有关砂土地基承载力数值解析问题的讨论

以砂土地基的极限承载力为对象,讨论了古典理论解与室内模型实验值之间的差异,并结合试验中所观察到的现象对其原因进行了简要的分析,最后,利用有限元解析对各种极限承载力的计算方法进行了客观地评价。砂土材料强度具有明显的各向异性以及软化特性,并与周围压力大小以及密度相关。另外,砂土地基的破坏呈渐进性,砂土的粒径大小影响它的承载力以及变形破坏。结果表明,只有考虑砂土以上的各种特性的数值解析方法才能合理地得到砂土地基的极限承载力。

A work-hardening and softening constitutive model for sand:modified plastic strain energy approach

The paper describes an energy-based constitutive model for sand, which is modified based on the modified plastic strain energy approach, represented by a unique relationship between the modified plastic strain energy and a stress parameter, independent of stress history. The modified plastic strain energy approach was developed based on results from a series of drained plastic strain compression tests along various stress paths on saturated dense Toyoura sand with accurate stress and strain measurements. The proposed model is coupled with an isotropically work-hardening and softening, non-associtated, elasto-plastic material description. The constitutive model concerns the inherent and stress system-induced cross-anisotropic elastic deformation properties of sand. It is capable of simulating the deformation characteristics of stress history and stress path, the effects of pressure level, anisotropic strength and void ratio, and the strain localization.