Foundation pit slope anchoring device and construction method thereof

Abstract

The invention relates to the technical field of civil engineering foundation pit supporting, in particular to a foundation pit slope anchoring device and a construction method thereof.The foundation pit slope anchoring device comprises an anchor rod body, an expander pushing rod, an expander expanding head, grout overflow holes, a multi-stage wedge-shaped anchoring part and an anchor rod bottom external expanding part, and the multiple grout overflow holes are formed in the anchor rod body; the multi-stage wedge-shaped joints provide on-way anchoring, the bottom umbrella-shaped supports provide end anchoring, the overflow grouting achieves integral consolidation, and the three parts have a synergistic effect, so that the anchoring reliability and bearing capacity in complex artificial soil filling are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation pit support in civil engineering, and in particular to a foundation pit slope anchoring device and a construction method thereof. Background Art

[0002] Against the backdrop of accelerating urbanization, deep foundation pit projects face increasingly complex geological challenges, particularly in the widespread Quaternary Holocene artificial fill areas of my country, characterized by loose structure, complex composition, poor uniformity, and weak self-stabilization. Excavation in such strata is highly susceptible to engineering risks such as slope instability and excessive deformation of support structures, placing higher demands on the reliability and adaptability of anchoring technology.

[0003] Traditional anchor support technology mostly uses the bonding effect between equal-section grouting bodies and soil to provide anchoring force, but it exposes the following technical bottlenecks in artificial fill strata: First, the chaotic particle grading and uneven density of the fill lead to disordered diffusion of the grouting liquid, making it difficult to form a continuous and dense anchor body, and the bonding strength of the slurry-soil interface is highly discrete; second, traditional mechanically expanded anchor rods mostly use a single expanded diameter structure, which has insufficient penetration power for complex fill layers containing construction waste and backfill gravel, and cannot achieve multi-level stress transfer. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a foundation pit slope anchoring device and a construction method thereof to solve the above problems.

[0005] A foundation pit slope anchoring device includes an anchor rod body inserted into a soil layer, a multi-stage wedge-shaped anchoring component provided on the anchor rod body, and an upper Ω-shaped fixed anchoring ring and a lower Ω-shaped fixed anchoring ring mounted on the surface of the anchor rod body, serving as support points for the multi-stage wedge-shaped anchoring component.

[0006] It also includes an uploading force connecting rod, a middle force transmitting connecting rod and a lower force transmitting connecting rod, one end of the uploading force connecting rod and the lower force transmitting connecting rod are movably connected to the upper Ω-shaped fixed anchor ring and the lower Ω-shaped fixed anchor ring respectively, and the uploading force connecting rod and the lower force transmitting connecting rod are connected by a middle force transmitting connecting rod movable rod;

[0007] The system also includes a connecting rod extension hole, which is set on the surface of the anchor rod body. When the upper and middle force transmission connecting rods expand, they extend outward through the connecting rod extension hole and embed into the soil layer. This solves the problem of the bottom umbrella-shaped support body being stuck and unable to fully expand in complex fill. The preset outward angle reduces the initial expansion resistance, and the guide rod guides the expansion direction, ensuring that the tripod is reliably formed in the gravel-containing soil layer.

[0008] The bottom end of the anchor rod body is provided with an anchor rod bottom expansion component and a guide rod. The anchor rod bottom expansion component includes an Ω-shaped fixed anchor ring on the upper part of the outward expansion force transmission rod arranged on the surface of the anchor rod body, and also includes an uploading force link on the outward expansion force transmission rod and a lower force transmission link on the outward expansion force transmission rod. One end of the uploading force link on the outward expansion force transmission rod is movably connected to the Ω-shaped fixed anchor ring on the upper part of the outward expansion force transmission rod, and the other end is connected to one end of the lower force transmission link of the outward expansion force transmission rod. The other end of the lower force transmission link of the outward expansion force transmission rod is connected to a tripod.

