兰渝线两水隧道大变形原因及机理分析

兰渝线两水隧道洞身经过炭质千枚岩、千枚岩等地层，在开挖施工过程中软弱围岩出现了大变形，其变形形式、特征十分复杂。通过对区域地质构造环境，复杂的高地应力及频繁、强烈的地震、围岩结构等方面的综合分析，研究了围岩大变形的机理，以达到控制变形的目的。结果表明:隧道围岩具有松散型、高地应力型及结构变形型的复合特征；大变形是在强烈的地质构造、复杂高地应力的作用下产生的，且与围岩优势结构面、软弱夹层、地下水等因素密切相关。

The Causes and Mechanism Analysis of the Large Deformation of Liangshui Tunnel in Lanzhou-Chongqing Line

Liangshui tunnel of Lanzhou-Chongqing Line passed through carbon-based phyllite and phyllite stratum. During the excavation construction, the weak surrounding rock appeared large deformation with complicated deformation form and features. Through the comprehensive analysis on regional geotectonic environment, complicated high crustal stress and frequent and strong earthquake and surrounding rock structure, etc., the mechanism of large deformation of the surrounding rock is studied so as to control the deformation. The results show that the tunnel surrounding rock has a complex characteristic of relax type, high crustal stress type and structural deformation type. The large deformation is produced under the action of strong geological structure and complex high crustal stress and closely related to the preferred structure plane, weak intercalated layer and the groundwater, etc.