An active deformation control anchor structure for a foundation pit

Abstract

This utility model discloses an active deformation control anchor cable structure for foundation pits. The active deformation control anchor cable structure includes an arrowhead, a barb assembly for the arrow shaft, and a sealing element. The arrow shaft is installed in the corresponding anchor cable mounting hole on the side wall of the foundation pit waler via the sealing element. The two ends of the arrow shaft are respectively positioned inside and outside the foundation pit waler. The arrowhead is fixedly connected to the end of the arrow shaft positioned outside the foundation pit waler. Multiple barb assemblies are arranged sequentially and at intervals along the axial direction of the arrow shaft outside the arrow shaft between the side wall of the foundation pit waler and the arrowhead. The anchor cable structure proposed in this utility model can resist the lateral deformation of the undisturbed soil, making construction more convenient, and can also be asymmetrically arranged according to the depth of the waler.

Description

Technical Field

[0001] This utility model relates to an anchor cable structure in the field of foundation pit retaining construction, specifically to an active deformation control anchor cable structure for foundation pits. Background Technology

[0002] Traditional small-scale foundation pit retaining structures often employ cantilever support to ensure sufficient working face for excavation. When the excavation depth is deep or the soil conditions are weak, a combination of cantilever support structures and other support methods is typically used in the design and construction of the retaining structure. For example, the SMW method (or other cantilever support structures, but SMW is used as an example here) generally works in conjunction with anchor cables to resist the lateral forces from the unexcavated soil into the foundation pit. When using prestressed anchor cables, excessive redundancy in the anchor cable design not only increases the risk of anchor cable overload failure but also increases support costs. Conversely, if the anchor cables are designed to operate close to their limit, it can lead to excessive deformation of the foundation pit or even collapse. Furthermore, the actual effectiveness of anchor cables is affected by soil conditions, on-site installation quality, and the installation skills of construction workers. Therefore, to improve the support effect of cantilever support structures, expand the design bearing capacity range of anchor cable structures, and ensure the stability of the foundation pit retaining structure, it is necessary to develop an anchor cable structure that can actively control the deformation of the foundation pit. Utility Model Content

[0003] The purpose of this invention is to address the problems of traditional anchor cable construction, which is complex, leads to long construction periods and high costs; and the limitations of conventional angle bracing, which is only suitable for small and relatively regular excavation surfaces for foundation pit walers, and the inherent instability of steel pipes when used for connection. This invention proposes an active deformation control anchor cable structure for foundation pits. The proposed anchor cable structure forms the retaining structure of the foundation pit waler, resisting lateral deformation of the unexcavated soil. This anchor cable structure is composed of multiple layers of barbs and arrow shafts, offering greater ease of construction compared to traditional anchor cables while achieving the same anchor stress. It also allows for asymmetrical arrangement based on the waler depth. The anchor cable structure includes jacks for active control of lateral deformation of the foundation pit waler. This active deformation control anchor cable structure effectively solves the construction problems of foundation pit waler retaining structures.

[0004] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0005] The active deformation control anchor cable structure includes an arrowhead, an arrow shaft, barb assemblies, and a seal. The arrow shaft is installed in the corresponding anchor cable mounting hole on the side wall of the foundation pit waler through the seal. The two ends of the arrow shaft are respectively located inside and outside the foundation pit waler. The arrowhead is fixedly connected to the end of the arrow shaft located outside the foundation pit waler. Multiple barb assemblies are arranged sequentially and spaced apart along the axial direction of the arrow shaft outside the arrow shaft between the side wall of the foundation pit waler and the arrowhead.

[0006] The active deformation control anchor cable structure also includes a jacking component, which is connected to the inner wall of the pit waler and to one end of the arrow rod located inside the pit waler.