[0009] A force transmission tripod connecting movable ring is provided on the tripod, and a force transmission connecting rod under the outward-expanding force transmission rod is connected to the tripod through the force transmission tripod connecting movable ring.

[0010] It also includes a support rod, the two ends of which are respectively connected to the middle surface of the support rod and the surface of the anchor rod body, so that the initial outward expansion angle of the anchor rod bottom expansion part is 10° to 15°.

[0011] An expander rod is installed inside the anchor body, with a frustum-shaped expander head connected to its bottom end. The expander head is equal in length to the anchor body, with its top end extending to the entrance of the anchor hole. This solves the problems of low expansion force transmission efficiency and ineffective activation of deep nodes in traditional expanded anchor rods. The conical expander head efficiently converts axial lifting force into radial expansion force, and the equal-length expander rod ensures synchronous expansion of deep anchor nodes, achieving stress transmission throughout the entire hole.

[0012] When the expander enlarged head is lifted, the middle force transmission link and its connecting shaft are pushed, forcing the upper force transmission link and the lower force transmission link to open radially outward around their fixed ring and movable ring to form a wedge-shaped structure.

[0013] Multiple such components are arranged at intervals along the length of the anchor rod to form multi-level, discrete mechanical bite points, which significantly increase the contact area and friction resistance between the anchor rod and the soil, provide strong immediate mechanical anchoring force, effectively penetrate complex fill and disperse stress.

[0014] Pressure applied by the front end of the anchor rod drives the uplink and downlink of the outward expansion dowel rod to expand outward, ultimately expanding the tripod into an umbrella shape. The tripod is made of bent steel bars and forms the core skeleton of the umbrella-shaped support, providing the main load-bearing area.

[0015] This large bottom support provides extremely strong end bearing force at the bottom of the anchor rod and significantly increases the contact with the deep soil, effectively resisting the uplift force.

[0016] A plurality of overflow holes are provided on the anchor rod body at intervals along the axial direction. The distribution positions of the overflow holes correspond to the expansion areas of the multi-stage wedge-shaped anchoring components. The aperture range of the overflow holes is 8 to 12 mm.

[0017] Grout is injected through the overflow holes in the anchor body, permeating, filling, and solidifying the gaps between the mechanical expansion and the surrounding soil. This creates a snap-fit anchor, chemically bonding the mechanical expansion body to the surrounding soil, further enhancing anchoring strength, sealing, and long-term stability. Mechanical expansion creates favorable conditions for grouting, which in turn reinforces and integrates the effects of mechanical expansion.

[0018] This solves the problem of disordered grout diffusion and discontinuous anchoring in loose fill caused by traditional grouting. By controlling the position and diameter of the overflow holes, the grout is ensured to accurately fill the gaps created by mechanical expansion, forming a snap-fit anchoring body and improving the bond strength between the grout and soil.

[0019] The opening length L of the connecting rod extension hole on the anchor rod body satisfies: L=0.8×(upper force transmission connecting rod length+middle force transmission connecting rod length), and the opening width is 1.2 to 1.5 times the connecting rod diameter.

[0020] Solve the problems of interference with the rod body and insufficient extension angle during expansion of the multi-stage connecting rod system. By optimizing the opening size, the force transmission connecting rod can smoothly extend to the designed angle, maximizing the contact area between the wedge node and the soil.

[0021] Multi-stage wedge-shaped anchor components are arranged in groups of three, with node spacing within each group of 0.3 to 0.5 meters. Multiple groups of multi-stage wedge-shaped anchor components are arranged along the length of the anchor rod's outer surface, with adjacent groups spaced 1.2 to 1.8 meters apart. This addresses the issues of uneven anchoring force distribution along depth and stress concentration. The grouped, discretized layout achieves a hierarchical distribution of anchoring force, avoiding localized soil stress overload and adapting to the heterogeneous characteristics of the fill layer.

