饱和土体柱形扩孔时大变形不排水统一解析解

 将柱孔周围的土体分为弹性区和塑性区，在弹性区中采用小变形理论，在塑性区中采用大变形理论和统一强度准则。根据应力平衡方程、应力和应变连续的边界条件，推导出考虑土体大变形和不排水时柱形扩孔问题的塑性区半径、极限扩孔压力和超孔隙水压力的理论解答。理论计算结果与现场实测结果较为接近，说明该理论具有一定的参考价值。通过计算分析还可知：扩孔压力随着参数b的增大而非线性增大，而超孔隙水压力则正好相反。

UNIFIED ANALYTICAL SOLUTIONS FOR CYLINDRICAL CAVITY EXPANSION IN SATURATED SOIL UNDER LARGE DEFORMATION AND UNDRAINED CONDITIONS

The strain distribution around the cylindrical cavity is classified into plastic zone and elastic zone. The theories of small deformation and large deformation are adopted in the elastic zone and plastic zone respectively. According to the stress equilibrium equation and conditions of stress and strain，the stress distribution in two zones，radius of the plastic，limited cavity expansion pressure and excess pore pressure are obtained considering large deformation and undrained conditions. The results agree well with those of the in-situ test，which proves that the proposed theory has certain reference value. The calculations show that with the increase of parameter b，the limited cavity expansion pressure increases nonlinearly while the excess pore water pressure is on the contrary.