Q2饱和黄土隧洞围岩变形特征研究  

Study on characteristic of deformation of Q2 saturated loess tunnel′s surrounding rock

作　　者：刘小伟[1,2] 原鹏博[1,2] 谌文武[1,2] 赵红亮[1,2] LIU Xiaowei;YUAN Pengbo;CHEN Wenwu;ZHAO Hongliang(Key Laboratory of Mechanics on Disaster and Environment in Western China,Lanzhou University,Lanzhou 730000,China;College of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]兰州大学西部灾害与环境力学教育部重点实验室,甘肃兰州730000 [2]兰州大学土木工程与力学学院,甘肃兰州730000

出　　处：《冰川冻土》2019年第6期1422-1429,共8页Journal of Glaciology and Geocryology

基　　金：兰州大学中央高校基本科研业务费专项资金项目(lzujbky-2014-3)资助

摘　　要：Q2饱和黄土含水率高,强度低、变形大。饱和黄土隧洞围岩变形破坏一直是工程界关心和亟待解决的问题。利用隧洞围岩收敛变形、二次应力场监控量测与数值分析,获取隧洞围岩动态综合信息,研究在一次支护条件下,隧洞围岩的收敛变形和应力变化特征。结果显示,隧洞围岩收敛变形和应力在最初的10~15天呈线性快速增长趋势。后期,收敛变形随时间呈非线性增加,受一次衬砌的限制,其变形在隧洞开挖30~40天后渐趋于稳定,但应力持续增加,反映Q2饱和黄土隧洞围岩具有显著的时效特性。为避免隧洞围岩压力过大,造成隧洞围岩及支护破坏,建议在开挖后30~40天施作二次衬砌。High moisture content(saturation greater than 85%), low fracture strength and large deformation induce catastrophic problems in the saturated loess tunnels. Surrounding rock dynamic composite information of Q2 saturated loess tunnel was obtained by in-situ surrounding rock deformation and stress measurement. Time effect(rheological property) is the most important factor affecting the mechanical properties of saturated loess tunnel. The convergent deformation and stress of Q2 saturated loess tunnel’s surrounding rock changed rapidly with linear growth trend in the first 10~15 days. Then, the convergent deformation increased nonlinearly and gradually stabilized after 30~40 days after tunnel excavation with the primary lining, but the press increased continuously. Which means that the Q2 saturated loess tunnel’s surrounding rock has remarkable characteristics of rheology. The construction time of secondary lining for saturated loess tunnel is 30~40 days after tunnel excavation.

关 键 词：饱和黄土 围岩变形 二次衬砌 

分 类 号：P642.131[天文地球—工程地质学] U456[天文地球—地质矿产勘探]