[0022] A construction method using a foundation pit slope anchoring device comprises the following steps:

[0023] (1) Positioning and drilling preparation: Accurately stake out anchor points at the designed location of the foundation pit slope, calibrate the drilling inclination using a total station, select a percussive rotary drill, penetrate the gravel fill layer, and drill a hole with a diameter of ≥150mm and a depth exceeding the design value by 0.5m, leaving space for expansion of the bottom umbrella-shaped support. Immediately after drilling, use an in-hole camera to inspect and remove loose soil or obstacles on the hole wall to ensure that the hole is unobstructed;

[0024] (2) Anchor bolt segment installation: The prefabricated anchor bolt is hoisted into the hole segment by segment. The bottom segment: The anchor bolt body with welded support rods and guide rods is installed toward the bottom of the hole. The support rods are preset at a 12° outward angle to reduce the initial expansion resistance.

[0025] Middle and upper segments: Connect each segment with high-strength sleeves, and control the straightness deviation within ±2°. Check whether the connecting rod extension hole of the multi-level wedge node system is aligned with the direction of the weak layer of the soil;

[0026] (3) Activate the bottom umbrella-shaped support: Apply axial pressure to the front end of the anchor rod at the hole mouth to push the outward-expanding force transmission rod component to move. The uplink force transmission rod on the outward-expanding force transmission rod is pressed downward, and the downlink force transmission rod is driven by the connecting shaft. The tripod is expanded along the direction of the guide rod to form an umbrella-shaped support body with a diameter of ≥300mm. The support body is embedded in the deep dense soil layer to provide end-bearing anchoring force.

[0027] (4) Lifting the middle multi-stage anchor node: Insert the expander push rod into the center channel of the anchor rod, and hydraulically lift the expander head with a cone angle of 30°:

[0028] First stage expansion: expand the overhead lifting center force transmission connecting rod, and the blocking rod locks the connecting shaft;

[0029] Second stage expansion: The middle force transmission link pushes the upper force transmission link and the lower force transmission link to expand radially from the outer hole, forming a structure in which each group of three nodes is distributed at 120 degrees, and the wedge-shaped anchor claws penetrate the soil;

[0030] (5) High-pressure grouting consolidation: Grouting is performed within 1 hour after the expansion is completed. Cement slurry is injected through the central grouting pipe at a constant pressure of 0.6 MPa. The slurry seeps out from the overflow hole in a directional manner to fill the cavity formed by the expansion of the node.

[0031] (6) Cyclic construction and acceptance: The spacing between adjacent anchor rods is ≤1.5m, and the construction is carried out according to the same process. The pull-out resistance of the first batch of anchor rods is verified. In sections containing construction waste, the spacing between multi-level node groups is increased to 1.0m to enhance local deformation resistance.

[0032] Compared to existing technologies, this invention offers the following advantages: It utilizes a multi-stage mechanical expansion system, with node components and bottom components actively embedded in loose soil, providing strong and immediate mechanical anchoring force, effectively overcoming the drawbacks of low fill cohesion and insufficient penetration of a single expansion diameter. Grouting is then performed through overflow holes to achieve chemical consolidation, integrating the mechanical expansion element with the soil, further enhancing anchoring effectiveness and long-term stability.

[0033] Multi-level wedge-shaped nodes provide along-the-way anchoring, bottom umbrella-shaped supports provide end anchoring, and overflow grouting achieves overall consolidation. The synergistic effect of the three significantly improves the anchoring reliability and bearing capacity in complex artificial fills. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] Figure 1 This is a cross-sectional view of a soil foundation pit slope anchoring device;

[0036] Figure 2 It is a horizontal cross-sectional view of a multi-stage wedge-shaped anchor node component;

[0037] Figure 3 This is a side view of the dowel rod connection structure of the multi-level wedge-shaped anchor node component;

[0038] Figure 4 It is a horizontal cross-sectional view of the dowel rod component with the bottom of the rod expanded outward;

[0039] Figure 5 This is a top view of the tripod's force transmission components;

[0040] Figure 6 This is a side view of the structure of the expansion component at the bottom of the anchor rod;

[0041] Figure 7 for Figure 1 Enlarged view of part A;

[0042] Figure 8 for Figure 1 Enlarged view of part B.

