列车振动荷载作用下隧道周边软黏土长期沉降分析

发布时间：2018-01-13 10:32

本文关键词：列车振动荷载作用下隧道周边软黏土长期沉降分析　出处：《岩石力学与工程学报》2016年11期 　论文类型：期刊论文

【摘要】：以上海地铁9号线三期工程为背景,对隧道周边1.5倍隧道外径范围内土体长期沉降进行现场监测。为分析上海软黏土在列车长期循环动荷载下的变形特征,通过引进考虑长期循环荷载作用效应的控制参数对现有动力循环加载弹塑性本构模型进行改进;采用改进的本构模型分析列车振动、工后固结2种工况下软黏土沉降发展规律。结果表明:通车850 d后,隧道拱底相对于地面的沉降实测值为4.7 mm,计算值为4.6 mm,其中由列车振动引起的沉降为3.1 mm,误差为2.0%,表明改进后的本构模型能够较好地模拟软黏土在列车振动荷载下的累积变形特征;振动荷载下隧道长期沉降符合指数型增长规律;在隧道埋深13.2 m情况下,列车振动引起的隧道拱底相对于地面的沉降经过约8 a趋于稳定,稳定后相对沉降量为4.2 mm。
[Abstract]:Based on the third phase project of Shanghai Metro Line 9, the long-term settlement of soil in the range of 1.5 times of tunnel diameter around the tunnel was monitored on the spot. The deformation characteristics of soft clay in Shanghai under the long-term cyclic dynamic load of the train were analyzed. The existing dynamic cyclic loading elastoplastic constitutive model is improved by introducing control parameters which take into account the effect of long-term cyclic load. The improved constitutive model is used to analyze the train vibration and the settlement and development of soft clay under the two conditions of post-construction consolidation. The results show that after being opened to traffic for 850 days. The measured settlement of the arch bottom of the tunnel is 4. 7 mm and the calculated value is 4. 6 mm. The settlement caused by the train vibration is 3. 1 mm and the error is 2.0%. It is shown that the improved constitutive model can well simulate the cumulative deformation characteristics of soft clay under train vibration load. The long-term settlement of the tunnel under vibration load accords with the exponential growth law. Under the condition of 13.2 m buried depth of tunnel, the settlement of tunnel arch bottom caused by train vibration relative to the ground tends to be stable after 8 years, and the relative settlement is 4.2 mm after stabilization.
【作者单位】：同济大学地下建筑与工程系;同济大学岩土及地下工程教育部重点实验室;上海申通地铁集团有限公司;同济大学土木信息技术教育部工程研究中心;
【基金】：国家重点基础研究发展计划(973)项目(2015CB057806) 国家自然科学基金资助项目(51278377)~~
【分类号】：U452.11
【正文快照】： 上海地铁70%以上隧道处于淤泥质黏土中,其具有含水量高、孔隙比大、抗剪强度低、压缩性高等特性。随着隧道施工过程中产生的超孔隙水压力不断消散,土体产生工后沉降,加之列车运营期间连续不断的列车循环荷载,使得运营期间软基沉降在机制以及发展特征上复杂化,具有动、静双方面

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