剪切荷载作用下锚杆抗剪作用理论分析

为了分析剪切过程锚杆轴力和横向剪切力相对结构面换算的抗剪贡献影响程度,在经典梁理论的基础上,推导了锚杆抗剪力计算公式,并采用加锚结构面直剪试验验证了计算公式的可靠性。在此基础上,通过正交试验设计方法研究影响因素对锚杆轴力、横向剪切力相对结构面抗剪贡献的敏感程度。结果表明:锚杆抗剪理论计算与室内试验结果吻合较好;锚杆倾角是影响锚杆轴力相对结构面换算抗剪力的主要因素;锚杆需要一定变形才能调动起直径对轴力抗剪效应的影响;锚杆倾角是影响横向剪切力相对结构面换算抗剪力的最主要因素,围岩强度次之,剪切后期结构面剪胀系数的影响程度又大于围岩强度;直径对锚杆横向剪切力相对结构面换算抗剪力的影响程度最小。

Theoretical Analysis on Shear Resistance of Bolt under Shear Loading

According to the shear resistance of the bolted joint contributed by the axial force and transverse shear force, based on the classical beam theory, the formulas of shear strength of bolted joint are deduced. The reliability of theoretical solutions is verified by direct shear test with bolted structure. Influence extent and law of various factors on the shear resistance is performed based on the orthogonal design. The results show that the theoretical results is in good agreement with the test results; The bolt inclination is a major factor on the shear resistance of joint contributed by the axial force; A certain deformations of bolt can arose the effect of bolt diameter on shear resistance of joint contributed by the axial force; Among the factors on shear resistance of joint contributed by the transverse shear force, the bolt inclination first, and rock mass strength second, however, in the late period of shearing, the effect of dilatancy coefficient is larger than the effect of rock mass strength; The bolt diameter has least influence on the shear resistance of joint contributed by the transverse shear force.