CN-121992775-A - Shear-resistant composite anchor cable with locally reinforced sliding surface and design and construction methods thereof

Abstract

The shearing-resistant composite anchor cable mainly comprises a composite shearing-resistant section, a shearing-resistant section and a shearing-resistant section, wherein the composite shearing-resistant section comprises a steel flower pipe, a cement mortar grouting body filled in the steel flower pipe and an anchor cable penetrating through the steel flower pipe; the independent anchoring section is positioned below the composite shearing-resistant section and is formed by bonding an anchor cable and surrounding cement concrete grouting bodies, and the connecting steel pipe is detachably connected to the upper end of the steel pipe through a connecting member. The invention can improve the defects of insufficient shearing capacity and easy stress concentration at the end of the existing loose soil mass slope anchoring structure, obviously improves the shearing resistance through a local composite reinforcing means, realizes shearing resistance-tensile dual reinforcement through the cooperative work of the composite shearing resistance section and the independent anchoring section, and saves the steel consumption compared with the traditional permanent sleeve scheme through recovering the connecting steel pipes.

Inventors

• Zhu Linze
• CHI XUEXIN
• LIAO JIN
• HE ANJING
• ZHONG SHAOJUN
• JIN HONGTAO
• SHEN FENG
• LI JIAN
• LI SHUMING
• HE DONGJIN
• ZHANG JIANSHU
• MENG DUO
• ZENG XIAOBO
• Long Zongming
• SONG MING
• MA XIAOLONG
• WU ZHIHUA
• LI CHUNXIA

Assignees

• 中铁二院(成都)建设发展有限责任公司

Dates

Publication Date

20260508

Application Date

20251226

Priority Date

20250926

Claims (6)

1. 1. The shear-resistant composite anchor cable with the locally reinforced sliding surface is characterized by comprising a composite shear-resistant section, an independent anchoring section and a connecting steel pipe (8), wherein: The composite shearing-resistant section comprises a steel flower pipe (4), a cement mortar grouting body (6) filled in the steel flower pipe (4) and an anchor cable (5) penetrating through the steel flower pipe; The independent anchoring section is positioned below the composite shearing-resistant section and is formed by bonding an anchor cable (5) and a surrounding cement concrete grouting body (7); The connecting steel pipe (8) is detachably connected to the upper end of the steel flower pipe (4) through a connecting component.
2. 2. The shear-resistant composite anchor cable with the locally reinforced sliding surface, as claimed in claim 1, is characterized in that a plurality of grouting holes (9) are formed in the wall of the steel flower pipe (4).
3. 3. The shear-resistant composite anchor cable with the locally reinforced sliding surface, which is disclosed in claim 1, is characterized in that the cement mortar grouting body (6) adopts micro-expansion cement mortar with the level of M30 or more, and is doped with polypropylene fibers, and the fiber doping amount is 0.8-1.2 kg/M < 3 >.
4. 4. The shear composite anchor cable with locally reinforced sliding surface according to claim 1, wherein the connecting component comprises a first connecting piece (10) fixedly installed in an orifice at the upper end of the steel pipe (4) and a second connecting piece (11) fixedly installed on the outer wall of the orifice at the lower end of the connecting steel pipe (8), the first connecting piece (10) comprises a plurality of first connecting pieces arranged at intervals, and the second connecting piece (11) comprises a plurality of second connecting pieces which are correspondingly arranged at intervals with the first connecting pieces and are adaptive in shape.
5. 5. The design method of the shear-resistant composite anchor cable with the locally reinforced sliding surface is applied to the shear-resistant composite anchor cable according to any one of claims 1 to 4, and is characterized by comprising the following steps: S1, basic data preparation and stability analysis: Calculating the sliding force: ; in the formula, Is the sliding force of the unit width of the side slope, Is the shear strength of the soil body, For the actual shear stress of the current sliding soil layer, The length of the soil layer micro-segment is sliding; Calculating the required total slip resistance: ; in the formula, In order for the total slip resistance to be required, Is a safety coefficient; s2, stress design of the steel flower pipe: S2.1, determining the length: ; in the formula, The length of the steel floral tube is designed, For a potential sliding of the vertical thickness of the soil layer, The length of the steel pipe extending to the inner side and the outer side of the sliding soil layer is the sum of the lengths; s2.2, calculating a single Kong Xiahua force: ; in the formula, The shearing force is designed for the steel floral tube, Is the horizontal spacing between the steel flower pipes; S2.3, calculating lateral force: ; in the formula, For the lateral force acting on the steel flower pipe, alpha is the inclination angle of the sliding surface at the intersection of the anchor cable and the sliding surface, and beta is the included angle between the anchor cable and the horizontal plane; s2.4, working condition 1, wherein the steel flower pipe is subjected to lateral shearing force: With lateral force ; Checking and calculating the shearing bearing capacity: ; in the formula, In order to design the shear force, Is the yield strength of the steel floral tube, Is the outer diameter of the steel floral tube, Is the wall thickness of the steel floral tube, The design value of the shear strength of the steel floral tube is designed; S2.5, working condition 2, the cantilever steel flower pipe is stressed by lateral force: Design bending moment ; Wherein M is a design bending moment, L is the distance from the lateral force acting point to the anchoring end; and checking bending bearing capacity: ; s3, tensile design of anchor cable S3.1 axial tension of anchor cable By the sliding force The formula is calculated as follows: ; Wherein: For the axial tension of the anchor cable, For a sliding down force in the range of single Kong Maosuo, In order to reduce the coefficient of the refraction, For the inclination angle of the sliding surface at the intersection of the anchor cable and the sliding surface, Is the included angle between the anchor cable and the horizontal plane, Is the internal friction angle of the sliding surface; s3.2, the strength of the anchor cable needs to meet the following conditions: ; Wherein: Is the net cross-section area of the anchor cable steel strand, Is the tensile yield strength of the anchor cable steel.
6. 6. The construction method of the shear-resistant composite anchor cable with the locally reinforced sliding surface, which is applied to the shear-resistant composite anchor cable according to any one of claims 1 to 4, is characterized by comprising the following steps: Step S1, forming holes in loose soil, and synchronously placing a combination of a steel flower pipe and a connecting steel pipe into the drilled holes; s2, removing residual soil in the steel flower pipe; S3, threading and positioning, and centering and fixing the anchor cable on the axle center of the steel flower pipe; s4, grouting into the drilled hole, firstly injecting cement concrete grouting body to fill the holes of the independent anchoring sections, and then injecting cement mortar grouting body to fill the inside of the steel flowtube, wherein the grouting pressure of the steel flowtube section is more than or equal to 0.5MPa and is maintained for 3min; s5, after filling of cement mortar grouting body in the steel floral tube is completed, rotating the connecting steel tube to separate the connecting steel tube from the steel floral tube, and pulling out the connecting steel tube; S6, installing an anchor and a pressure bearing backing plate at the hole opening of the drilled hole; and S7, stretching the anchor cable after the grouting body in the drilled hole reaches the design strength, locking and anchoring the anchor cable through an anchorage device and a backing plate, and carrying out three-stage loading on the anchor cable according to the design pulling force of 40%, 80% and 110%.

