基于能量增减法的深埋绿片岩隧洞稳定性评价方法

Stability estimation method of greenschist tunnel based on increasing-decreasing energy method

基于对现场地质条件和开挖响应的直观认识和对岩石室内试验所得物理力学特性的深刻揭示,建立了深埋条件下软弱围岩大变形挤压程度分级方法及相对应的安全系数计算方法。该方法考虑到隧洞原岩集聚的能量过大是造成开挖后围岩失稳的根本原因,将隧洞原岩能量和围岩的总变形与弹性变形之比相结合,分析了隧洞的围岩稳定性状况,并在此基础上通过增减隧洞原岩能量得到了其安全系数。通过实际工程应用及与传统经验评价方法的对比,验证了该方法的合理性与适用性。该方法考虑了围岩的地质情况、断面形状、尺寸、开挖方式等多种因素,弥补了传统经验评价方法无法适应复杂多变的现场工程施工情况的不足,更加贴近实际。可为大变形隧洞的安全预测、开挖方案、支护设计等提供重要参考依据。

Based on the understanding of geological conditions,tunnel excavation response and the physico-mechanical properties from laboratory tests of rock,deformation gradation and safety factor of the soft rock tunnel are proposed.Considering that the root cause of tunnel instability after excavation is the excessive energy of the tunnel native rock;the energy,which is combined with the ratio of the total deformation and elastic deformation,is used to analyze the stability of the tunnel;and on the basis,the safety factor is obtained by increasing-decreasing energy of the original rock.Through the practical application and compared with traditional evaluation methods,the method metioned above is proved to be reasonable and practical.The geological conditions of surrounding rock,the cross section shape,size,excavation and other factors,which are rarely considered by traditional evaluation methods are taken into account,so as to supply important references for the underground engineering.