宝兰客专魏家嘴黄土隧道受力特性试验研究

摘要

Based on the engineering background of Weijiazui loess tunnel on Baoji -Lanzhou Passenger Dedicated Lines (PDL),the changing law with time and distribution feature of surrounding rock pressure,stress in steel arch,stress between the first linings and the second linings,steel axis force in the secondary lining,concrete strain are studied.The safe status of actual engineering was assessed by virtue of exisiting reliability theory.The results show that surrounding rock stress increases over time and increases faster,the surrounding rock pressure of vault is minimal,the surrounding rock pressure of the bottom of the arch is the largest,tends to be stable in the end;The value of stress in steel arch is not stable,and the fluctuation is larger,but tends to be stable in the end;Stress between the first linings and the second linings is smaller overall,the change is small,and increases over time and finally tends to stabilized value;Steel axis force in the secondary lining is given priority to with pressure,the inside of the steel axial force value change more unstable,but tends to be stable in the end;Con-crete strain is relatively stable,the value is generally smaller,but the stress of the bottom of the arch increases with increasing time and finally tend to be larger strain value.%以宝兰客运专线上的魏家嘴隧道为工程背景，通过现场监测，研究围岩压力、钢拱架应力、初支与二衬接触压力、二衬钢筋轴力、混凝土应变等参数随时间变化的规律及分布特征，并应用现有可靠度理论和数据对实际工程安全状态进行评估。研究结果表明：围岩压力随时间增长而且增长速度较快，拱顶围岩压力最小，仰拱拱底的围岩应力最大，最后都趋于稳定；钢拱架应力值不稳定，波动较大，但最终趋于稳定；初支与二衬接触压力总体偏小，变化幅度较小，且随着时间增加最后趋于稳定值；二衬钢筋轴力以压力为主，内侧钢筋轴力值变化比较大不稳定，但最后趋于稳定；混凝土应变比较稳定，值普遍较小，但仰拱拱底应变随时间的增加而逐渐增大最后趋于较大应变值。