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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 characteristics of the joint development of the surrounding rock of the tunnel, a test model with similar ratio 1:50 is used to study the influence of the joint characteristics on the stability of the surrounding rock of tunnel excavation. The range of collapse and looseness of surrounding rock after tunnel excavation under different pitching angles, different pitches and multiple sets of joints are studied experimentally. The experimental results show that the stability of surrounding rock becomes better and then becomes worse with the increase of dip angle. When the dip angle is between 45 ° and 60 °, the stability of surrounding rock is the best. When the joint spacing increases from 0.5 m to Is 0.75m, the stability of surrounding rock of tunnel becomes better, the maximum slump area of rock mass decreases by 44.7%, the maximum slump height decreases by 24.8%, and the maximum displacement of loosening area decreases by 32.9%. Under multi-joint conditions, In the case of the surrounding rock, the stability of the surrounding rock is significantly deteriorated, the range of rock collapse and the range of looseness obviously increase, and the range of collapse on the small side of the joint spacing is larger.