三维激光扫描辅助隧道大变形控制研究

3D Laser Scanning Assisted Tunnel Large Deformation Control

为解决在高地应力软岩大变形隧道控制研究中,传统监测方法有限断面有限点、监测结果以点带面、难以发现最大最小平均变形,无法为隧道初支优化调整提供有效数据支撑等问题,以沙嫰山二号隧道为依托,采用三维激光扫描仪对隧道初期支护进行全息变形监测,获取隧道初期支护的变形全貌,并进行沉降收敛和断面轮廓变形分析。同时依据三维激光变形监测结果,设计适应隧道变形特征的限阻耗能支护结构,对软岩大变形隧道初期支护破坏问题进行控制。结果表明:(1)三维激光扫描仪与全站仪沉降监测方差为3.03 mm、收敛监测方差为3.42 mm,两种仪器监测精度相当;(2)三维激光扫描仪监测结果显示,初期支护左侧出现受围岩剪切滑移带影响的局部鼓出问题,鼓出影响范围为左拱脚至左拱腰,且沿里程方向呈现明显的时空效应,监测段初期支护变形包络结果显示,拱顶左侧变形平均值35.2 cm、右侧变形平均值16.4 cm;(3)依据三维激光扫描仪监测结果不对称的设计限阻耗能支护结构,与设计支护段相比,对初期支护破坏取得了较好的控制效果,同时通过变形加速度来判断隧道变形速率的发展,避免累计变形和变形速率预警中假型性预警现象。

In order to solve the problem that in the study of high ground stress soft rock large deformation tunnel control,the traditional monitoring methods have limited sections and points,the monitoring results are point by point,and it is difficult to find the maximum and minimum average deformation,which cannot provide effective data support for the optimization of tunnel initial support adjustment.Based on Shanenshan tunnel No.2,a 3D laser scanner is used to monitor the holographic deformation of the tunnel initial support,to obtain a full picture of the deformation of the tunnel initial support,and to analyze the settlement convergence and section profile deformation.Meanwhile,based on the 3D laser deformation monitoring results,we design the SRLD support structure to adapt to the deformation characteristics of the tunnel,and control the damage of the initial support of soft rock large deformation tunnel.The results show that:(1)the variance of settlement monitoring between 3D laser scanner and total station is 3.03 mm,and the variance of convergence monitoring is 3.42 mm,the monitoring accuracy of the two instruments is approximate.(2)the monitoring results of 3D laser scanner show that the left side of the initial support appears to be affected by the shear-slip zone of the surrounding rock with local bulging problem,the bulging influence range is from the left arch foot to the left arch waist,and along the mileage direction shows obvious spatial and temporal effect.(3)based on the 3D laser scanner monitoring results,the asymmetric design of the energy-limited support structure,compared with the design support section,has achieved a better control effect on the initial support damage,while the development of the tunnel deformation rate is judged by the deformation acceleration,which can avoid the phenomenon of false type of warning in the cumulative deformation and deformation rate warning.