不排水条件下黏土本构关系的数值建模

Numerical modelling of constitutive relations for clay under undrained stress path

采用数值建模方法建立了不排水条件下黏土的弹塑性本构模型,为不排水条件下土体工程的计算机仿真提供了符合实际的本构方程.通过可视化给出整个应力场中排水与不排水条件下剪应变的三维变形曲面,对比两者发现,无论应力范围还是曲面坡度都存在显著差异;排水与不排水条件下的剪切屈服轨迹基本变化趋势相差不大,但不排水条件下剪应变上升较快;排水条件下的体积屈服轨迹开始稍微向右偏转,然后缓慢地向左偏转,而不排水条件下体积屈服轨迹开始也稍微向右偏转,然后较快地向左偏转.

The elasto-plastic constitutive model for clay under undrained stress path has been developed by using the method of numerical modelling, which provides a practicable constitutive equation for computer simulation of geotechnical engineering under undrained condition. The three-dimensional surfaces of shear strain under drained and undrained conditions in the whole stress field are presented through visualization, it is found that there are obvious differences in stress ranges and slope between the two ones. In addition, it has been found by respectively comparing the two families of shear and volumetric yield loci for drained and undrained conditions that the differences in basic trends of variation between the two families of shear yield loci are small, but the shear strains of undrained rise rapidly, and the volumetric yield loci for drained firstly turn right slightly, then turn left slowly, however those for drained also firstly turn right slightly, but then turn left fast.