A foundation pit support structure under complex conditions and its construction method

Abstract

This invention relates to a foundation pit support structure and its construction method under complex conditions, comprising a foundation pit; hollow anchor rods anchored within the foundation pit; an inner concrete mesh disposed inside the foundation pit and connected to the inner end of the anchor rods; firstly, soft soil is cut with a steel wire rope and moved to the inner end of two adjacent anchor rods inside the sidewall of the foundation pit; then, a hole is enlarged between the inner ends of the two anchor rods using a drill bit; finally, concrete is poured into the path between the inner ends of the two anchor rods using the hollow anchor rods to form an inner concrete mesh, thereby improving the protective effect of the anchor rods on the foundation pit.

Description

Technical Field

[0001] This invention relates to a foundation pit support structure and its construction method under complex conditions, belonging to the field of building construction technology. Background Technology

[0002] During the construction of building foundations and underground structures, it is usually necessary to excavate foundation pits. In order to ensure the safety of the surrounding environment of the foundation pit, it is necessary to support and protect the side walls of the foundation pit and the surrounding environment.

[0003] For example, CN207794091U describes a soil nail and anchor combined support for a foundation pit, comprising soil nails fixed on the slope of the foundation pit and anchor rods anchored in the slope. A steel mesh is installed on the slope, extending downwards to a cushion layer and welded to the transverse reinforcing steel bars. The soil nails and anchor rods work together to reinforce the foundation pit, and the steel bars in the slope's shotcrete layer extend towards the bottom of the pit, improving the integrity of the foundation pit and its bottom, and enhancing the support performance of the foundation pit.

[0004] However, when the steel mesh is placed on the slope of the foundation pit, the contact area between the anchor bolt and the foundation pit is small, which makes the protective effect less than ideal, especially when the soil near the foundation pit is soft. Summary of the Invention

[0005] The purpose of this invention is to provide a foundation pit support structure and its construction method under complex conditions, so as to solve the problems mentioned in the background art.

[0006] The technical solution of the present invention is as follows:

[0007] A foundation pit support structure under complex conditions includes:

[0008] Foundation pit;

[0009] Anchor rod, the anchor rod is hollow and anchored in the foundation pit;

[0010] An inner concrete mesh is installed inside the sidewall of the foundation pit and connected to the inner end of the anchor rod.

[0011] Preferably, it also includes an external reinforced concrete mesh, which is disposed on the outer wall of the foundation pit, and the outer end of the anchor rod is connected to the external reinforced concrete mesh.

[0012] Preferably, the device also includes a wire rope and a traction machine, wherein the wire rope passes through at least two anchor rods and its two ends are connected to two sets of traction machines respectively.

[0013] Preferably, a guide wheel is installed inside the anchor rod near its inner end.

[0014] Preferably, the outer wall of the wire rope is fitted with a drill bit with a variable diameter structure.

[0015] Preferably, the drill bit includes a fixed seat fixed to the outer wall of the wire rope and a movable seat movably disposed on the outer side of the wire rope. The fixed seat is hinged with a plurality of upper connecting rods in a circular array, and the movable seat is hinged with a plurality of lower connecting rods in a circular array. The upper connecting rods and the lower connecting rods are hinged in a one-to-one correspondence, and the fixed seat and the movable seat are engaged in a snap-fit ​​connection.

[0016] Preferably, the fixed seat and the movable seat are engaged in a one-way snap-fit ​​connection via a snap-fit ​​component and a snap-fit ​​groove.

[0017] Preferably, the end of the movable seat is provided with a one-way component of an elastic structure, which is used to pass through the inside of the anchor rod in one direction.

[0018] Preferably, the upper or lower connecting rod comprises a plurality of hinged units that are sequentially hinged end to end, and the rotation angle between any two adjacent hinged units is within 10°.

[0019] A construction method for a foundation pit support structure under complex conditions includes the following steps:

[0020] Thread the steel wire rope into the two sets of anchor rods;

[0021] Anchor the anchor rods inside the foundation pit;

[0022] The two ends of the wire rope are respectively installed on two sets of traction machines, and the two sets of traction machines work together to drive the wire rope to cut the soil in the foundation pit;

[0023] A drill bit is installed on a steel wire rope. Two sets of traction machines work together to drive the steel wire rope back and forth. During this process, the drill bit expands the diameter and forms the trajectory of the inner concrete mesh.