Description

Shear-resistant composite anchor cable with locally reinforced sliding surface and design and construction methods thereof Technical Field The invention relates to the technical field of geotechnical engineering side slope reinforcement, in particular to a shear-resistant composite anchor cable with a locally reinforced sliding surface and a design and construction method thereof. Background In the rock-soil slope anchoring engineering, the traditional prestressed anchor cable relies on the bonding of a grouting body and a soil body to transfer tension, but has serious mechanical defects in a potential sliding soil layer area. The sliding belt is used as a shear deformation concentration area, the shear stress born by the anchor cable can reach 3-5 times of that of a non-sliding soil layer area, and the shear strength of the cement-based grouting body is usually less than 5MPa, so that brittle shear damage is easy to occur. This problem is particularly pronounced in loose soil slopes where the low cohesion (c <20 kPa) and high rheology make the grouting body-soil interface bond strength less than 30% of the rock mass, resulting in near 70% of anchor failure cases manifested as grouting body cracking or interface slip in the sliding soil layer area. The existing enhancement measures have the remarkable limitations that the diameter or density of the anchor cable is increased, the overall tensile capacity is improved, the local stress concentration is increased, the engineering cost is increased by more than 40%, the local protection of the steel sleeve is adopted to delay the shearing damage, but the slurry-soil bonding area is sacrificed by more than 80%, and the effective transmission of the prestress is prevented. The fundamental contradiction is that the mutual exclusion of the tensile and shear properties-strengthening tensile strength amplifies the shear peak, while the rigid shear member weakens the system's ability to cooperatively deform. Particularly, under rainfall or earthquake dynamic load, repeated shearing and expanding effects of loose soil bodies accelerate fatigue damage of grouting bodies, so that the failure rate of the traditional anchor cable is as high as 15-25%. The prior art has not solved the dual requirements of distributing type dissipation shear stress and maintaining integral bonding integrity of a sliding soil layer region, and has urgently needed to develop a novel composite anchor cable structure, and the shear stress redistribution and multistage energy consumption are realized by implanting shear-resistant units coupled with a inhaul cable body in a sliding belt, so that the shear rigidity and ductility of a system are synchronously improved, and the long-term technical bottleneck in the field of rock-soil anchoring is fundamentally broken through. Disclosure of Invention The invention aims to provide a shear-resistant composite anchor cable which remarkably improves the shear resistance through local composite reinforcement and a design construction method aiming at the defects of insufficient shear resistance and easy stress concentration at the end part of a loose soil mass slope anchoring structure. The invention adopts the technical scheme that the shear-resistant composite anchor cable with the locally reinforced sliding surface comprises a composite shear-resistant section, an independent anchoring section and a connecting steel tube, wherein: The composite shearing-resistant section is positioned in a potential sliding soil layer area of the side slope and comprises a steel flower pipe, a cement mortar grouting body filled in the steel flower pipe and an anchor rope penetrating through the steel flower pipe, wherein the steel flower pipe covers a vertical thickness area of the sliding soil layer and extends a certain length to the inner side and the outer side of the sliding soil layer respectively, the sliding soil layer is ensured to be completely covered, the stress is fully diffused, the shearing force is effectively transferred and the stress concentration at the end part is avoided, the cement mortar grouting body realizes full-section filling in the steel flower pipe, the anchor rope is bonded with the inner wall of the steel flower pipe through the cement mortar grouting body to form a rigid composite body, and the anchor rope is completely wrapped and embedded; The independent anchoring section is positioned below the composite shearing-resistant section, extends into a stable soil layer or a rock stratum, is bonded with surrounding cement concrete grouting bodies to form a conventional anchoring body, and mainly provides tensile resistance, and the anchor cable can be protected by a sleeve in the section; the connecting steel pipe extends to the slope surface, the connecting steel pipe is detachably connected to the upper end of the steel pipe through the connecting component, the connecting steel pipe is synchronously placed in the soil body when holes ar