Shearing-resistant composite anchor cable with locally-enhanced sliding surface and design and construction method of shearing-resistant composite anchor cable

Abstract

The invention relates to the technical field of geotechnical engineering slope reinforcement, in particular to a shear-resistant composite anchor cable with a locally-reinforced sliding face and a design and construction method thereof, and the shear-resistant composite anchor cable is mainly structurally characterized in that a composite shear-resistant section comprises a steel floral tube, a cement mortar grouting body filled in the steel floral tube and an anchor cable penetrating through the steel floral tube; the independent anchoring section is positioned below the composite shear-resistant section and is formed by bonding an anchor cable and a surrounding cement concrete grouting body; the connecting steel pipe is detachably connected to the upper end of the steel floral pipe through a connecting component. The defects that an existing loose soil body slope anchoring structure is insufficient in shear resistance and stress concentration is prone to happening to the end can be overcome, the shear resistance is remarkably improved through a local composite reinforcing means, shear resistance-tensile double reinforcement is achieved through cooperative work of the composite shear resistance section and the independent anchoring section, and by recycling the connecting steel pipe, the shear resistance and tensile strength of the slope anchoring structure are improved. Compared with a traditional permanent sleeve scheme, the steel consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of slope reinforcement technology in geotechnical engineering, and in particular to a shear-resistant composite anchor cable with localized reinforcement of the sliding surface, and its design and construction method. Background Technology

[0002] In rock and soil slope anchoring engineering, traditional prestressed anchor cables rely on the bond between the grout and the soil to transfer tensile force. However, this method has serious mechanical defects in areas with potential sliding soil layers. The sliding zone, as a concentrated area of ​​shear deformation, can experience shear stresses on the anchor cable that are 3-5 times higher than in non-sliding soil layers. Meanwhile, the shear strength of cement-based grout is typically less than 5 MPa, making it highly susceptible to brittle shear failure. This problem is particularly prominent in loose soil slopes: low cohesion (c < 20 kPa) and high rheological properties result in a grout-soil interface bond strength less than 30% of that of the rock mass, leading to nearly 70% of anchoring failures manifesting as grout cracking or interface slippage in the sliding soil layer area.

[0003] Existing reinforcement measures have significant limitations: increasing the diameter or density of anchor cables improves overall tensile strength but exacerbates local stress concentration and increases project costs by more than 40%; while using steel sleeves for local protection delays shear failure, it sacrifices more than 80% of the grout-soil bond area, hindering effective prestress transfer. The fundamental contradiction lies in the mutual exclusivity of tensile and shear properties—strengthening tensile strength amplifies peak shear stress, while rigid shear members weaken the system's coordinated deformation capacity. Especially under rainfall or seismic loads, the repeated shear dilatation effect of loose soil accelerates fatigue damage to the grouting body, resulting in a failure rate of 15-25% for traditional anchor cables.

[0004] Current technology has not yet solved the dual requirements of distributed dissipated shear stress in the sliding soil layer and maintaining the overall bond integrity. There is an urgent need to develop a new type of composite anchor cable structure. By implanting shear-resistant units coupled with the cable body in the sliding zone, shear stress redistribution and multi-level energy dissipation can be achieved, and the shear stiffness and ductility of the system can be improved simultaneously, thus fundamentally breaking through the long-term technical bottleneck in the field of rock and soil anchoring. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of insufficient shear resistance and easy stress concentration at the ends of anchorage structures for loose soil slopes, and to provide a shear-resistant composite anchor cable and its design and construction method that significantly improves shear resistance through local composite reinforcement.

[0006] The technical solution adopted in this invention is a shear-resistant composite anchor cable with locally reinforced sliding surface, comprising a composite shear-resistant section, an independent anchoring section, and a connecting steel pipe, wherein:

[0007] The composite shear-resistant section is located in the potential landslide soil layer area of ​​the slope, including a steel pipe, a cement mortar grouting body filled in the steel pipe, and an anchor cable running through it. The steel pipe covers the vertical thickness area of ​​the landslide soil layer and extends a certain length to both the inside and outside of the landslide soil layer to ensure that the landslide soil layer is completely covered and the stress is fully diffused, the shear force is effectively transferred and stress concentration at the ends is avoided. The cement mortar grouting body is fully filled in the steel pipe, so that the anchor cable is bonded to the inner wall of the steel pipe through the cement mortar grouting body to form a rigid composite body in this section, and the anchor cable is completely wrapped and embedded.

