隧道开挖下黏土地层作用分区
Action zoning in clay stratum caused by tunnel excavation
-
摘要: 针对北京地区典型粉质黏土地层隧道开挖问题,进行了多组三轴固结排水试验,分析了不同类型应力路径下土样的力学特性,并建立隧道开挖二维数值模型.选取一般工程材料参数,计算每步开挖下网格点及高斯点的应力,跟踪记录典型样点的应力变化规律,进而将地层划分为不同作用分区,将强度试验结果依次代入对应模型分区后得出考虑分区的地表最终沉降值.最后构建离心机试验模型,记录稳定后的表面沉降值,对比了分区模拟计算结果,验证了隧道开挖下地层作用分区的正确性.Abstract: Aiming at analyzing the tunnel excavation problem in representative silty clay stratum in Beijing,triaxial consolidation drainage tests were carried and the mechanical characters under different stress paths were analyzed.Then,a two-dimensional numerical tunneling model with general engineering parameters was established.The stress of grid points and Gauss points was calculated,and the stress changes of typical points were tracked.After that,the action zones of the stratum were classified,and the final ground settlements which consider action zones were calculated by turning the test results of strength into the corresponding action zone model.At last,a centrifuge test model was constructed,and the final surface settlement value was recorded.By contrasting test results with simulation results,the correctness of action zoning in silty clay stratum was verified.