基于分段线性化模型的一维流变固结分析

One-Dimensional Rheological Consolidation Analysis of Saturated Soft Clay Based on PiecewiseLinear Model

摘要:

为进一步认识饱和软黏土的黏滞效应对其一维固结过程的影响，引入考虑时间效应的统一硬化(UH)本构模型来描述其变形的弹黏塑性，从而改进了一维分段线性化（CS2）固结模型.通过与已有研究成果的对比，证明了UH本构模型以及修正后CS2模型的有效性.在此基础上，探讨UH本构模型参数对固结进程的影响.数值分析表明，饱和软黏土的黏滞效应使得靠近不排水面处的土体在加载初期出现了超孔隙水压力升高的现象，随后减缓了加载中后期地基超孔隙水压力的整体消散，增大了地基的沉降量.同时，随着回弹指数和初始超固结参数的增大，上述流变固结特性更加明显.

关键词:饱和软黏土; 流变固结; 统一硬化本构模型; 分段线性化; 超孔隙水压力; 沉降

Abstract:

To further investigate the influence of the viscous effect of saturated soft clay on its one-dimensional consolidation process, a onedimensional piecewiselinear model, called CS2, was modified by introducing the unifiedhardening (UH) constitutive model considering the time effect to describe the elastic viscoplasticity of soft clay. The validity of the UH constitutive model and the modified CS2 consolidation model was proved by comparing them with existing research results. Then, the effects of the UH constitutive model parameters on the rheological consolidation process were investigated. The numerical results illustrated that the viscous effect of saturated soft clay caused the increase of excess pore water pressure near the undrained surface in the early stage of loading, slowed down the overall dissipation of excess pore water pressure in saturated clay layer, and increased the settlement of ground in the middle and late stage of loading. In addition, the above behaviors of rheological consolidation became more obvious with the increase in the swelling index and initial overconsolidated parameter of soil.

Key words:saturated soft clay; rheological consolidation; unified-harding constitutive model; piecewiselinear; excess pore water pressure; settlement