[0007] The barb assembly includes barbs, connectors, stop components, and anchor bolts. Multiple barb mounting holes are spaced circumferentially on the outer circumferential side of the arrow shaft. A corresponding connector is fixedly installed in each barb mounting hole. Each barb has a through hole at its tail, and the tail of each barb is fitted over the middle of the connector. Each barb can rotate around the connector. Anchor bolts are also installed at the connectors on both sides of each barb. A stop component is also installed in the middle of each connector to restrict the rotation of the barb.

[0008] The stop assembly includes a spring and a steel rod, which are connected together. The connector at the barb mounting location has a stop assembly mounting hole, and the tail of the barb also has a steel rod mounting hole, which communicates with the through hole at the tail. When the barb is fully extended, the steel rod mounting hole of the barb aligns with the stop assembly mounting hole at the connector, so that the steel rod in the stop assembly mounting hole enters the steel rod mounting hole of the barb, and the steel rod is simultaneously positioned in both the barb and the connector.

[0009] The seal includes a waterproof rubber sleeve.

[0010] The jacking assembly includes an arc-shaped steel plate and a hollow jack. The arc-shaped steel plate is fixedly connected to the side wall of the pit waler. The hollow jack is installed inside the arc-shaped steel plate, and the actuating end of the hollow jack is connected to one end of the jack rod located inside the pit waler.

[0011] A steel brush is also installed at the arrow shaft near the outer wall of the foundation pit waler.

[0012] A valve is also installed at one end of the arrow shaft, which is located inside the waler of the foundation pit.

[0013] When the barbs of the barb assembly are not deployed, the surface formed between all the barb tips of each barb assembly is smaller than the end face of the arrow near the shaft.

[0014] The barbs include connected columnar tails and outwardly curved tips.

[0015] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0016] (1) The anchor cable structure is inserted at the gap between the steel sections. This location is all cement soil, which does not damage the steel sections as the load-bearing structure and ensures the overall strength of the steel sections.

[0017] (2) Active deformation control. This structure is used in conjunction with a hollow jack device. When the side soil is squeezed inward, the jack will apply an outward force to the SMW method pile to prevent the foundation pit from displacing too much and causing it to collapse. The force applied by the jack can be applied in a "trapezoidal graded loading" manner to avoid the jack applying too much force and causing damage to the waler.

[0018] (3) Convenient and fast construction. The structure only requires the use of static pressure equipment to drive it from the insertion hole, through the pile and into the soil. The soil cut by the barbs is reinforced by grouting through the hollow arrow shaft. The construction is convenient and the construction period is relatively short.

[0019] (4) Flexible placement. One of these structures is placed every three piles at the first waler layer and every two piles at the second waler layer. For strata with poor geological conditions, the placement interval can be appropriately reduced.

[0020] (5) Increased working space. The anchor cable structure replaces the horizontal support, increasing the working space, reducing the use of support materials, reducing carbon emissions, and ensuring construction efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the installation of an active deformation control anchor cable structure in a foundation pit.

[0022] Figure 2 This is a cross-sectional view of the foundation pit.

[0023] Figure 3 The diagram shows the structure of the barb, where (a) is the front view of the barb and (b) is the side view of the barb.

[0024] Figure 4 This is a schematic diagram of the barbs in their undeployed state.

[0025] Figure 5 This is a schematic diagram of the spread-out state of the barbs.

[0026] Figure 6 This is a cross-sectional view showing the barbs in the unfolded state.

[0027] Figure 7 This is a structural schematic diagram of the connector.

[0028] Figure 8This is a partial view of the connection where the barbs have not yet unfolded.

[0029] Figure 9 This is a partial view showing the connection of the barbs.

[0030] Figure 10 This is a partial view of the jack installation.

