节理特征对破碎围岩稳定性影响的模型试验

Model Test of Effect of Joint Characteristics on Stability of Broken Rock Mass

根据隧道围岩节理发育特征,采用相似比为1∶50的试验模型研究节理特征对隧道开挖围岩稳定性的影响。试验研究了不同倾角、不同间距、多组节理情况下隧道开挖后围岩的塌落范围及松动范围。试验研究表明:随着节理倾角的增加,围岩稳定性先变好,而后变差,当节理倾角为45°～60°之间时,围岩稳定性最好;当节理间距由0.5 m变为0.75 m时,隧道围岩稳定性变好,围岩塌落面积最大减少44.7%,塌落高度最大减少24.8%,松动区最大位移最大减少32.9%;多组节理情况下,较单组节理情况围岩稳定性明显变差,围岩塌落范围及松动范围明显增大,且节理间距小的一侧塌落范围较大。

According to the tunnel surrounding rock joint characteristics, using the test model with 1：50 similarity ratio to research the effect of joint characteristics on surrounding rock stability of tunnel under excavation. The collapsing range and the looseness area of surrounding rock after tunnel excavation in different joint inclination angles, different joint spacings, and multi-set of joints are experimental researched. The experiment result shows that （ 1 ） with the increase of joint inclination angle, the stability of surrounding rock changed better then worse, the stability of surrounding rock is most stable when joint inclination angle ranges from 45. to 60.; （2） when the joint spacing changes from 0.5 m to 0.75 m, the stability of surrounding rock became better, the greatest reduction in collapsing area of surrounding rock is 44. 7%, the greatest reduction in collapsing height is 24. 8%, the greatest reduction in maximum displacement of looseness range is 32.9% ; （3） in case of multi-set of joints, the stability of surrounding rock became much worse, and the collapsing range and looseness range of surrounding rock increased significantly compared with the situation which it has a set of joints, and the collapsing range is larger in joint spacing on the small side.