论文部分内容阅读
以地下洞室全长粘结式锚杆为研究对象,分析了锚杆与围岩荷载传递机制,导出了相应的荷载传递基本微分方程.结合围岩自由变形,采用有限差分法求解方程,进而得到锚固体轴力和界面剪应力沿杆长分布.采用二折线剪切滑移模型描述锚固体界面力学特性,考虑锚固体滑移,将界面的超余剪应力转化为模型节点荷载,通过不断更新围岩位移以修正锚固体内力.基于此锚杆算法,模拟了拉拔试验,结果表明该方法合理、可行.通过对某引水隧洞特征锚杆的受力分析,计算了围岩弹模、界面剪切刚度、砂浆厚度、锚杆直径和锚杆长度对锚固体受力的影响,计算结果可为地下洞室锚杆布置优化提供理论依据.
Taking the full-length underground cavern bonded rock bolt as the research object, the load transfer mechanism between the rock bolt and the surrounding rock is analyzed and the corresponding basic differential equation of load transfer is deduced. Combined with the free deformation of the surrounding rock, the finite difference method is used to solve the equation The axial force and interfacial shear stress distribution of the anchor are distributed along the length of the rod. The second-slip shear-slip model is used to describe the mechanical properties at the interface of the anchor. Considering the slipping of the anchor, the excess shear stress at the interface is transformed into the model node load. The displacement of the surrounding rock is updated to correct the internal force of the anchor. Based on this anchor algorithm, the pullout test is simulated and the results show that the method is reasonable and feasible.Based on the mechanical analysis of the characteristic rock bolt of a diversion tunnel, The effect of interface shear stiffness, thickness of mortar, bolt diameter and anchor length on the stress of anchor is analyzed. The calculation results can provide the theoretical basis for the optimization of anchor layout in underground caverns.