[0024] Concrete is poured along the trajectory of the inner cavity of the anchor rod to expand the diameter of the drill bit, forming an inner concrete mesh.

[0025] The present invention has the following beneficial effects:

[0026] First, the softer soil is cut with a steel wire rope and moved to the inner end of two adjacent anchor rods inside the side wall of the foundation pit. Then, the hole between the inner ends of the two anchor rods is enlarged with a drill bit. After that, the hollow structure of the anchor rod is used to pour concrete into the path between the inner ends of the two anchor rods to form an inner concrete mesh, thereby improving the protective effect of the anchor rods on the foundation pit. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention;

[0028] Figure 2 This is a schematic diagram showing the cooperation between the traction machine, wire rope, and anchor rod of the present invention;

[0029] Figure 3 This is a schematic diagram of the steel wire rope passing through the inside of the anchor rod according to the present invention;

[0030] Figure 4 This is a schematic diagram of the three-dimensional structure of the drill bit of the present invention;

[0031] Figure 5 This is a cross-sectional view of the drill bit of the present invention;

[0032] Figure 6 This is a schematic diagram of the upper / lower connecting rod structure of the present invention.

[0033] The reference numerals in the figure are as follows:

[0034] 1. Excavation pit; 2. Anchor rod; 21. Guide wheel; 3. Outer reinforced concrete mesh; 4. Inner concrete mesh; 5. Steel wire rope; 6. Traction machine; 8. Drill bit; 81. Fixed seat; 811. Clip-on component; 82. Movable seat; 821. Clip-on groove; 822. One-way component; 83. Upper connecting rod; 84. Lower connecting rod; 85. Protective cloth; 86. Slotting; 800. Hinge unit. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0036] Example 1: As Figure 1-5 As shown:

[0037] First, the steel wire rope 5 is inserted from the outer end of the anchor rod 2 into the interior of the anchor rod 2 and then out through its inner end. Then, it is inserted from the inner end of another anchor rod 2 into the interior of the anchor rod 2 and out through its outer end. Next, multiple sets of anchor rods 2 are evenly anchored and fixed inside the side wall of the pit 1. Then, a reinforced concrete mesh 3 is laid on the side wall of the pit 1 and solidified, so that the outer ends of the anchor rods 2 are fixed to the reinforced concrete mesh 3. At this point, most of the steel wire rope 5 is outside the pit 1.

[0038] Then, the two ends of the wire rope 5 are connected to two traction machines 6. The two traction machines 6 keep the wire rope 5 taut and work in opposite directions, causing the wire rope 5 to move back and forth. Since the soil on the side wall of the pit 1 is relatively soft, the back-and-forth movement of the wire rope 5 cuts the soil until the wire rope 5 moves relatively between the inner ends of the two sets of anchor rods 2. At this point, the state is as follows: Figure 2 As shown. Wire rope 5 is relatively thin.

[0039] like Figure 3 As shown, a guide wheel 21 is installed near the inner end of the inner cavity of the anchor rod 2. A through groove is provided extending outward from the inner end of the anchor rod 2. The direction of extension of this through groove is opposite to the direction in which the anchor rod 2 is inserted into the soil and is at an obtuse angle to prevent the soil from being embedded in the through groove when the anchor rod 2 is inserted into the soil. This through groove is used for the steel wire rope 5 and the drill bit 8 to pass through.

