挤压性围岩隧道大变形机理及分级标准研究

Mechanism and classification criterion for large deformation of squeezing ground tunnels

结合高地应力条件下挤压性大变形隧道——乌鞘岭隧道工程实例,通过变形的现场量测结果,分析了挤压性围岩隧道大变形的基本特征。采用室内试验及现场量测等手段,综合分析确定了围岩物理力学参数,定量分析了洞室周边产生塑性区的条件、塑性区及洞壁位移的影响因素、塑性区半径与洞壁位移的关系。以现场量测数据为依托,结合理论计算,参考以往类似隧道经验,分别考虑了围岩的相对变形、强度应力比、原始地应力、弹性模量作为分级指标,并提出了综合系数α指标,采用综合指标判定法给出了大变形的分级标准,以及相应的防治措施。

Based on a practical project of Wushaoling tunnel, a squeezing ground tunnel with high geostress conditions, the essential characteristics of squeezing ground tunnels were analyzed according to the monitored data. In terms of laboratory tests and in-situ monitoring, the physical and mechanical parameters of surrounding rock were synthetically established and analyzed The condition for the generation of plastic zone arround tunnels, the influencing factors of plastic zone and displacement of tunnels and the relationship between radius of plastic zone and displacement of tunnel were quantitatively analyzed. Based on the monitored data, theoretical calculation and experience of similar tunnels, considering relative deformation, strength stress ratio, ground stress, elastic ratio and comprehensive coefficient o~ as classification indexes, the classification criterion and measures to prevent large deformation of squeezing ground tunnels were worked out.