Explosion expanded internal anchor head prestressed anchor cable for strengthening weak rock and anchoring method thereof

Abstract

The invention discloses an explosion expanded internal anchor prestressed anchor cable for strengthening a weak rock and an anchoring method thereof. The anchor cable comprises a bit expanded anchor cable hole and an anchor cable body with an explosion expanded internal anchor head, wherein the explosion expanded internal anchor head consists of a lantern-shaped steel frame and a grouting body; and the lantern-shaped steel frame comprises lanced steel tubes, wire meshes and detached steel strands which are hierarchically distributed from the interior to the exterior. The anchoring method comprises the following steps of: drilling an anchor cable hole by using a driller, putting explosive at the bottom of the hole for explosion after holing, cleaning the hole and making a spherical cavity formed at the bottom of the drilled hole; simultaneously making an initial sample of the explosion expanded internal anchor head anchor cable by using the steel strands, the steel tubes, the wire meshes, the explosive and the like, inserting the anchor cable, igniting the explosive in the initial sample of the anchor cable, and forming the lantern-shaped internal anchor head steel frame; and finally grouting, and stretching and locking the anchor cable. The invention can obviously improve the bearing capacity of the internal anchor head grouting body and the prestress of the anchor cable, effectively solves the problem of poor anchored force of the anchor cable in the process of strengthening the weak rock, and can shorten the length of the internal anchoring section and widen an effective range of anchoring the rock.

Description

technical field [0001] The invention belongs to the technical field of geotechnical reinforcement engineering, and in particular relates to a prestressed anchor cable with an explosive expansion inner anchor head for reinforcing weak rock mass and an anchoring method thereof. Background technique [0002] In geotechnical reinforcement engineering, prestressed anchor cables are commonly used support types. The existing prestressed anchor cable structure is usually drilled by a drilling rig, and the end of the anchor cable is cemented in the rock mass by cement mortar and other materials at the bottom of the cylindrical borehole, and the free section of the anchor cable in the hole is stretched to make the anchor cable appear Tensile prestressing makes the rock mass within a certain range around the anchor cable hole in a state of compression, increases its strength, and thus achieves the purpose of strengthening the rock mass. At present, ordinary anchor cables, prestressed ...

AI Technical Summary

Problems solved by technology

[0007] (1) When the pressure-type anchor cable is used, when the tensile load of the anchor cable is too large, the grouting body may be crushed and the anchor cable is pulled out; when the tension-type anchor cable is used, the grouting body is prone to cracking and shearing destroy

[0008] (2) The mechanical drilling method can generally only form cylindrical drilling holes. When the rock mass is relatively weak (such as strongly weathered granite), the joint surface between the grouting body and the rock mass in the anchorage section of the anchor cable is prone to shear failure. The prestressed design tonnage cannot be reached when the cable is stretched

[0009] (3) In order to provide greater anchoring force, the length of the inner anchorage section of the anchor cable is longer, even reaching half of the total length of the anchor cable, resulting in a smaller length of the free tension section of the anchor cable, and the actual range of anchored rock mass is limited. unreasonable structure

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