小应变土体硬化模型参数的敏感性分析及确定方法

小应变土体硬化(Hardening soil model with small strain stiffness, HSS)模型能够反映土体小应变阶段的非线性特性和应力相关性,在深基坑工程领域已被广泛应用,但由于参数众多,目前对参数确定方法尚缺乏系统研究。分析了HSS模型各参数的意义及常规确定方法,采用数值模拟方法开展了HSS模型参数的敏感性分析,基于统计的大量研究成果,建立了土体参数与孔隙比之间的非线性关系,进一步通过2处深基坑工程的变形分析进行验证。结果表明：在基坑数值分析中,参考动剪切模量 的敏感性最高,参考切线模量 的敏感性最低,建立的非线性关系能够较好的反映土体模量与孔隙比的相关性,围护结构侧移的计算值及实测值较为吻合,验证了提出的参数确定方法的适用性,可为相关工程提供参考。

Sensitivity analysis and determination method research of parameters for hardening soil model with small strain stiffness

Hardening soil model with small strain stiffness (HSS model) can reflect the nonlinear characteristics and stress correlation of the small strain phase of soil, which has been widely used in deep foundation pit, but there is a lack of systematic research on the parameter determination methods owing to the numerous parameters. Sensitivity analysis of HSS model parameters was carried out by numerical simulation method. Based on a large number of statistical research results, the nonlinear relationship between soil parameters and void ratio was established and verified by deformation analysis in two deep foundation pit projects. The results showed that the sensitivity of the reference dynamic shear modulus was the highest and the sensitivity of the reference tangent modulus was the lowest in the numerical analysis of the foundation pit, the established nonlinear relationship could better reflect the correlation between the soil modulus and the void ratio, and there was a good agreement between the calculated and measured values of the enclosure lateral displacement, which verified the applicability of the proposed parameter determination method and could provide reference for related projects.