Analysis of long-term settlement of soft clay under train vibration
GE Shiping1,2,3,YAO Xiangjing1,2,3,YE Bin1,2,PU Shutao1,LIU Xuezeng4
(1. Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;3. Shanghai Shentong Metro Group Co.,Ltd.,Shanghai 201102,China;4. Civil Engineering Information Technology Research Center of Ministry of Education,Tongji University,Shanghai 200092,China)
Abstract:The long-term soil settlement was monitored around a tunnel within the range of 1.5 times of the outer diameter of the tunnel of Metro line 9 in Shanghai. A parameter was introduced into an existing dynamic elasto-plastic constitutive model to take into account the effect of long-term cyclic loading. The development of soft clay settlement caused by the train vibration and post-construction consolidation was calculated using the improved constitutive model. The measured settlement of the tunnel invert relative to the ground is 4.7 mm after 850 days of tunnel operation. The calculated settlement is 4.6 mm with the vibration-induced settlement to be 3.1 mm. The difference of measured and calculated settlements is 2%,indicating that the improved constitutive model shows a satisfactory performance on simulating the accumulated deformation characteristics of soft soil under the vibration load. The long-term settlement of the tunnel is in accordance with the exponential growth law with time. In the case of tunnel depth at 13.2 m,the relative settlement of arch bottom tends to be stable after about 8 years,and the relative settlement is 4.2 mm after stability.
SEED H B,CHAN C K. Effect of duration of stress application on soil deformation under repeated loading[C]// Proceedings of the 5th International Congress on Soil Mechanics and Foundations. [S.l.]:[s.n.],1961:341-345.
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