Abstract The tunnel project in saturated soft loess is characterized by unfavorable engineering behavior and high construction risk. Taking the mined tunnel of Xi′an metro line 5 as the background, the main construction technical measures and effects of the mined tunnel under large-thickness saturated soft loess stratum are studied based on the site construction process, monitoring data and several groups of finite element numerical simulation. The research result shows that: unwatering is easy to realize in the saturated soft loess and its engineering behaviors are good after dewatering, so dewatering is an important means to treat saturated soft loess; the settlement caused by dewatering in saturated soft loess layer is large while the settlement in the area beyond the dewatering affected area is mainly integral and uniform, and the differential subsidence is small; dewatering or a combination of dewatering and grouting should be given the priority as for the tunnel closely adjacent to the important building. Isolation pile can be adopted to effectively protect the adjacent building when it′ s necessary; the grouting effect in saturated soft loess stratum is poor in condition of no dewatering, so more specific and appropriate grouting technology and grouts need to be studied.
Abstract：
The tunnel project in saturated soft loess is characterized by unfavorable engineering behavior and high construction risk. Taking the mined tunnel of Xi′an metro line 5 as the background, the main construction technical measures and effects of the mined tunnel under large-thickness saturated soft loess stratum are studied based on the site construction process, monitoring data and several groups of finite element numerical simulation. The research result shows that: unwatering is easy to realize in the saturated soft loess and its engineering behaviors are good after dewatering, so dewatering is an important means to treat saturated soft loess; the settlement caused by dewatering in saturated soft loess layer is large while the settlement in the area beyond the dewatering affected area is mainly integral and uniform, and the differential subsidence is small; dewatering or a combination of dewatering and grouting should be given the priority as for the tunnel closely adjacent to the important building. Isolation pile can be adopted to effectively protect the adjacent building when it′ s necessary; the grouting effect in saturated soft loess stratum is poor in condition of no dewatering, so more specific and appropriate grouting technology and grouts need to be studied.
CAO Ping LI Jiwei LU Zhiqiang LIU Jianwei
.Study on Construction Technology of Mined Metro Tunnel in Large-thickness Saturated Soft Loess Stratum[J] MODERN TUNNELLING TECHNOLOGY, 2020,V57(6): 177-185
2020, Vol. 57 