[0008] The independent anchorage section is located below the composite shear section and extends into the stable soil or rock layer. It is formed by the bonding of the anchor cable with the surrounding cement concrete grouting body to form a conventional anchor body, which mainly provides tensile strength. The anchor cable may include a sleeve for protection in this section.

[0009] The connecting steel pipe extends to the slope surface and is detachably connected to the upper end of the steel perforated pipe via a connecting component. It is inserted simultaneously when drilling holes in the soil, which can prevent the loose soil from collapsing. After the grouting inside the steel perforated pipe is filled, it is detached from the connecting steel pipe.

[0010] Furthermore, multiple grouting holes are formed on the wall of the steel pipe. In specific implementations, the opening ratio of the grouting holes is generally set at 15% to 20% to ensure radial penetration of the grout and enhance interfacial bonding. The function of the grouting holes is that when grout is injected into the steel pipe, the grout will flow out from the grouting holes, forming a root pile effect, which further strengthens the shear resistance.

[0011] Furthermore, the cement mortar grouting body uses M30 grade or higher micro-expansion cement mortar, and adds polypropylene fiber with a fiber content of 0.8~1.2kg / m³ to ensure full cross-section filling inside the steel pipe.

[0012] Furthermore, the connecting component includes a first connecting piece fixedly installed inside the upper end of the steel pipe and a second connecting piece fixedly installed on the outer wall of the lower end of the connecting steel pipe. The first connecting piece includes multiple spaced first connecting pieces, and the second connecting piece includes multiple spaced second connecting pieces that correspond to the first connecting pieces and are adapted in shape. The connecting steel pipe and the steel pipe can be misaligned and disengaged by rotating them at a certain angle.

[0013] The present invention also provides a design method for a shear-resistant composite anchor with localized reinforcement of the sliding surface, which is applied to the shear-resistant composite anchor as described above;

[0014] The mechanical design method is based on the following core mechanical assumptions:

[0015] 1. Soil constitutive model: Soil obeys the Mohr-Coulomb criterion. The sliding soil layer is a continuous curved surface;

[0016] 2. Interface behavior: The steel pipe-grouting body interface is completely bonded (without slippage), and the bond stress between the anchor cable and the grouting body is evenly distributed;

[0017] 3. Load transfer: The shear force of the sliding soil layer is borne by the composite shear-resistant segment, while the independent anchorage segment only transfers axial tensile force;

[0018] 4. Simplified calculation: The shear strength of the steel perforated pipe is calculated as a thin-walled circular cross-section (ignoring the weakening effect of the opening), and the bond strength of the grout-soil interface is calculated. Take a constant value.

[0019] Includes the following steps:

[0020] S1. Basic Data Preparation and Stability Analysis:

[0021] Calculate the sliding force:

[0022] In the formula, The sliding force per unit width of the slope (kN / m). The shear strength of the soil (kPa). This represents the actual shear stress (kPa) of the current sliding soil layer. is the length of a micro-segment of the sliding soil layer (m);

[0023] Calculate the total anti-skid force required:

[0024] In the formula, The required total anti-skid force (kN / m). For safety factors, a value of 1.25 to 1.50 (dimensionless) is typically used.

[0025] S2. Stress design of steel perforated pipe:

[0026] S2.1 Determine the length:

[0027]

[0028] In the formula, The design length (m) of the steel perforated pipe. The vertical thickness (m) of the potential sliding soil layer. It is the sum of the lengths (m) of the steel pipe extending to both the inner and outer sides of the sliding soil layer;

[0029] S2.2 Calculate the sliding force in a single hole:

[0030]

[0031] In the formula, Design shear force (kN) for steel pipe. The horizontal spacing (m) between the steel pipes;

[0032] S2.3 Calculate the lateral force:

[0033]

[0034] In the formula, The lateral force (kN) acting on the steel pipe, α is the inclination angle of the sliding surface at the intersection of the anchor cable and the sliding surface (°), and β is the angle between the anchor cable and the horizontal plane (°), which should be downward inclined, generally between 10° and 30°;

[0035] S2.4, Condition 1, the steel pipe is subjected to lateral shear force (assuming the steel pipe is mainly subjected to shear):

[0036] Assume lateral force

[0037] Shear capacity verification:

[0038] In the formula, To design the shear force (N). The yield strength (MPa) of the steel pipe. The outer diameter of the steel flower pipe is (mm). The wall thickness of the steel pipe is (mm). The design value of shear strength of steel pipe is based on the Von Mises criterion (MPa).

