基于改进西原模型的软土流变一维固结解析

为解决不同应力水平下饱和软土层的沉降计算问题,考虑土的流变特性,对西原模型低应力分量进行了分析和改进.通过Laplace变换与反变换,得到了瞬时加载条件下改进西原模型的一维固结解析解,在此基础上采用积分的方法推导了多级加载条件下的统一解析解,并将解析解应用于洞庭湖软土路堤试验段的沉降计算.结果表明:该解析解沉降计算值在不同应力水平下呈现不同的变化规律,均与对应应力水平下的沉降实测值吻合.在固结初期,该解析解的计算固结沉降速率大大低于相同条件下弹性模型的计算结果.因此,在计算软基沉降时,必须考虑不同应力水平对软基沉降的影响,并考虑软土流变所引起的滞后效应.

Analytical Solution for Rheological One-dimensional Consolidation of Soft Soil based on Improved Nishihara Model

In order to solve the settlement calculation problem of saturated soft soil under different stress levels, the low stress component of the Nishihara model was analyzed and improved after considering the rheological properties. Through the Laplace transform and its inverse transform, a one-dimensional consolidation analytical solution was obtained under instantaneous loading condition. Based on the solution, the unified analytical solution was obtained in the method of integral under multilevel loading conditions. And the analytical solution was used in the settlement calculation for the test section of Dongting Lake Area soft soil embankment. It has been shown that the calculated settlement values of the analytical solutions under different stress levels have different change laws, which is in agreement with those of the field tests. At the early stage of consolidation, the calculated consolidation settlement rates are much lower than that of the elastic model under the same conditions. Therefore, when calculating the settlement of soft foundation, it is necessary to consider the influence of different stress levels on the settlement of soft foundation, and to consider lag effect caused by soft soil creep.