轴对称柱坐标系下固结模型的建立及应用

Formulation and application of a consolidation model in axial symmetric cylindrical coordinates

为模拟井点抽水引起的圆形基坑内外土体位移和地下水位的变化,建立了轴对称柱坐标系下的饱和-非饱和土固结模型,不仅考虑了固结过程中地下水流动引起的饱和度和相对渗透系数的变化以及土骨架变形引起的孔隙率和饱和渗透系数的变化,还考虑了地下结构物的变形特性。基于上述模型,通过模拟圆形基坑抽水-水位恢复试验,研究地下连续墙对水头和土体位移的影响;另外,以上海世博500 k V地下输变电站基坑的抽水试验为例,模拟圆形基坑降水过程,将本模型的数值结果与其他计算结果对比,从而验证模型的准确性和实用性。

A consolidation model for saturated-unsaturated soil is formulated in axially symmetric cylindri-cal coordinates to simulate the land deformations and hydraulic head changes of circular excavations due towell pumping. The changes in saturation and relative hydraulic conductivity caused by underground waterflow and the variations in porosity and saturated hydraulic conductivity due to solid skeleton deformationare considered,so are the mechanical properties of underground structures. Based on this model,a pump-ing-recovery test performed on a circular excavation is simulated to study the effect of diaphragm walls onhydraulic heads and soil displacements. Another pumping test performed on the excavation of 500 k V Shang-hai Expo underground substation is simulated. The numerical solutions are compared with other results,thus the validity and practicability of the model is verified.