[0043] In the picture:

[0044] 1. Anchor body;

[0045] 2. Expander push rod;

[0046] 3. Expander expansion head;

[0047] 4. Overflow hole;

[0048] 5. Multi-stage wedge-shaped anchoring components;

[0049] 501, upper Ω-shaped fixed anchor ring;

[0050] 502, upper movable ring of the force-transmitting connecting rod;

[0051] 504, uploading force connecting rod;

[0052] 505, the first force transmission connecting rod is connected to the movable ring;

[0053] 506, first force transmission connecting rod connecting shaft;

[0054] 507, center force transmission connecting rod;

[0055] 5071, guardrail weld;

[0056] 5072, lever;

[0057] 508, the second force transmission connecting rod is connected to the movable ring;

[0058] 509, second force transmission connecting rod connecting shaft;

[0059] 510, lower force transmission connecting rod;

[0060] 511, lower Ω-shaped fixed anchor ring;

[0061] 512, lower force transmission connecting rod movable ring;

[0062] 513, connecting rod extension hole;

[0063] 6. Anchor bolt bottom expansion component;

[0064] 601, Ω-shaped fixed anchor ring on the upper part of the outward-expanding force transmission rod;

[0065] 602, movable ring on the force transmission connecting rod on the outward-expanding force transmission rod;

[0066] 604, force transmission connecting rod on the outward-expanding force transmission rod;

[0067] 6072, bottom outward expansion force transmission rod stop bar;

[0068] 605, the first force transmission connecting rod of the outward expansion force transmission rod is connected to the movable ring;

[0069] 606, the first force transmission connecting rod connecting shaft of the outward expansion force transmission rod;

[0070] 607, outward expansion force transmission rod lower force transmission connecting rod;

[0071] 609, force transmission tripod connected to the movable ring;

[0072] 610, tripod;

[0073] 611, guide rod;

[0074] 612, support rod; DETAILED DESCRIPTION

[0075] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0076] The application principle of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0077] Example 1

[0078] like Figure 1 As shown, a foundation pit slope anchoring device includes an anchor body 1 inserted into a soil layer, and a multi-stage wedge-shaped anchoring component 5 is provided on the anchor body 1. The multi-stage wedge-shaped anchoring component 5 includes an upper Ω-shaped fixed anchor ring 501 and a lower Ω-shaped fixed anchor ring 511 installed on the surface of the anchor body 1, which serve as support points for the multi-stage wedge-shaped anchoring component 5;

[0079] It also includes an upper force transmission link 504, a middle force transmission link 507 and a lower force transmission link 510, and one end of the upper force transmission link 504 and the lower force transmission link 510 are movably connected to the upper Ω-shaped fixed anchor ring 501 and the lower Ω-shaped fixed anchor ring 511 respectively, and the upper force transmission link 504 and the lower force transmission link 510 are movably connected through the middle force transmission link 507; both ends of the middle force transmission link 507 are connected to a blocking rod 5072 to prevent the middle force transmission link 507 from falling out.

[0080] It also includes a connecting rod extension hole 513, which is set on the surface of the anchor rod body 1. When the upper force transmission connecting rod 504 and the middle force transmission connecting rod 507 expand, they extend outward through the connecting rod extension hole 513 and embed into the soil layer.

[0081] Example 2

[0082] like Figure 1-8 As shown, an anchoring device for foundation pit excavation slope includes an anchor rod body 1, an expander propulsion rod 2, an expander enlarged head 3, a grouting hole 4, a multi-stage wedge-shaped anchoring component 5, and an anchor rod bottom expansion component 6.

[0083] A plurality of overflow holes 4 are provided on the anchor rod body 1 , an anchor rod bottom expansion component 6 is provided at the bottom of the anchor rod body 1 , and a plurality of multi-stage wedge-shaped anchoring components 5 are provided at a certain interval in the middle of the anchor rod body 1 .