[0031] In the diagram: 1. Arrow, 2. Barb, 3. Connector, 4. Spring, 5. Steel rod, 6. Anchor bolt, 7. Bolt, 8. Arrow shaft, 9. Steel brush, 10. Grouting reinforcement, 11. Waterproof sleeve, 12. Curved steel plate, 13. Hollow jack, 14. Valve. Detailed Implementation

[0032] To further understand the content of this utility model, a detailed description of the utility model is provided in conjunction with the embodiments. The following embodiments are explanations of the utility model and are not limited to these embodiments. A foundation pit is 540m × 50m in size and 40m in depth, with a total excavation volume of 1.08 million cubic meters. The reinforcement structure is arranged along the waler. After determining the position of the insertion hole, an insertion hole with a diameter of 300mm is opened along a direction perpendicular to the waler.

[0033] like Figure 1 , Figure 2 and Figure 10 As shown, several active deformation control anchor cable structures are arranged on the sidewall of the foundation pit waler. The anchor cable installation holes on the sidewall of the foundation pit waler can be arranged symmetrically or asymmetrically, and can be in an array or opened according to actual needs. Each active deformation control anchor cable structure includes an arrow 1, an arrow shaft 8, a barb assembly, a seal, and a jacking assembly. The arrow shaft 8 is installed in the corresponding anchor cable installation hole on the sidewall of the foundation pit waler through the seal. The two ends of the arrow shaft 8 are respectively set inside and outside the foundation pit waler. The arrow 1 is fixed to the end of the arrow shaft 8 set outside the foundation pit waler, and the arrow 1 points out of the foundation pit waler. The arc-shaped steel plate 12 of the jacking assembly is connected to the inner sidewall of the foundation pit waler. The hollow jack 13 of the jacking assembly is connected to the end of the arrow shaft 8 set inside the foundation pit waler. Multiple barb assemblies are arranged sequentially and spaced apart along the axial direction of the arrow shaft 8 outside the arrow shaft 8 between the sidewall of the foundation pit waler and the arrow 1. In this embodiment, four barb assemblies are installed at eight points on each arrow shaft.

[0034] like Figure 6As shown, the barb assembly includes barbs 2, bolts 7, grouting reinforcement 10, connectors 3, stop components, and anchor bolts 6. The arrow shaft 8 is a hollow structure, with multiple barb mounting holes spaced circumferentially on its outer circumferential side. A corresponding connector 3 is fixedly installed in each barb mounting hole, and the connector 3 is connected to the arrow shaft 8 by bolts 7. Each barb 2 has a through hole at its tail, and the tail of each barb 2 is fitted outside the middle of the connector 3, meaning the connector 3 is located in the through hole at the tail of each barb 2. Each barb 2 can rotate around the connector 3. Corresponding anchor bolts 6 are also installed at the connectors 3 on both sides of each barb 2 to limit lateral displacement during barb rotation. A stop component is also installed in the middle of each connector 3 to limit the rotation of the barb 2. All barbs 2 in each barb assembly are initially in a retracted state, i.e., not extended, as shown below. Figure 4 As shown. The fully extended state of all barbs 2 of each barb assembly is as follows. Figure 5 As shown, each barb 2 is perpendicularly positioned to the arrow shaft 8. At this time, the stop assembly restricts the rotation of the barb 2. When the barb assembly is fully extended (i.e., rotated 90°), grouting is performed from the tail of the arrow shaft 8. The structure formed after the grout solidifies near the barb 2 is denoted as the grouting solidified body 10. After the anchor cable installation holes are opened on the side wall of the foundation pit waler, the arrow 1 of the active deformation control anchor cable structure extends from inside the foundation pit waler through the corresponding anchor cable installation hole to the outside of the foundation pit waler. During the installation process of this active deformation control anchor cable structure, all the barbs 2 of the barb assembly gradually open after encountering the mud and sand outside the foundation pit waler until they are fully open. At this time, the stop assembly at the barb 2 works, causing the barb 2 to stop rotating. In this embodiment, each barb assembly is provided with four barbs arranged at equal intervals along the circumference.

