车振荷载引起的软土越江隧道长期沉降分析

随着越江隧道建设的高速发展,车振荷载引起的隧道长期沉降已成为亟待解决的问题。针对一些由于交通车辆运行引起的饱和软土地基长期沉降问题,比较实用的预测方法是基于循环累积变形的经验拟合公式。考虑到土体的真实K0固结应力状态对土体强度和变形的影响,对笔者以前提出的经验拟合公式进行了改进,建立了K0固结条件下软黏土的不排水累积应变与累积孔压实用计算公式;并对上海地区典型饱和软土所进行的非等向固结不排水循环三轴试验结果进行了经验拟合,得到了相关参数。同时结合工程实用的分层总和法,建立了长期沉降的简化计算方法,最后对某越江隧道工程的长期沉降进行预测。更多还原 AbstractFilter('ChDivSummary','ChDivSummaryMore','ChDivSummaryReset');

Long-term settlement of tunnels across a river induced by vehicle operation

With rapid development of river tunnel engineering,long-term settlement of soft ground induced by traffic operations has caused high concerns.For the propose of analyzing long-term settlement of saturated soft clay ground under traffic loading,simplified methods based on semi-empirical models for predicting the accumulative deformations of soft clays are usually preferred.A new empirical model is proposed in order to simulate cumulative plastic strain and pore pressure of anisotropically consolidated soft clays based on undrained cyclic triaxial tests,which extends a semi-empirical formulation previously presented by the authors for isotropically consolidated clays.Unlike the previous model,a new formulation is introduced to take effects of initial K0-consolidated stress state into consideration.Parameters of the empirical model are determined based on undrained cyclic triaxial tests on anisotropically consolidated Shanghai soft clay.Based on the layer-wise summation method,a simplified method is suggested to calculate the long-term settlement of soft ground caused by traffic loading.Analysis for settlement of a typical river tunnel project is presented to demonstrate the new method