考虑Q3黄土增湿特性的隧道围岩变形分析

力、水耦合作用使黄土结构性降低,开挖扰动和增湿是黄土隧道围岩失稳的主要原因.基于已提出的Q3黄土初始切线模量与含水量的关系,对一典型的黄土隧道进行了增湿变形分析,从围岩的变形、地面沉降、衬砌的受力状态三个方面对比分析了增湿对围岩稳定性的影响.结果表明,含水量从5.175%增大到22%时,隧道拱顶沉降和地面变形均增大了一倍左右,初始含水量较小时,增湿引起较大的围岩变形,初始含水量较大时增湿引起较小的围岩变形;衬砌结构的弯矩和轴力随含水量增大而增大,按规范求得弯矩的设计值大于数值分析的结果,而轴力的设计值小于数值分析的结果.

Analysis on Deformation of Tunnel Surrounding Loess Considering Its Moistening Characteristic

Loess structural properties would be weaken by the couple action of force and water. The main reason that makes tunnel surrounding loess unstable is excavation -disturbance and moistening in loess. In this paper .based on the relationships between initial tangent modulus and water content of loess presented by the authors, an analysis on loess moistening deformation has been carried out. The effects of moistening in loess tunnel have been advanced by means of comparing deformation, ground settlement and stress state of lining. It is shown that the vault crown settlement and ground deformation are doubled when the water content increase from 5. 175% to 22%. The higher initial water content, the less deformation of surrounding loess will be and vice versa. In the process of moistening, the moment and axial force would increase. The moment according to design criterion is bigger than its numerical calculation result and the axial force according to design criterion is smaller than its numerical analysis result.