Anchoring effect and energy-absorbing support mechanism of large deformation bolt

Abstract

To research the anchoring effect of large deformation bolt, tensile and drawing models are established. Then, the evolution laws of drawing force, bolt axial force and interfacial shear stress are analyzed. Additionally, the influence of structure element position on the anchoring effect of large deformation bolt is discussed. At last, the energy-absorbing support mechanism is discussed. Results show that during the drawing process of normal bolt, drawing force, bolt axial force and interfacial shear stress all gradually increase as increasing the drawing displacement, but when the large deformation bolt enters the structural deformation stage, these three values will keep stable; when the structure element of large deformation bolt approaches the drawing end, the fluctuation range of drawing force decreases, the distributions of bolt axial force and interfacial shear stress of anchorage section are steady and the increasing rate of interfacial shear stress decreases, which are advantageous for keeping the stress stability of the anchorage body. During the working process of large deformation bolt, the strain of bolt body is small, the working resistance is stable and the distributions of bolt axial force and interfacial shear stress are steady. When a rock burst event occurs, the bolt and bonding interface cannot easily break, which weakens the dynamic disaster degree.