[0084] The expander propulsion rod 2 is welded to the expander enlarged head 3 , and the length of the expander propulsion rod 2 must match the length of the anchor rod body 1 .

[0085] The multi-stage wedge-shaped anchoring component 5 includes an upper Ω-shaped fixed anchoring ring 501, an upper movable ring 502 of the upper force transmission link, an upper Ω-shaped fixed anchoring ring weld 503, a force transmission link 504, an upper and middle force transmission link connecting movable ring 505, a first force transmission link connecting shaft 506, a middle force transmission link 507, a second force transmission link connecting movable ring 508, a middle and second force transmission link connecting shaft 509, a lower force transmission link 510, a lower Ω-shaped fixed anchoring ring 511, a lower force transmission link movable ring 512, and a connecting rod extension hole 513. The middle force transmission link 507 includes a stop rod weld 5071 and a stop rod 5072.

[0086] The upper movable ring 502 of the force transmission link is inserted into the upper Ω-shaped fixed anchor ring 501 in advance, and the upper Ω-shaped fixed anchor ring 501 is connected to the anchor rod body 1 through the upper Ω-shaped fixed anchor ring weld 503. The force transmission link 504 is welded to the upper movable ring 502 of the force transmission link and the first force transmission link connecting movable ring 505.

[0087] The lower force transmission link 510 is welded to the second force transmission link connecting movable ring 508 and the lower force transmission link movable ring 512. The lower force transmission link movable ring 512 is inserted into the lower Ω-shaped fixed anchor ring 511 in advance, and the lower Ω-shaped fixed anchor ring 511 is welded to the anchor rod body 1.

[0088] The middle force transmission link 507 is integrated with the first force transmission link connecting shaft 506 and the second force transmission link connecting shaft 509. The connecting shaft is bent out by mechanical cold bending, and the end of the connecting shaft is connected to the stop rod 5072 by a stop rod weld 5071. The middle force transmission link 507 is extended into the first force transmission link connecting movable ring 505 and the second force transmission link connecting movable ring 508 in advance, and is then welded together by the stop rod 5072 through the stop rod weld 5071 to form a whole.

[0089] The lower force transmission link movable ring 512 is inserted into the lower Ω-shaped fixed anchor ring 511 in advance, and the lower Ω-shaped fixed anchor ring 511 is connected to the anchor rod body 1 through the lower Ω-shaped fixed anchor ring weld 503 .

[0090] A connecting rod extending hole 513 is opened on the anchor rod body 1 , and the length and width of the opening correspond to 0.8 times the sum of the lengths of the force transmitting connecting rod 504 and the middle force transmitting connecting rod 507 .

[0091] The multi-stage wedge-shaped anchoring components 5 are grouped into three, and a group of multi-stage wedge-shaped anchoring components 5 is arranged at a certain interval in the length direction of the anchor rod body 1.

[0092] The outward expansion component 6 at the bottom of the anchor rod includes an Ω-shaped fixed anchor ring 601 on the upper part of the outward expansion force transmission rod, a movable ring 602 on the force transmission link on the outward expansion force transmission rod, an Ω-shaped fixed anchor ring weld 603 on the upper part of the outward expansion force transmission rod, a force transmission link 604 on the outward expansion force transmission rod, a movable ring 605 connecting the upper and lower force transmission links of the outward expansion force transmission rod, an upper and second force transmission link connecting shaft 606 of the outward expansion force transmission rod, a weld 6071 of the bottom outward expansion force transmission rod stop rod, a bottom outward expansion force transmission rod stop rod 6072, a lower force transmission link 607 of the outward expansion force transmission rod, a movable ring 609 connecting the lower force transmission link and the force transmission tripod, a movable ring connecting the force transmission tripod, a tripod 610, a guide rod 611, and a support rod 612.