[0039] S2.5, Working Condition 2, the cantilevered steel pipe is subjected to lateral force (assuming one end of the steel pipe is fixed):

[0040] Design bending moment

[0041] In the formula, M is the design bending moment (N·mm), and L is the distance (mm) from the point of application of the lateral force to the anchorage end, which should be determined according to the actual geological conditions.

[0042] Bending capacity verification:

[0043] In actual design, the failure of cantilever steel pipes is controlled by the weaker of the bending and shear conditions. Usually, bending failure occurs before shear failure. However, for short and thick cantilever beams, the shear strength should be checked.

[0044] S3, Anchor cable tensile design

[0045] S3.1 Axial tension of the anchor cable by downward force The calculation yields the following formula:

[0046]

[0047] In the formula: The axial tension of the anchor cable (N); The sliding force (N) within the range of a single anchor cable can be determined through landslide stability analysis. The reduction factor should be applied to soil slopes and loose, fractured rock slopes. The angle (°) of the sliding surface at the intersection of the anchor cable and the sliding surface; The angle (°) between the anchor cable and the horizontal plane should preferably be downward, generally between 10° and 30°; The internal friction angle of the sliding surface (°);

[0048] S3.2 The strength of the anchor cable must meet the following conditions:

[0049]

[0050] In the formula: This represents the net cross-sectional area (mm²) of the anchor cable strand. The tensile yield strength (MPa) of the anchor cable steel.

[0051] The present invention also provides a construction method for a shear-resistant composite anchor cable with locally reinforced sliding surface, applicable to the shear-resistant composite anchor cable as described above, comprising the following steps:

[0052] Step S1: Drill holes in loose soil and simultaneously insert the combination of steel pipe and connecting steel pipe into the borehole;

[0053] Step S2: Remove residual soil from inside the steel pipe;

[0054] Step S3: Cable positioning, fix the anchor cable in the center of the steel pipe axis;

[0055] Step S4: Grouting into the borehole. First, inject cement concrete grout to fill the hole of the independent anchoring section, and then inject cement mortar grout to fill the inside of the steel pipe. The grouting pressure of the steel pipe section is ≥0.5MPa and held for 3 minutes.

[0056] Step S5: After the cement mortar grouting inside the steel pipe is filled, rotate the connecting steel pipe to detach it from the steel pipe and pull out the connecting steel pipe.

[0057] Step S6: Install anchors and pressure-bearing plates at the borehole opening;

[0058] Step S7: After the grout in the borehole reaches the design strength, tension the anchor cable and lock it in place using anchors and pads. The anchor cable tensioning is carried out in three stages according to the design tension of 40%, 80%, and 110%.

[0059] The beneficial effects of this invention are as follows:

[0060] 1. Significantly enhanced shear resistance: By setting steel pipes to constrain the grouting body in key areas of the sliding soil layer, a locally reinforced composite shear-resistant body is formed, which effectively resists soil shear deformation; and due to the presence of grouting holes, when grout is injected into the steel pipes, the grout will flow out from the grouting holes, forming a root pile effect, which further enhances the shear resistance.

[0061] 2. Clear functional zoning: The composite shear-resistant section (shear-dominant) and the independent anchorage section (tensile-dominant) work together to achieve a dual reinforcement mechanism of "shear-tensile".

[0062] 3. Economic optimization: The steel pipe recycling rate is 100%, saving 38% of steel consumption compared with the traditional permanent casing solution (based on an average hole depth of 15m).

[0063] 4. Universality of design method: A mechanical design method for shear anchor cable composite structures based on local reinforcement of sliding soil layers is proposed. Through a seven-step closed-loop design process, the mechanical model is coupled with stability verification to ensure the safety and reliability of the structure.

[0064] 5. Good construction adaptability: The steel pipe can be installed and grouted simultaneously with the anchor cable, without the need for additional complicated processes, and is suitable for the rapid reinforcement of loose soil slopes. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the structure of the shear-resistant composite anchor cable embedded in the slope according to an embodiment of the present invention (after the connecting steel pipe is pulled out).

[0066] Figure 2 This is a schematic diagram of the stress analysis of a shear-resistant composite anchor cable embedded in a slope according to an embodiment of the present invention;

[0067] Figure 3 This is a schematic diagram of the overall structure of the shear-resistant composite anchor cable according to an embodiment of the present invention;

[0068] Figure 4 This is a schematic diagram of the steel perforated pipe structure according to an embodiment of the present invention;

[0069] Figure 5 This is a schematic diagram of the connecting steel pipe structure according to an embodiment of the present invention;

[0070] Figure 6 This is a flowchart illustrating the overall process of designing the method according to an embodiment of the present invention.

