宝兰客专泥岩隧道受力特性试验研究

摘要

Based on the engineering background of Anding mudstone tunnel on Baoji-Lanzhou Passenger Dedi-cated Lines,the physical properties of mudstone and the change over time and the distribution law of the parame-ters such as surrounding rock pressure,stress in steel arch,stress between the first linings and the second lin-ings,steel axis force in the secondary lining,concrete stress,etc were studied through comprehensive on-site monitoring and geotechnical tests.The results show that the swelling property of mudstone ranges from no swelling to weak swelling,but there is a certain disintegration of mudstone with presence of water.The surrounding rock stress grows over time,the surrounding rock pressure of inverted arch is the maximum,which all tends to be sta-ble in the end.The value of stress in steel arch is not stable,even with large fluctuation.The stress in steel arch of side wall foundation is also the maximum,however,it tends to be stable in the end.The stress between first linings and second linings is larger overall with large fluctuation,and the stress of side wall foundation is the maximum,increases over time and finally tends to be stable.The steel axis force in the secondary lining is com-pressive,the value in steel axis force of both inside and outside is approximate.Concrete stress is relatively gen-erally large,where the stress in right arch springing appear to be tensile stress,and the stress in left arch spring-ing are larger than those in the right side.%以宝兰客专上的安定泥岩隧道为工程背景，通过现场监测并结合室内相关土工试验，研究泥岩物理特性、围岩压力、钢拱架应力、初支与二衬接触压力、二衬钢筋轴力和混凝土应力等参数随时间变化的规律及空间分布特征。研究结果表明：安定隧道泥岩的膨胀性为无膨胀至弱膨胀，但泥岩遇水存在一定的崩解性。各测点围岩压力随时间增长，仰拱拱底的围岩压力最大，但最后都逐渐趋于稳定；钢拱架应力值不稳定，分布不均，波动较大，边墙墙脚处应力最大，但最终趋于稳定；初支与二衬接触压力总体较大，变化幅度较大，在边墙墙脚和拱顶处应力最大且随着时间增加最后趋于稳定值；二衬钢筋轴力均表现为压应力，内外层钢筋轴力变化趋势近似；混凝土应力普遍偏大，右拱脚处出现拉应力，左侧应力大于右侧应力。