交通荷载作用下低路堤软粘土地基累积沉降规律分析

Traffic-load-induced Cumulative Settlement of Soft Clay Subgrade of Low Road Embankment

基于黄茂松提出的上海软粘土不排水累积变形模型和累积孔压模型,借助静态和动态有限差分法,对上海软粘土地基的累积沉降进行了计算分析。结果表明:累积沉降包含不排水累积变形和累积孔压消散引起的变形2个部分,但前者是主要的;累积沉降随时间先急剧增大,然后逐渐变缓;当路堤高度小于1.5 m时,随着路堤高度的减小,地基累积沉降增加很快;车载越大,累积沉降增大速度越快,超载0.2倍,累积沉降将增大44%,因此限制超载是减小累积沉降的关键;提出的软粘土地基累积沉降预测公式能很好地反映路堤高度和车载的影响。

Based on the undrained cumulative deformation model and the cumulative pore pressure model of the soft clay presented by Huang and employing the static and dynamic finite difference method, the cumulative settlement of Shanghai soft clay subgrade was computed and analyzed. Results show that the cumulative settlement consists of the undrained cumulative deformation and the deformation due to the dissipation of cumulative pore pressure, however, the former is principal. The cumulative settlement increases sharply with time in initial open stages of traffic and then gradually tends to stable state. When the road embankment is less than 1.5 m height, the cumulative settlement increases rapidly with the decrease of the road embankment height. The more vehicle load is, the more sharply cumulative settlement increases. When the overload ratio is 0.2, the increase ratio of the cumulative settlement is 44% So overload limiting is critical to control the cumulative settlement. The presented formulas of the cumulative settlement prediction can well reflect the effects of road embankment height and vehicle loads.