[0093] The movable ring 602 on the force transmission link of the outward-expanding force transmission rod is inserted into the Ω-shaped fixed anchor ring 601 on the upper part of the outward-expanding force transmission rod in advance, and the Ω-shaped fixed anchor ring 601 on the upper part of the outward-expanding force transmission rod is connected to the anchor rod body 1 through the Ω-shaped fixed anchor ring weld 603 on the upper part of the outward-expanding force transmission rod. The force transmission link 604 on the outward-expanding force transmission rod is welded to the movable ring 602 on the force transmission link of the outward-expanding force transmission rod, and the bottom of the force transmission link 604 on the outward-expanding force transmission rod is mechanically bent to form the upper and second force transmission link connecting shafts 606 of the outward-expanding force transmission rod.

[0094] The lower force transmission link 607 of the outward-expanding force transmission rod is welded to the movable ring 605 connecting the upper and lower force transmission links of the outward-expanding force transmission rod and the movable ring 609 connecting the lower force transmission link and the force transmission tripod.

[0095] The force transmission link 604 on the outward expansion force transmission rod passes through the upper and second force transmission link connecting shafts 606 of the outward expansion force transmission rod and enters the upper and lower force transmission link connecting movable ring 605 of the outward expansion force transmission rod, and the bottom outward expansion force transmission rod stop rod 6072 is welded to the upper and second force transmission link connecting shafts 606 of the outward expansion force transmission rod through the bottom outward expansion force transmission rod stop rod weld 6071 to form a whole.

[0096] The tripod 610 is made of steel bars and bent into shape. The three corners of the tripod 610 are processed into the shape of a force transmission tripod connecting movable ring 609. The tripod 610 is provided with an opening, and the lower force transmission connecting rod and the force transmission tripod connecting movable ring 609 are inserted into the tripod 610 and then welded closed.

[0097] A guide rod 611 is provided at the bottom of the anchor rod body 1 and is welded to the anchor rod body 1. A support rod 612 is provided on the side of the bottom of the anchor rod body 1. The length of the support rod 612 ensures that the outward expansion component 6 at the bottom of the anchor rod has a certain outward angle, which is convenient for subsequent expansion.

[0098] Example 3

[0099] A construction method using a foundation pit slope anchoring device comprises the following steps:

[0100] 1. Positioning and Drilling Preparation: Accurately stake out anchor points at the designed location on the foundation pit slope, calibrate the drilling inclination using a total station, select a percussive rotary drill, and drill through the gravel-containing fill layer. The drill hole diameter must be ≥150mm and the depth must exceed the designed value by 0.5m, leaving space for the bottom umbrella-shaped support to expand. Immediately after drilling, inspect the hole with an in-hole camera and remove any loose soil or obstacles on the hole wall to ensure the hole is unobstructed.

[0101] 2. Anchor bolt segment installation: The prefabricated anchor bolt is hoisted into the hole segment by segment. The bottom segment: The anchor bolt body 1 with the welded support rod 612 and the guide rod 611 is installed toward the bottom of the hole. The support rod is preset at a 12° outward angle to reduce the initial expansion resistance.

[0102] Middle and upper segments: Connect each segment with a high-strength sleeve, controlling the straightness deviation within ±2°. Check whether the connecting rod extension hole 513 of the multi-level wedge node system 5 is aligned with the direction of the weak layer of the soil;

[0103] 3. Activate the bottom umbrella-shaped support: Apply axial pressure to the front end of the anchor rod at the hole mouth, pushing the outward-expanding force transmission rod component 6 to move. The upward force connection rod 604 on the outward-expanding force transmission rod moves downward under pressure, driving the downward force transmission rod 607 through the connecting shaft 606. The tripod 610 expands along the direction of the guide rod 611 to form an umbrella-shaped support body with a diameter of ≥300mm. The support body is embedded in the deep dense soil layer to provide end-bearing anchoring force.

