机械化施工大断面高铁隧道围岩压力测试及分布特征研究

Study of Measurement and Distribution Characteristics of Surrounding Rock Stress of Large Cross-sectional High-speed Railway Tunnel with Mechanized Construction

为了解机械化施工大断面隧道围岩压力的变化规律和分布特征,依托郑万高速铁路湖北段大型机械化施工隧道群,开展大量围岩压力现场监测,根据测试结果对Ⅳ级和Ⅴ级深埋条件下围岩压力变化规律和分布特征进行分析,并与规范荷载进行对比。结果表明:1)围岩压力监测数据从21~27 d开始稳定;2)实测围岩压力小于《铁路隧道设计规范》深埋隧道计算荷载;3)Ⅳ级深埋条件下,侧压力系数为规范荷载侧压力系数的1.2~2.4倍;4)Ⅴ级深埋条件下,侧压力系数为规范侧压力系数的0.86~1.43倍。

A large amount of field measurement on surrounding rock stress of tunnel group on Hubei Section of Zhengzhou-Wanzhou High-speed Railway with mechanized construction are carried out to learn the variation laws and distribution characteristics of surrounding rock stress of large cross-sectional high-speed railway tunnel with mechanized construction.And then the surrounding rock stress variation laws and distribution characteristics of surrounding rock stress in GradeⅣand GradeⅤdeep-buried conditions are analyzed and compared with standard loads based on measurement results.The study results show that:(1)The stabilizing time of surrounding rock stress starts on the 21st to the 27th day.(2)The measured surrounding rock stress is less than the calculated load of deep-buried tunnel in related railway design codes.(3)Under the condition of GradeⅣdepth,the lateral pressure coefficient is 1.2-2.4 times that of standard load.(4)Under the condition of GradeⅤdepth,the lateral pressure coefficient is 0.86-1.43 times that of standard load.