[0071] Figure 7 This is a flowchart illustrating the overall construction method of an embodiment of the present invention.

[0072] In the diagram: 1. Sliding soil layer, 2. Stabilized soil layer, 3. Drill hole, 4. Steel pipe, 5. Anchor cable, 6. Cement mortar grouting body, 7. Cement concrete grouting body, 8. Connecting steel pipe, 9. Grouting hole, 10. First connector, 11. Second connector. Detailed Implementation

[0073] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0074] Figures 1-5 This invention illustrates a specific embodiment of a shear-resistant composite anchor cable based on local reinforcement of the sliding surface, comprising a composite shear-resistant section, an independent anchoring section, and a connecting steel pipe 8, wherein:

[0075] The composite shear-resistant section includes a steel perforated pipe 4, a cement mortar grouting body 6 filled within the steel perforated pipe 4, and an anchor cable 5 passing through it. The steel perforated pipe 4 covers the vertical thickness area of ​​the sliding soil layer 1 and extends 2 meters to both the inner and outer sides of the sliding soil layer. The vertical thickness of the sliding soil layer 1 is... The total length of the steel pipe 4 is The anchor cable 5 is bonded to the inner wall of the steel pipe 4 through the cement mortar injection body 6 to form a rigid composite; the cement mortar injection body 6 is made of M30 grade or higher micro-expansion cement mortar, and polypropylene fiber is added, with a fiber content of 0.8~1.2kg / m³; the steel pipe 4 has multiple injection holes 9 on its pipe wall, the opening rate of the injection holes 9 is 15%~20%, the hole diameter is 8~12mm, and the hole positions are distributed in an array;

[0076] The independent anchoring section is located in the stable soil layer 2 below the composite shear section and is formed by bonding the anchor cable 5 with the surrounding cement concrete grouting body 7.

[0077] The connecting steel pipe 8 is detachably connected to the upper end of the steel perforated pipe 4 via a connecting member, used for wall protection during hole drilling, and removed after grouting. The outer diameter of the connecting steel pipe 8 is equal to the inner diameter of the steel perforated pipe 4. The connecting member includes a first connecting member 10 fixedly installed inside the upper end of the steel perforated pipe 4 and a second connecting member 11 fixedly installed on the outer wall of the lower end of the connecting steel pipe 8, as shown below. Figure 3 As shown, the first connector 10 includes four spaced-apart first connecting pieces. The root of each first connecting piece is fixedly connected to the uppermost end of the opening of the steel pipe 4, and the first connecting pieces are inclined inward. Figure 4 As shown, the second connector 11 includes four second connectors that are spaced apart from the first connectors and have a matching shape. The root of the second connector is fixedly connected to the lowest end of the outer wall of the connecting steel pipe 8, and the second connector is tilted outward. The connecting steel pipe 8 and the steel flower pipe 4 are installed and disconnected by rotating 30°±5°.

[0078] Figure 6 This invention illustrates a specific embodiment of the shear-resistant composite anchor cable design method based on local reinforcement of the sliding surface described above, comprising the following steps:

[0079] Step S1: Basic Data Preparation and Stability Analysis

[0080] S1.1 Collect geological survey data: soil cohesion c and internal friction angle φ, groundwater level, and stratigraphic distribution;

[0081] S1.2 Determine the location of potential sliding soil layers using the Bishop method or finite element analysis;

[0082] S1.3 Calculate the sliding force by integrating along the sliding soil layer:

[0083]

[0084] In the formula, The sliding force per unit width of the slope (kN / m). The shear strength of the soil (kPa). This represents the actual shear stress (kPa) of the current sliding soil layer. is the length of a micro-segment of the sliding soil layer (m);

[0085] S1.4 Calculate the required total anti-skid force:

[0086]

[0087] In the formula, The required total anti-skid force (kN / m). For safety factors, a value of 1.25 to 1.50 (dimensionless) is typically used.

