Research on Full-Section Anchor Cable and C-Shaped Tube Support System of Deep Layer Roadway

Abstract

Deep roadway deformation due to soft rock, rock dip, and horizontal tectonic stress is uneven and asymmetrical primarily in large loose zones. Traditional anchor support is influenced by the yield strength and shear strength of the anchors and has a limited prestress capacity or shear resistance. When the roadway roof is laminated rock or when the roadway passes through layered rock or rock interfaces, interlayer sliding commonly occurs, which can easily lead to anchor cables being sheared off. The tape tunnel in the Zhengling Mine passes through several rock strata and requires anchors to achieve a high shear resistance and prestress. To solve these problems, an anchor cable and C-shaped tube that can bear lateral shear forces were developed, and a full-section anchor cable and C-shaped tube support system were created based on extruded arch theory. Numerical results from FLAC3D show that the new scheme effectively controls surface convergence and plastic zone extension. Field tests have demonstrated that the amount of surface displacement was at least 42% smaller in the new support scheme. The extruded arch formed by the highly prestressed anchor cable and concrete spray layer can effectively control the bulking load within the loose zone, and the ACC effectively resists interlayer shear.

Research on the deformation mechanism and ACC control technology of gob‐side roadway in an extra‐thick coal seam with varying thickness

“…The C‐shaped steel tube is nested in the free section of the anchor cable that corresponds to the shallow crushing area of the surrounding rock, which can improve the shear stiffness and strength of the anchor cable in this area. Its effect has been proven by a large number of laboratory tests 35,36 . Therefore, this structure has a high bearing capacity and displacement control ability in both axial direction and tangential direction.…”

“…Its effect has been proven by a large number of laboratory tests. 35,36 Therefore, this structure has a high bearing capacity and displacement control ability in both axial direction and tangential direction. Shallow crushing surrounding rock can be better reinforced, so that its stress state can be effectively improved, and the overall strength can be enhanced.…”

“…During the process of deformation and failure of the surrounding rock, lateral displacement and shear expansion of the surrounding rock are very common phenomena, 32,33 resulting in frequent breakage of anchor bolts and cables. Therefore, the research team has invented a new type of support structure called “Anchor Cable with C‐shaped Tube (ACC)”, which not only ensures the high axial bearing capacity of the support components, but also significantly improves the tangential bearing capacity 34–36 . At present, ACC has been successfully applied in roadway support in more than 10 coal mines in China.…”

“…Therefore, the research team has invented a new type of support structure called "Anchor Cable with C-shaped Tube (ACC)", which not only ensures the high axial bearing capacity of the support components, but also significantly improves the tangential bearing capacity. [34][35][36] At present, ACC has been successfully applied in roadway support in more than 10 coal mines in China. By utilizing ACC and combining the deformation and failure characteristics and principles of roadway, targeted control strategies and optimized support schemes are proposed.…”

Research on Anchor Cable and C‐Shaped Tube Support Method in Deep Layers Roadway, Experimental Study, and Numerical Simulation

“…ACC adds a C-shaped tube to the outer side of the cable bolt (Figure 2). C-shaped tube is a steel tube with a 15 °straight gap on the side [21].…”