[0035] like Figure 7 , Figure 8 and Figure 9 As shown, the stop assembly includes a spring 4 and a steel rod 5. One end of the spring 4 and one end of the steel rod 5 are fixedly connected, and the spring 4 is in a compressed state. A stop assembly mounting hole is provided in the connector 3 at the installation location of the barb 2, and a steel rod mounting hole is also provided at the tail of the barb 2. The steel rod mounting hole communicates with the through hole at the tail. The barb 2 rotates around the connector 3. When the barb 2 is fully extended, the steel rod mounting hole of the barb 2 is aligned with the stop assembly mounting hole at the connector 3, so that the steel rod 5 in the stop assembly mounting hole enters the steel rod mounting hole of the barb 2. The steel rod 5 is simultaneously set in the barb 2 and the connector 3 to restrict the rotation of the barb 2.

[0036] The sealing element includes a waterproof rubber sleeve 11, which is used to prevent grout from entering the interior of the excavation face of the foundation pit waler.

[0037] The jacking assembly includes an arc-shaped steel plate 12 and a hollow jack 13. The arc-shaped steel plate 12 is fixedly connected to the side wall of the pit waler by a weld. The hollow jack 13 is installed inside the arc-shaped steel plate 12. The actuating end of the hollow jack 13 is connected to one end of the arrow rod 8 located inside the pit waler. The hollow jack 13 is used to restrict the movement of the arrow rod 8 into the pit waler.

[0038] A steel brush 9 is also installed at point 8 on the outer wall of the foundation pit waler to prevent mud and sand from flowing back during the grouting process.

[0039] A valve 14 is also installed at one end of the arrow shaft 8 inside the waler of the foundation pit to control the grouting rate of the cement slurry.

[0040] When the barbs 2 of the barb assembly are not deployed, the surface formed between the tips of all the barbs 2 in each barb assembly is smaller than the end face of arrow 1 near the shaft 8. That is, along the axial direction of the shaft 8, the end face of arrow 1 covers the surface formed between the tips of all the barbs 2 in each barb assembly. Figure 4 As shown, the distance L1 between the tips of two opposite barbs 2 in each barb assembly is less than the side length L2 of the end face of the arrow shaft 8.

[0041] like Figure 3 (a) and Figure 3 As shown in (b), the barb 2 includes a connected columnar tail and an outwardly curved tip.

[0042] The construction process of the active deformation control anchor cable structure for the foundation pit waler is as follows:

[0043] Step 1: After the construction of the waler foundation pit of the station is completed, determine the number of holes according to the number of SMW method piles and number them sequentially. Use a down-the-hole impact drill to perform "skip drilling" on the side wall of the waler foundation pit, with the drilling depth exceeding the length of the active deformation control anchor cable structure set outside the waler; "skip drilling" specifically means that after drilling the first hole, the drill rig drills the third hole, then the fifth hole, then the second hole, then the fourth hole, and so on.

[0044] Step 2: Using a static pressure device, install the arrow 1, arrow shaft 8, barb assembly, and seal of each active deformation control anchor cable structure into the corresponding anchor cable mounting holes. When the barb 2 contacts the soil, it will rotate around the connector 3 by 90°. After the barb rotates 90°, the steel rod 5 aligns with the small hole of the barb 2, and the pressure of the compressed spring 4 is released, causing the steel rod 5 to pop out and pass through the steel rod mounting hole of the barb 2, fixing the barb 2 at the current horizontal height. The barb 2 is in an unfolded state.

[0045] Step 3: Open the valves of each active deformation control anchor cable structure and use a grouting machine to perform grouting. The grout is injected from the tail of the active deformation control anchor cable structure and flows out through the barbed installation hole in the arrow shaft until grouting is complete. When the grout level no longer decreases over a long period of time, it indicates that grouting is complete, and the valves can be closed. Secondary grouting can be performed depending on the grouting situation. Grouting of the anchor cable holes is carried out using a grouting machine, and the grouting pressure is maintained at 0.3-0.6 MPa.