[0088] Step S2: Stress design of steel pipe:

[0089] S2.1 Determine the length:

[0090] =

[0091] In the formula, The design length (m) of the steel perforated pipe. The vertical thickness (m) of the potential sliding soil layer. The sum of the lengths (m) of the steel pipe extending into both the inner and outer sides of the sliding soil layer is taken in this embodiment. It is 4m;

[0092] S2.2 Calculate the sliding force in a single hole:

[0093]

[0094] In the formula, Design shear force (kN) for steel pipe. The horizontal spacing (m) between the steel pipes;

[0095] S2.3 Calculate the lateral force:

[0096]

[0097] In the formula, The lateral force (kN) acting on the steel pipe, α is the inclination angle of the sliding surface at the intersection of the anchor cable and the sliding surface (°), and β is the angle between the anchor cable and the horizontal plane (°), which should be downward inclined, generally between 10° and 30°;

[0098] S2.4, Condition 1, the steel pipe is subjected to lateral shear force (assuming the steel pipe is mainly subjected to shear):

[0099] Assume lateral force

[0100] Shear capacity verification:

[0101] In the formula, To design the shear force (N). The yield strength (MPa) of the steel pipe. The outer diameter of the steel flower pipe is (mm). The wall thickness of the steel pipe is (mm). The design value of shear strength of steel pipe is based on the Von Mises criterion (MPa).

[0102] S2.5, Working Condition 2, the cantilevered steel pipe is subjected to lateral force (assuming one end of the steel pipe is fixed):

[0103] Design bending moment

[0104] In the formula, M is the design bending moment (N·mm), and L is the distance (mm) from the point of application of the lateral force to the anchorage end, which should be determined according to the actual geological conditions.

[0105] Bending capacity verification:

[0106] In practice, first determine a set of outer diameter and wall thickness values ​​for the steel pipe based on empirical values. Then, perform the calculations according to the methods described in step S2.4 (shear capacity verification) and step S2.5 (bending capacity verification). If the requirements are not met, adjust the outer diameter and wall thickness values ​​until they are satisfied. In actual design, the failure of the cantilever steel pipe is controlled by the weaker of the bending and shear conditions. Bending failure usually occurs before shear failure, but for short and thick cantilever beams, the shear strength should be verified.

[0107] Step S3, Anchor Cable Tensile Design

[0108] S3.1 Axial tension of the anchor cable by downward force The calculation yields the following formula:

[0109]

[0110] In the formula: The axial tension of the anchor cable (N); The sliding force (N) within the range of a single anchor cable can be determined through landslide stability analysis. The reduction factor should be applied to soil slopes and loose, fractured rock slopes. The angle (°) of the sliding surface at the intersection of the anchor cable and the sliding surface; The angle (°) between the anchor cable and the horizontal plane should preferably be downward, generally between 10° and 30°; The internal friction angle of the sliding surface (°);

[0111] S3.2 The strength of the anchor cable must meet the following conditions:

[0112]

[0113] In the formula: This represents the net cross-sectional area (mm²) of the anchor cable strand. The tensile yield strength (MPa) of the anchor cable steel.

[0114] Figure 7 A specific implementation of the above-mentioned construction method for shear-resistant composite anchor cables based on local reinforcement of the sliding surface is shown, including the following steps:

[0115] Step S1: Drill holes in loose soil and simultaneously insert the combination of steel pipe 4 and connecting steel pipe 8 into the borehole 3;

[0116] Step S2: Remove residual soil from inside the steel pipe 4;

[0117] Step S3: Cable positioning, fix the anchor cable 5 in the center of the steel pipe 4;

[0118] Step S4: Grouting into borehole 3. First, inject cement concrete grout 7 to fill the hole of the independent anchoring section, and then inject cement mortar grout 6 to fill the inside of the steel pipe 4. The grouting pressure of the steel pipe section is ≥0.5MPa and held for 3min.

[0119] Step S5: After the cement mortar grouting body 6 inside the steel pipe 4 is filled, rotate the connecting steel pipe 8 to detach it from the steel pipe 4, and pull out the connecting steel pipe 8.

[0120] Step S6: Install the anchor and pressure plate at the opening of borehole 3;

[0121] Step S7: After the grout in borehole 3 reaches the design strength, tension the anchor cable 5 and lock it in place using anchors and pads. The anchor cable tensioning is carried out in three stages according to the design tension of 40%, 80%, and 110%.

Claims

1. A shear-resistant composite anchor cable with locally reinforced sliding surface, characterized in that, Includes a composite shear-resistant section, an independent anchoring section, and a connecting steel pipe (8), wherein: The composite shear section includes a steel pipe (4), a cement mortar grout (6) filled in the steel pipe (4), and an anchor cable (5) passing through it. The independent anchoring section is located below the composite shear section and is formed by bonding the anchor cable (5) with the surrounding cement concrete grouting body (7); The connecting steel pipe (8) is detachably connected to the upper end of the steel flower pipe (4) via a connecting member.