[0040] like Figure 4-5 As shown, the drill bit 8 includes a fixed seat 81, a movable seat 82, an upper connecting rod 83, a lower connecting rod 84, and a protective cloth 85. A through hole is provided at the center of the fixed seat 81 and the movable seat 82 for the steel wire rope 5 to pass through. Several upper connecting rods 83 are arranged in a ring and their upper ends are hinged to the fixed seat 81. Several lower connecting rods 84 are arranged in a ring and their lower ends are hinged to the movable seat 82. The lower ends of the upper connecting rods 83 and the upper ends of the lower connecting rods 84 are hinged and correspond to each other. A snap-fit ​​component 811 is provided on the lower surface of the fixed seat 81, with the end of the snap-fit ​​component 811 having a triangular hook structure. An "L"-shaped snap-fit ​​groove 821 is provided on the upper surface of the movable seat 82. A flexible protective cloth 85 is provided between two adjacent sets of upper connecting rods 83 and two sets of lower connecting rods 84 to prevent external soil from entering the snap-fit ​​groove 821. The outer diameters of the fixed seat 81 and the movable seat 82 are slightly smaller than the inner diameter of the slot. A one-way component 822 with a conical structure is fixedly installed on the outer side of the movable seat 82. The one-way component 822 is made of elastic material, and the end of the one-way component 822 with a larger outer diameter is larger than the inner diameter of the slot.

[0041] The fixed seat 81 is fixed to the outer wall of the wire rope 5, and the movable seat 82 is relatively movably sleeved on the outside of the wire rope 5. At this time, several upper connecting rods 83 and several lower connecting rods 84 are attached to the outer wall of the wire rope 5. Then the traction machine 6 drives the wire rope 5 to move. During this process, the drill bit 8 is driven to insert into the inside of the anchor rod 2. During this process, the fixed seat 81 is located in front of the movable seat 82. Until both the fixed seat 81 and the movable seat 82 pass through the through groove at the inner end of the anchor rod 2, during this process, the smaller end of the elastic material and the one-way component 822 with a conical structure passes through the through groove first to achieve one-way passage.

[0042] Then, the traction machine 6 drives the wire rope 5 to move in the opposite direction. During this process, since the one-way component 822 cannot pass through the through slot in the opposite direction, the fixed seat 81 approaches the movable seat 82, so that the snap-fit ​​component 811 snaps into the snap-fit ​​slot 821 in one direction, thus fixing the fixed seat 81 and the movable seat 82 into one unit. During this process, the upper connecting rod 83 and the lower connecting rod 84 rotate accordingly. Finally, the upper connecting rod 83 and the lower connecting rod 84 are approximately perpendicular to the fixed seat 81 / movable seat 82. The diameter of the drill bit 8 is changed by rotating several upper connecting rods 83 and the lower connecting rod 84.

[0043] Then, the two sets of traction machines 6 drive the steel wire rope 5 to move back and forth. The steel wire rope 5 drives the drill bit 8, whose outer diameter has increased, to move back and forth, drilling and expanding the diameter of the soil between the inner ends of the two adjacent sets of anchor rods 2, so that the outer diameter of the steel wire rope 5 between the inner ends of the two adjacent sets of anchor rods 2 is expanded to form an inner concrete net track.

[0044] Then, concrete is poured and pressurized into the inner cavity of the hollow anchor rod 2. The concrete flows through the inner cavity of the anchor rod 2 and through the groove to the inner concrete mesh trajectory. The above steps are repeated, and concrete is poured between each pair of the inner ends of multiple anchor rods 2 to form an inner concrete mesh 4. The inside of the anchor rod 2 is filled with concrete to increase its strength.

[0045] As the wire rope 5 moves back and forth, it rotates irregularly, causing the drill bit 8 to rotate accordingly, which is beneficial for hole enlargement; furthermore, the expanded protective cloth 85 follows and cooperates in drilling / enlarging.

[0046] Example 2: An improvement on Example 1, the difference being:

[0047] like Figure 2 As shown, since the trajectory of the steel wire rope 5 has a bend, the guide wheel 21 inside the anchor rod 2 is used to guide the steel wire rope 5 to turn, so as to avoid friction between the steel wire rope 5 and the anchor rod 2 during the back and forth movement.

[0048] like Figure 6 As shown, the upper connecting rod 83 and / or the lower connecting rod 84 include a plurality of hinge units 800 that are hinged end to end in sequence. The head of the hinge unit 800 is hinged to the tail of another set of hinge units 800, and the rotation angle between any two adjacent hinge units 800 is between 0-10° (the angle is small). Furthermore, different models of hinge units 800 can be selected according to requirements, so that the rotation angle between two adjacent sets of hinge units 800 is adjustable.

