山岭隧道洞口段围岩变形特征分析

Characteristics Analysis about Surrounding Rock Deformation of Entrance Section in Mountain Tunnel

为了研究山岭隧道洞口段围岩变形特征,以贵州省晴隆-兴义高速公路登攀隧道为工程依托,对洞口段围岩变形展开研究,通过对现场围岩变形进行监测和数据处理,分析了山岭隧道洞口段围岩变形的时间与空间效应,进而对山岭隧道洞口段围岩变形时间特征和空间特征展开研究。研究结果表明:隧道开挖引起围岩变形具有明显的时间效应和空间效应,监测断面围岩变形在开挖后历经8 d和27 m^30 m后稳定;山岭隧道洞口段围岩变形具有明显的空间特征,周边收敛值在时间轴上规律性较差,但累计变形量较小,对隧道围岩稳定性影响有限;洞口段拱顶沉降与地表沉降时间历程曲线有明显的规律,但累计变形量、分布特征与围岩本身属性紧密相关,地域差异性较大。

In order to research the characteristics of surrounding rock deformation at entrance section in mountain tunnel,based on Dengpan tunnel of Qinglong-Xingyi expressway in Guizhou province,the deformation of surrounding rock at entrance of the tunnel is studied. The time and space effect of the deformation were analyzed through processing monitoring data. For the monitoring section behind the excavation section at a distance of 27 ～ 30 m,the deformation of surrounding rock becomes stable after eight days. The surrounding rock deformation at entrance of mountain tunnel has obvious space characteristic. The convergence on time axis has lack of regularity,but the accumulated deformation value is small,its harm to tunnel is limited. The surface settlement-time curve and vault settlement-time curve has obvious regularity,the distribution characteristics are closely related to attributes of the surrounding rock and quite different in different sections.