2. The shear-resistant composite anchor cable with locally reinforced sliding surface according to claim 1, characterized in that: The steel pipe (4) has multiple grouting holes (9) on its wall.

3. The shear-resistant composite anchor cable with locally reinforced sliding surface according to claim 1, characterized in that: The cement mortar injection body (6) uses M30 grade or higher micro-expansion cement mortar and adds polypropylene fiber, with a fiber content of 0.8~1.2kg / m³.

4. The shear-resistant composite anchor cable with locally reinforced sliding surface according to claim 1, characterized in that: The connecting component includes a first connector (10) fixedly installed inside the upper end of the steel pipe (4) and a second connector (11) fixedly installed on the outer wall of the lower end of the connecting steel pipe (8). The first connector (10) includes multiple first connecting pieces spaced apart, and the second connector (11) includes multiple second connecting pieces spaced apart and with matching shapes to the first connecting pieces.

5. A design method for a shear-resistant composite anchor cable with locally reinforced sliding surface, applied to the shear-resistant composite anchor cable as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Basic Data Preparation and Stability Analysis: Calculate the sliding force: ; In the formula, The sliding force per unit width of the slope. For soil shear strength, This represents the actual shear stress of the current sliding soil layer. This refers to the length of a micro-segment of the sliding soil layer; Calculate the total anti-skid force required: ; In the formula, For the required total anti-skid force, For safety factor; S2. Stress design of steel perforated pipe: S2.1 Determine the length: ； In the formula, Design length for steel perforated pipe, The vertical thickness of the potential sliding soil layer. It is the sum of the lengths of the steel pipe extending to both the inner and outer sides of the sliding soil layer; S2.2 Calculate the sliding force in a single hole: ； In the formula, Design shear force for steel pipe. This refers to the horizontal spacing between the steel pipes; S2.3 Calculate the lateral force: ； In the formula, The lateral force acting on the steel pipe is α, where α is the inclination angle of the sliding surface at the intersection of the anchor cable and the sliding surface, and β is the angle between the anchor cable and the horizontal plane. S2.4, Condition 1, the steel pipe is subjected to lateral shear force: Assume lateral force ; Shear capacity verification: ; In the formula, To design shear force, For the yield strength of the steel pipe, The outer diameter of the steel pipe. For steel pipes with thick walls, This is the design value for the shear strength of the steel perforated pipe; S2.5, Condition 2, the cantilevered steel pipe is subjected to lateral force: Design bending moment ; In the formula, M is the design bending moment, and L is the distance from the point of application of the lateral force to the anchorage end; Bending capacity verification: ; S3, Anchor cable tensile design S3.1 Axial tension of the anchor cable by downward force The calculation yields the following formula: ； In the formula: For the axial tension of the anchor cable, This refers to the sliding force within the range of a single-hole anchor cable. This is the reduction factor. The angle of inclination of the sliding surface at the intersection of the anchor cable and the sliding surface. The angle between the anchor cable and the horizontal plane. The friction angle within the sliding surface; S3.2 The strength of the anchor cable must meet the following conditions: ； In the formula: The net cross-sectional area of ​​the anchor cable strand. This refers to the tensile yield strength of the anchor cable steel.

6. A construction method for a shear-resistant composite anchor cable with locally reinforced sliding surface, applied to the shear-resistant composite anchor cable as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Step S1: Drill holes in loose soil and simultaneously insert the combination of steel pipe and connecting steel pipe into the borehole; Step S2: Remove residual soil from inside the steel pipe; Step S3: Cable positioning, fix the anchor cable in the center of the steel pipe axis; Step S4: Grouting into the borehole. First, inject cement concrete grout to fill the hole of the independent anchoring section, and then inject cement mortar grout to fill the inside of the steel pipe. The grouting pressure of the steel pipe section is ≥0.5MPa and held for 3 minutes. Step S5: After the cement mortar grouting inside the steel pipe is filled, rotate the connecting steel pipe to detach it from the steel pipe and pull out the connecting steel pipe. Step S6: Install anchors and pressure-bearing plates at the borehole opening; Step S7: After the grout in the borehole reaches the design strength, tension the anchor cable and lock it in place using anchors and pads. The anchor cable tensioning is carried out in three stages according to the design tension of 40%, 80%, and 110%.

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