[0104] 4. Lift the middle multi-stage anchor node: Insert the expander push rod 2 into the center channel of the anchor rod, and hydraulically lift the expander head 3 with a cone angle of 30°:

[0105] First stage expansion: expand the overhead lifting force transmission connecting rod 507, and the blocking rod 5072 locks the connecting shaft;

[0106] Second stage expansion: The middle force transmission link 507 pushes the upper force transmission link 504 and the lower force transmission link 510 to radially expand from the outward extension hole 513, forming a structure in which each group of three nodes is distributed at 120 degrees, and the wedge-shaped anchor claws penetrate the soil;

[0107] 5. High-pressure grouting consolidation: Grouting is carried out within 1 hour after the expansion is completed. Cement slurry is injected through the central grouting pipe at a constant pressure of 0.6 MPa. The slurry seeps out from the overflow hole 4 in a directional manner to fill the cavity formed by the expansion of the node;

[0108] 6. Cyclic construction and acceptance: The spacing between adjacent anchor rods is ≤1.5m. Construction shall be carried out according to the same process. The pull-out resistance of the first batch of anchor rods shall be verified. In sections containing construction waste, the spacing between multi-level node groups 5 shall be increased to 1.0m to enhance local deformation resistance.

[0109] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0110] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A foundation pit slope anchoring device, characterized by: The invention comprises an anchor rod body (1) inserted into a soil layer, wherein a multi-stage wedge-shaped anchoring component (5) is provided on the anchor rod body (1), and the multi-stage wedge-shaped anchoring component (5) comprises an upper Ω-shaped fixed anchoring ring (501) and a lower Ω-shaped fixed anchoring ring (511) mounted on the surface of the anchor rod body (1), serving as support points of the multi-stage wedge-shaped anchoring component (5); The device further comprises an upper force transmission link (504), a middle force transmission link (507) and a lower force transmission link (510), wherein one end of the upper force transmission link (504) and the lower force transmission link (510) are movably connected to the upper Ω-shaped fixed anchor ring (501) and the lower Ω-shaped fixed anchor ring (511), respectively, and the upper force transmission link (504) and the lower force transmission link (510) are movably connected via the middle force transmission link (507). It also includes a connecting rod extension hole (513), which is arranged on the surface of the anchor rod body (1). When the upper force transmission connecting rod (504) and the middle force transmission connecting rod (507) expand, they extend outward through the connecting rod extension hole (513).

2. A foundation pit slope anchoring device according to claim 1, characterized in that: The bottom end of the anchor rod body (1) is provided with an anchor rod bottom outward expansion component (6) and a guide rod (611), the anchor rod bottom outward expansion component (6) includes an Ω-shaped fixed anchor ring (601) on the upper part of the outward expansion force transmission rod provided on the surface of the anchor rod body (1), and also includes a force transmission link (604) on the outward expansion force transmission rod and a force transmission link (607) on the lower part of the outward expansion force transmission rod, one end of the force transmission link (604) on the outward expansion force transmission rod is movably connected to the Ω-shaped fixed anchor ring (601) on the upper part of the outward expansion force transmission rod, and the other end is connected to one end of the force transmission link (607) on the lower part of the outward expansion force transmission rod, and the other end of the force transmission link (607) on the outward expansion force transmission rod is connected to a tripod (610).

3. The foundation pit slope anchoring device according to claim 2, characterized in that: The tripod (610) is provided with a force transmission tripod connecting movable ring (609), and the force transmission connecting rod (607) below the outward-expanding force transmission rod is connected to the tripod (610) via the force transmission tripod connecting movable ring (609).

4. The foundation pit slope anchoring device according to claim 2, characterized in that: It also includes a support rod (612), the two ends of which are respectively connected to the middle surface of the support rod (612) and the surface of the anchor rod body (1), so that the initial outward expansion angle of the anchor rod bottom expansion component (6) is 10° to 15°.

5. The foundation pit slope anchoring device according to claim 1, characterized in that: An expander propulsion rod (2) is provided inside the anchor rod body (1), and the bottom end of the expander propulsion rod (2) is connected to an expander enlargement head (3), and the expander enlargement head (3) is in a frustum shape. The length of the expander propulsion rod (2) is equal to the length of the anchor rod body (1), and the top end thereof extends to the entrance of the anchor hole.

