锚杆对围岩的加固效果和动载响应的数值分析

利用数值分析软件LS-DYNA3D程序，对锚杆对围岩的加固效果和动态力学性能进行了显示动力分析，比较了洞室围岩是否用锚杆加固时，爆炸波引起的岩体中垂直应力、拱顶位移以及锚杆本身轴向应变的变化特点。结果发现：同毛洞相比较，加固洞室围岩应力较大，拱顶位移较小；通过分析锚杆轴向应变-时程曲线，发现不同安装角的锚杆其轴向应变对动载的响应不同，拱部锚杆先受压后受拉，直墙部锚杆全受拉，两部位锚杆均产生轴向拉应变；将模拟的锚杆应变-时程曲线同模型试验的相应曲线进行了比较，两者一致性较好，其结果为动载作用下坑道围岩锚杆加固的布置方法提供了参考。

Numerical analysis of reinforcement effects and response to dynamic loads characteristics of rock bolts

The explicit dynamic analysis of the reinforcement effects and dynamic characteristics of rock bolts is carried out by LS-DYNA software. The change features of vertical stress of rockmass, vault displacement and axial strain of rock bolts themselves caused by explosive waves are compared whether wall rock is reinforced or not. By comparing the cavern that is not reinforced, the stress of wall rock is larger and the displacement of vault is less than the cavern that is reinforced by rock bolts. By analyzing the axial strain temporal curves of rock bolts, the response to the dynamic loads is different when rock bolts’ installing angles are different. The rock bolts of vault bear pressure at first and tension after., and the rock bolts in upright wall bear tension absolutely. The axial tension strain generates at these two positions. The comparison between the axial strain temporal curves and the corresponding curves is carried out in model test. These two curves are compatibility. This simulation provides the references of arrangement methods in wall rock of tunnels reinforced by rock bolts under the effect of dynamic loads.