雅鲁藏布江峡谷段某深埋隧道岩爆特征分析

Rock Burst Problems in the Tunnel of Yarlung Zangbo River Section of Lasa to Rikaze Railway

拉萨至日喀则铁路以隧道形式穿越雅鲁藏布江峡谷段。受区域地质环境的影响,区段内盆因拉围岩内构造应力集中,施工过程中岩爆问题突出。在对现场地应力数据和隧道围岩物理力学特性参数的实验测试的基础上,分析了盆因拉深埋隧道花岗岩、片麻岩和闪长岩围岩体的弹性应变能、强度和变形脆性系数以及弹性应变能等指标,进而分析了围岩体岩爆倾向。利用MIDAS有限元软件计算了隧道洞壁最大切向应力,应用Russeness和Barton判据对围岩岩爆强度进行了评判。其中花岗岩具有轻微—中等岩爆倾向;片麻岩具有中—强岩爆倾向,局部具有轻微岩爆倾向;闪长岩具有强岩爆倾向,局部具有轻微—中等岩爆倾向。计算结果和施工监测结果一致,研究结论为该区域类似工程施工提供了参考。

The Lasa to Rikaze railway run across yarlung zangbo river by tunnels. The geologic environment causes high ground stress on surrounding rock in the tunnel. The rock burst became the main problem during the construction. Based on the field investigation,in-situ stress test and the laboratory rock physical and mechanical tests,the indices for the tendency for rock burst of granite,gneiss and diorite rock mass in the tunnel,such as the elastic energy of deformation index,the rock brittle coefficient of strength,the rock brittle coefficient of deformation and the biggest storage elastic strain energy were analyzed. The maximum tunnel wall stress was calculated by using the finite element method（ MIDAS） then the Russeness and Barton criterions were adopted to predicate the rock burst.The results are as follows： the granite is mainly the weak-medium rock burst proneness; gneiss is mainly the medium-intense rock burst proneness,and some sections of weak rock burst proneness; diorite is mainly the intense rock burst proneness,some sections of weak-medium rock burst proneness.