[0049] This makes the upper link 83 and the lower link 84 deformable structures, which can adjust the angle within a certain range to facilitate steering.

[0050] like Figure 4 As shown, the fixed seat 81 and the movable seat 82 have slots 86 formed from the edge towards the center of the through hole. These slots 86 allow the wire rope 5 to be placed opposite each other in the fixed seat 81 and the movable seat 82 without being removed from the traction machine 6. The wire rope 5 is then fixed to the fixed seat 81 with fastening screws, and a limiting screw prevents the wire rope 5 from dislodging from the through hole of the movable seat 82. One of the protective sheets 85 has a clearance groove for the wire rope 5 to pass through.

[0051] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A construction method for a foundation pit support structure under complex conditions, characterized in that, include: Foundation pit (1); Anchor rod (2), the anchor rod (2) is hollow and anchored in the foundation pit (1); An inner concrete mesh (4) is provided inside the side wall of the foundation pit (1) and connected to the inner end of the anchor rod (2); It also includes a wire rope (5) and a traction machine (6), wherein the wire rope (5) passes through at least two anchor rods (2) and the two ends of the wire rope (5) are respectively connected to two sets of traction machines (6); The outer wall of the wire rope (5) is fitted with a drill bit (8) with a variable diameter structure. Includes the following steps: Insert the steel wire rope (5) into the two sets of anchor rods (2); Anchor rod (2) is anchored inside the foundation pit (1); The two ends of the wire rope (5) are respectively installed on two sets of traction machines (6), and the two sets of traction machines (6) work together to drive the wire rope (5) to cut the soil of the pit (1); A drill bit (8) is installed on the wire rope (5). Two sets of traction machines (6) work together to drive the wire rope (5) to move back and forth. During this process, the drill bit (8) expands the diameter to form the trajectory of the inner concrete net (4). Concrete is poured along the trajectory of the inner cavity of the anchor rod (2) to expand the diameter of the drill bit (8) to form the inner concrete mesh (4), thus forming the inner concrete mesh (4).

2. The construction method for a foundation pit support structure under complex conditions as described in claim 1, characterized in that: It also includes an outer reinforced concrete mesh (3), which is set on the outer wall of the foundation pit (1), and the outer end of the anchor rod (2) is connected to the outer reinforced concrete mesh (3).

3. The construction method for a foundation pit support structure under complex conditions as described in claim 2, characterized in that: The anchor rod (2) has a guide wheel (21) installed inside near the inner end.

4. The construction method for a foundation pit support structure under complex conditions as described in claim 2, characterized in that: The drill bit (8) includes a fixed seat (81) fixed to the outer wall of the wire rope (5) and a movable seat (82) movably disposed on the outer side of the wire rope (5). The fixed seat (81) is hinged with a plurality of upper connecting rods (83) in a ring array, and the movable seat (82) is hinged with a plurality of lower connecting rods (84) in a ring array. The upper connecting rods (83) and the lower connecting rods (84) are hinged in a one-to-one correspondence, and the fixed seat (81) and the movable seat (82) are engaged in a snap-fit ​​engagement.

5. The construction method for a foundation pit support structure under complex conditions as described in claim 4, characterized in that: The fixed seat (81) and the movable seat (82) are engaged in a one-way snap-fit ​​connection via a snap-fit ​​member (811) and a snap-fit ​​groove (821).

6. The construction method for a foundation pit support structure under complex conditions as described in claim 5, characterized in that: The end of the movable seat (82) is provided with a one-way member (822) with an elastic structure, and the one-way member (822) at the end of the movable seat (82) is used to pass through the inside of the anchor rod (2) in one direction.

7. The construction method for a foundation pit support structure under complex conditions as described in claim 4, characterized in that: The upper link (83) or lower link (84) includes a plurality of hinge units (800) that are hinged end to end in sequence, and the rotation angle between any two adjacent hinge units (800) is within 10°.

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