中文摘要：

研究目的：为了对上硬下软双层地基土体穿刺深度进行研究，本文采用非线性有限元软件ABAQUS，基于土体弹塑性破坏理论与ABAQUS二次开发技术，比较完善地分析了上部土层穿刺深度的影响因素，并给出了穿刺深度计算公式。研究结论：研究结果表明，穿刺深度与上部土层厚度呈非线性关系，同时受土体弹性模量、非均匀性、基底摩擦等因素的影响；上下土层强度比对上部土层穿刺深度影响较小。

英文摘要：

Research purposes： To study the punch through deepth of two - layered soil foundation with hard over soft, the nonlinear finite element analysis software ABAQUS is adopted. Based on the elastic -plastic failure theory and secondary development of ABAQUS, the influence factors of punch through depth are analyzed in detail, and the formula of punch through depth is achieved. Research conclusions：The results shows that the punch through depth is a founction of thickness of upper layer soil, which can be affected by elastic modulus, nonhomogeneous and friction of footing. The strength ration of soil can affect the ultimate bearing capacity of two - layered soil foundation greatly, but not the punch through depth.