[0046] Step 4: Install the corresponding jacking component at the tail of the arrow shaft 8 of each active deformation control anchor cable structure.

[0047] The present invention has been described in detail above with reference to the embodiments. However, the description 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 in accordance with the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. An actively deformable control anchor structure for a foundation pit, characterized by, The active deformation control anchor cable structure includes an arrow (1), an arrow shaft (8), barb components, and a seal. The arrow shaft (8) is installed in the anchor cable mounting hole corresponding to the side wall of the foundation pit waler through the seal. The two ends of the arrow shaft (8) are respectively set inside the foundation pit waler and outside the foundation pit waler. The arrow (1) is fixedly connected to one end of the arrow shaft (8) set outside the foundation pit waler. Multiple barb components are arranged sequentially and spaced along the axial direction of the arrow shaft (8) outside the arrow shaft (8) between the side wall of the foundation pit waler and the arrow (1).

2. The actively deformable control anchor structure for a foundation pit according to claim 1, characterized in that, The active deformation control anchor cable structure also includes a jacking component, which is connected to the inner wall of the pit waler and is connected to one end of the arrow rod (8) located inside the pit waler.

3. The actively deformable control anchor structure for a foundation pit according to claim 1, characterized in that, The barb assembly includes barbs (2), connectors (3), stop components, and anchor bolts (6); the outer circumferential side of the arrow shaft (8) is provided with multiple barb mounting holes arranged at intervals along the circumference, and a corresponding connector (3) is fixedly installed in each barb mounting hole. Each barb (2) has a through hole at its tail, and the tail of each barb (2) is sleeved outside the middle of the connector (3). Each barb (2) can rotate around the connector (3). A corresponding anchor bolt (6) is also installed at the connector (3) on both sides of each barb (2). A stop component is also installed in the middle of each connector (3) to limit the rotation of the barb (2).

4. The actively deformable control anchor structure for a foundation pit according to claim 3, characterized in that, The stop assembly includes a spring (4) and a steel rod (5), which are connected. The connector (3) at the installation location of the barb (2) has a stop assembly installation hole, and the tail of the barb (2) also has a steel rod installation hole, which is connected to the through hole at the tail. When the barb (2) is fully extended, the steel rod installation hole of the barb (2) is aligned with the stop assembly installation hole at the connector (3), so that the steel rod (5) in the stop assembly installation hole enters the steel rod installation hole of the barb (2), and the steel rod (5) is simultaneously placed in the barb (2) and the connector (3).

5. The actively deformable control anchor structure for a foundation pit according to claim 1, characterized in that, The seal includes a waterproof rubber sleeve (11).

6. The actively deformable control anchor structure for a foundation pit according to claim 2, characterized in that, The jacking assembly includes an arc-shaped steel plate (12) and a hollow jack (13). The arc-shaped steel plate (12) is fixedly connected to the side wall of the pit waler. The hollow jack (13) is installed inside the arc-shaped steel plate (12). The execution end of the hollow jack (13) is connected to one end of the arrow rod (8) located inside the pit waler.

7. The actively deformable control anchor structure for a foundation pit according to claim 3, characterized in that, A steel brush (9) is also installed at the arrow shaft (8) near the outer wall of the foundation pit waler.

8. The actively deformable control anchor structure for a foundation pit according to claim 3, characterized in that, A valve (14) is also installed at one end of the arrow shaft (8) inside the foundation pit waler.

9. The actively deformable control anchor structure for a foundation pit according to claim 3, characterized in that, When the barbs (2) of the barb assembly are not deployed, the surface formed between the tips of all the barbs (2) of each barb assembly is smaller than the end face of the arrow (1) near the shaft (8).

10. The actively deformable control anchor structure for a foundation pit according to claim 3, characterized in that, The barb (2) includes a connected columnar tail and an outwardly curved tip.

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