考虑膨胀效应的UH模型及其有限元实现

超固结非饱和土统一硬化(UH)模型在分析超固结非饱和土问题中有广泛的适用性,其不仅可以使超固结状态下的湿化模拟更为合理,也能够反映超固结非饱和土的硬化、软化等特性。在超固结非饱和土本构模型的基础上,考虑土体团粒的吸水膨胀作用,提出了考虑膨胀效应的UH模型。该模型只比超固结非饱和土UH模型增加了一个参数,不仅能够描述普通加载路径下超固结膨润土的应力应变特性,还能反映其在湿化路径下的膨胀效应。基于有限元软件的二次开发平台,进行了考虑膨润土膨胀效应UH模型的有限元实现,并通过对三轴试验和膨胀力试验的数值模拟,验证了模型子程序的合理性。

UH model considering expansion of soils and its finite element implementation

The unified hardening model (UH model) for overconsolidated unsaturated soils is applicable to problems involving unsaturated soils. The wetting behaviors of unsaturated soils in overconsolidated condition can be described more reasonably using this model. It can also describe strain-hardening and softening behaviors of the unsaturated soils better. Based on the UH model for unsaturated soils, a new UH model for bentonite was proposed by considering the expansion of the soil aggregates. With just one more parameter, the proposed model can not only describe the stress-strain behaviors of the bentonite under general loading paths,but also describe the expansion of the bentonite under wetting paths. Based on the secondary development platform of finite element software, the UH model considering the expansion of the bentonite has been implemented. The subroutine was proved to be reasonable through the simulation of the triaxial test and the swelling pressure test using the proposed model.