Adjustable support system: The outward support force is provided by the articulated support mechanism, and the stability is enhanced by the diagonal bracing arm to avoid structural collapse caused by soft soil compression.

[0034] Specifically, this includes the following key steps and structural coordination: (1) Moisture collection: the synergistic effect of the drainage cavity and drainage holes.

[0035] ① Double-layer design of the guard plate mechanism: The guard plate mechanism consists of a first guard plate 201 and a second guard plate 202, with an independent drainage cavity formed between the two guard plates.

[0036] ② Drainage hole permeation guidance: The outer surface of the first protective plate 201 is provided with drainage holes 203. Water accumulated in the soft soil layer permeates into the drainage cavity through the drainage holes, realizing the initial isolation and collection of water on the side wall of the foundation pit.

[0037] (2) Water drainage: Active pumping mechanism of drainage system.

[0038] ① Drainage pipe connected to the drainage cavity: Drainage pipe 104 is fixedly connected to the side of the foundation pile 1 near the drainage cavity. One end of the pipe is directly connected to the drainage cavity, and the other end is connected to a water pump.

[0039] ②Active drainage control: The water collected in the drainage cavity is promptly pumped out of the foundation pit by a water pump to prevent water from accumulating in the cavity, which could lead to increased pressure or seep back into the foundation pit.

[0040] (3) Structural sealing: the fixed connection between the protective plate and the foundation pile.

[0041] ①Guide groove fixing plate: Guide grooves 101 are provided on the outer surfaces of the left and right sides of the foundation pile 1. The two ends of the first guard plate 201 and the second guard plate 202 are inserted into the guide grooves to form a sealed connection to prevent moisture from seeping through the gap between the guard plate and the foundation pile.

[0042] ② Reinforcing ribs enhance structural stability: Reinforcing ribs 204 are fixedly connected to the inner surface of the first protective plate 201 to improve the deformation resistance of the protective plate and prevent water seepage caused by the expansion of gaps in the protective plate due to soft soil compression.

[0043] ③ Combining active and passive methods: Water is passively collected through drainage holes and then actively discharged through a water pump, forming a closed loop of "collection-discharge" to solve the problem of the passive water interception defect of traditional support that relies solely on water-stop curtains.

[0044] ④ Dynamically adapts to deepening of the foundation pit: As the foundation pit deepens, the protective plate mechanism can be moved down or superimposed to ensure that the water interception system always covers the entire side wall of the foundation pit, avoiding the risk of water seepage due to insufficient support height.

[0045] The present invention has been described in detail above through embodiments, but the content is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A method for supporting foundation pits in soft soil, characterized in that: The method includes the following steps: S1: Vertically install foundation pile mechanisms on both sides of the foundation pit; S2: Assemble the protective plate mechanism. The two ends of the protective plate mechanism are assembled with the two sides of the foundation pile mechanism. The protective plate mechanism is composed of two support plates assembled into a set for use. A drainage cavity is formed between the two support plates. S3: Connecting support mechanism, the two ends of which are connected to the pile mechanism through a hinge structure to provide outward support force to the pile mechanism on both sides; S4: A drainage system is established to promptly extract and discharge accumulated water; S5: As the foundation pit deepens, the foundation pile mechanism and the protective plate mechanism move down synchronously. When the top of the foundation pile mechanism and the protective plate mechanism is lower than the ground level, and the foundation pit continues to deepen, a new set of foundation pile mechanism and protective plate mechanism is superimposed on top of the foundation pile mechanism and the protective plate mechanism.

2. The method for supporting foundation pits in soft soil according to claim 1, characterized in that: In S1, the pile structure includes a pile (1), and guide grooves (101) are provided on both outer surfaces of the pile (1). A soil breaking guide head (105) is fixedly connected to the lower surface of the pile (1), and a connecting seat (102) and a sliding groove (103) are fixedly connected to the front surface of the pile (1).

3. The method for supporting foundation pits in soft soil according to claim 2, characterized in that: In S2, the guard plate mechanism includes a guard plate (2), the guard plate (2) includes a first guard plate (201) and a second guard plate (202), the first guard plate (201) is provided with a drain hole (203), the inner surface of the first guard plate (201) is fixedly connected with a reinforcing rib (204), and the left and right ends of the first guard plate (201) and the second guard plate (202) are both connected to the guide groove (101).

4. The method for supporting foundation pits in soft soil according to claim 3, characterized in that: In S3, the support mechanism includes a support frame (3), and the two ends of the support frame (3) are respectively connected to a set of pile (1) and guard plate (2) combination structure, and two sets of support frames (3) are provided between the two sets of pile (1) and guard plate (2) combination structures.

5. A method for supporting foundation pits in soft soil according to claim 4, characterized in that: The support frame (3) includes a fixed beam (301), the left end of which is hinged to a first support arm (303), the right end of which is hinged to a second support arm (304), and the ends of the first support arm (303) and the second support arm (304) away from the fixed beam (301) are respectively hinged to connecting seats (102) on both sides.

6. The method for supporting foundation pits in soft soil according to claim 5, characterized in that: The outer surface of the fixed beam (301) is threaded with a bolt (302), one end of which is movably connected to a movable beam (305). The left end of the movable beam (305) is movably connected to a first support arm (303), and the right end of the movable beam (305) is movably connected to a second support arm (304).

7. A method for supporting foundation pits in soft soil according to claim 6, characterized in that: The lower surface of the first support arm (303) is hinged with a first diagonal brace arm (306), and the lower surface of the second support arm (304) is hinged with a second diagonal brace arm (307). The other ends of the first diagonal brace arm (306) and the second diagonal brace arm (307) are slidably connected to the sliding grooves (103) on both sides respectively.

8. A method for supporting foundation pits in soft soil according to claim 3, characterized in that: A drainage cavity is formed between the first protective plate (201) and the second protective plate (202). A drainage pipe (104) is fixedly connected to the side of the foundation pile (1) near the drainage cavity. One end of the drainage pipe (104) is connected to the drainage cavity, and the other end of the drainage pipe (104) is connected to a water pump. A soil breaking guide (105) is fixedly connected to the lower end face of the foundation pile (1).

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