武当群片岩隧道剪切型纵向裂缝破坏机理

摘要

根据现场隧道监控测量数据分析武当群片岩隧道变形破坏特征,利用Phase2.Turnel有限元软件与实际监测结果相对比的方式,从围岩岩性特征,构造应力和片理面力学性质3个方面,探究十房高速公路通省特长隧道拱顶纵向裂缝形成机理.研究结果表明:该围岩不含蒙脱石,伊利石质量分数同样较低,因此,围岩内部膨胀力的作用可忽略；由于片理面的存在,拱顶两侧围岩发生差异破坏,片理面较低的抗剪强度是导致纵向裂缝的内在因素,其产状控制纵向裂缝的发生位置；随着片理面间距的减小,拱顶右侧产生类似偏压形成的拉伸破坏,是控制纵向裂缝次生裂缝的主导因素；而侧压力系数λ≥1.0的地质构造环境是产生该裂缝的诱发因素.%The monitoring measuring data revealed the deformation and failure mechanism of Wudang group of schist.The adhesive elastic finite element method and monitoring result are compared to explore the formation mechanism of vault longitudinal cracks in Tongsheng tunnel.The results show that the Montmorillonite content in surrounding rock is close to zero,and illite is low too,so the internal force of expansion of surrounding rock function may be ignored.The simulation result shows that:because of the existence of weak foliation of schist,there are significant differences in destruction features of both sides vault surrounding rock; low shear strength in foliation is the internal factors of longitudinal cracks,and the attitude of schistosity plane has effective control over the cracks position.With the reduction of schistosity plane space,the failure mode of right vault surrounding rock tums compression into tensile failure,seemingly caused by unsymmetrical load.And the influence degree of the longitudinal cracks will be intensified when the rock-mass in the geological environment λ≥ 1.0,and the greater the degree,the more serious the impact is.