针对锚索在本身预应力及动荷载作用下轴向力可能产生损失、降低抵抗洞室变形能力的问题,采用有限差分数值分析方法,通过构造简单洞室模型,分别对简化的地震动载荷进行纵向压缩、横向剪切数值模拟.结果表明:由于洞室尺寸相对于无限空间较小,动载荷作用时洞室几何形状引起的挠动有限,因此锚索内动应力引起的变化较小;锚索安装角对该作用力的大小有很大影响;波动频率越高,该作用力越大;波动的类型影响不大.
With regard to the potential decrease of the axial force of anchor cables and the resulting reduction of deformation resisting capacity of tunnels under their inherent stress and dynamic load,the finite different method was adopted.Based on a round tunnel model,the simplified dynamic seismic load of the tunnel supported by prestressed anchor cables was simulated under pressure waves and shear waves separately.The results show that because the tunnel dimension is far smaller than the infinite space,the seismic load leads to limited torsion of the tunnel,so the stress of the cables has small variation.The angle of the cables has great influences on the stress.The higher the earthquake frequency is,the larger the force is.The propagation type has few influences.