6. The foundation pit slope anchoring device according to claim 4, characterized in that: A plurality of overflow holes (4) are provided on the anchor rod body (1) at intervals along the axial direction. The distribution positions of the overflow holes (4) correspond to the expansion areas of the multi-stage wedge-shaped anchoring components (5). The diameter of the overflow holes (4) ranges from 8 to 12 mm.

7. The foundation pit slope anchoring device according to claim 1, characterized in that: The opening length L of the connecting rod extension hole (513) on the anchor rod body (1) satisfies: L=0.8×(upper force transmission connecting rod length+middle force transmission connecting rod length), and the opening width is 1.2 to 1.5 times the connecting rod diameter.

8. The foundation pit slope anchoring device according to claim 1, characterized in that: The multi-stage wedge-shaped anchoring components (5) are grouped into three, with a node spacing of 0.3 to 0.5 m within the group. The multi-stage wedge-shaped anchoring components (5) are arranged in multiple groups along the length direction of the outer surface of the anchor rod body (1), with a spacing of 1.2 to 1.8 m between adjacent groups.

9. A construction method using a foundation pit slope anchoring device, comprising the foundation pit slope anchoring device according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Positioning and drilling preparation: Accurately stake out anchor points at the designed location of the foundation pit slope, calibrate the drilling inclination using a total station, select a percussive rotary drill, penetrate the gravel fill layer, and drill a hole with a diameter of ≥150mm and a depth exceeding the design value by 0.5m, leaving space for expansion of the bottom umbrella-shaped support. Immediately after drilling, use an in-hole camera to inspect and remove loose soil or obstacles on the hole wall to ensure that the hole is unobstructed; (2) Anchor bolt segment installation: The prefabricated anchor bolt is hoisted into the hole segment by segment. The bottom segment: The anchor bolt body (1) with the welded support rod (612) and the guide rod (611) is installed toward the bottom of the hole. The support rod is preset at a 12° outward angle to reduce the initial expansion resistance. Middle and upper segments: Connect segment by segment through high-strength sleeves, control the straightness deviation within ±2°, and check whether the connecting rod extension hole (513) of the multi-level wedge node system (5) is aligned with the direction of the weak layer of the soil; (3) Activate the bottom umbrella-shaped support: apply axial pressure to the front end of the anchor rod at the hole mouth, push the outward force transmission rod component (6) to move, and the force transmission link (604) on the outward force transmission rod is pressed downward, driving the lower force transmission link (607) through the connecting shaft (606); the tripod (610) is expanded along the direction of the guide rod (611) to form an umbrella-shaped support body with a diameter of ≥300mm; the support body is embedded in the deep dense soil layer to provide end-bearing anchoring force; (4) Lifting the middle multi-stage anchor node: Insert the expander push rod (2) into the center channel of the anchor rod, and hydraulically lift the expander head (3) with a cone angle of 30°: First stage expansion: expanding the overhead lifting force transmission connecting rod (507), and the blocking rod (5072) locks the connecting shaft; Second stage expansion: the middle force transmission link (507) pushes the upper force transmission link (504) and the lower force transmission link (510) to radially expand from the outward extension hole (513); forming a structure in which each group of three nodes is distributed at 120 degrees, and the wedge-shaped anchor claws penetrate the soil; (5) High-pressure grouting consolidation: Grouting is performed within 1 hour after the expansion is completed. Cement slurry is injected through the central grouting pipe at a constant pressure of 0.6 MPa. The slurry seeps out from the overflow hole (4) in a directional manner to fill the cavity formed by the expansion of the node; (6) Cyclic construction and acceptance: The distance between adjacent anchor rods is ≤1.5m, and the construction is carried out according to the same process. The pull-out resistance of the first batch of anchor rods is verified. In the section containing construction waste, the distance between the multi-level node group (5) is increased to 1.0m to enhance the local anti-deformation ability.

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