The Liangshui Tunnel on Lanzhou-Chongqin Railway is a single-tube double-track tunnel with the total length of 5945. 35 meters, passing through the stratum of silurian carbonaceous phyllite, accompanied by high ground stresses. In the process of construction for it, the large deformation once occurred, and the initial supporting had to be replaced over and over again due to intruding into the clearance limitation. So the safety risk of the project was relatively high and it was difficult to construct this project. In this thesis, the characteristics of the soft rock tunnel with high ground stress as well as the features of large deformation were researched, and then the bench length of three-bench seven-step excavation method which has influence on the deformation was analyzed contrastively. The results of contrastive analysis showed that the micro bench method was more conductive to control the deformation. Simultaneously, a series of auxiliary technical measures were also adopted for controlling the deformation,and eventually the large deformation of the tunnel was controlled effectively. This case can serve as a helpful reference for the construction of soft rock tunnel with high ground stress.%兰渝铁路两水隧道全长5945．35 m,设计为单洞双线隧道,洞身穿过志留系炭质千枚岩地层,属于高地应力,施工中出现大变形、初期支护侵限多次拆换,安全风险高,施工难度极大。通过分析高地应力软岩隧道特点和大变形特征,对三台阶七步开挖法的台阶长度对变形影响进行了对比分析,认为采用微台阶法更有利于控制变形,同时配合系列变形控制技术措施,有效地控制了隧道大变形,对高地应力软岩隧道施工进行了有益的探索。and eventually the large deformation of the tunnel was controlled effectively. This case can serve as a helpful reference for the construction of soft rock tunnel with high ground stress.
展开▼
