理想膨胀性非饱和土UH模型  

UH model for ideal expansive unsaturated soils

作　　者：姚仰平[1] 田易川 崔文杰 YAO Yangping;TIAN Yichuan;CUI Wenjie(School of Transportation Science and Engineering,Beihang University,Beijing 100191,China)

机构地区：[1]北京航空航天大学交通科学与工程学院,北京100191

出　　处：《岩土工程学报》2023年第6期1103-1112,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家重点研发计划资助项目(2018YFE0207100);国家自然科学基金项目(51979001)。

摘　　要：膨胀性非饱和土具有吸水膨胀和浸水强度降低的特点,容易引发地基不均匀沉降导致建筑物开裂破坏。构建了与土体干密度和超固结度相关的膨胀式,并将其融入已有的非饱和土UH模型,从而能够合理地描述理想膨胀土湿化过程中体积膨胀与强度降低的特性。与已有模型相比,提出的模型所需参数少,可以更合理地考虑超固结度和初始干密度对膨胀土应力应变关系的影响,同时可以体现膨胀土在超固结状态下的应力软化特性和剪胀特性。该模型在不考虑土体膨胀式时可以退化成已有的非饱和土UH模型。通过与已有膨胀性非饱和土的试验结果对比分析,验证了模型在定量描述膨胀性超固结非饱和土应力应变特性上的合理性。The expansive unsaturated soils are characterised by the behaviour of volume increase and strength reduction during wetting,which may cause nonuniform foundation settlement and further result in cracking of overlaying buildings.A factor accounting for the plastic volumetric expansion is developed,which is associated with the dry density and overconsolidation ratio.This factor is subsequently introduced to the framework of the existing unified hardening(UH)model for the overconsolidated unsaturated soils to properly describe the characteristics of volume expansion and strength reduction during wetting.Compared with other existing models,the model requires fewer parameters,and can adequately account for the influences of the overconsolidation ratio and initial dry density on the stress-strain relationship of the expansive unsaturated soils.Meanwhile,the proposed model can describe the strain-softening behaviour of the expansive soils in the overconsolidated state.This model can be reduced to the existing UH model for the overconsolidated unsaturated soils when the factor accounting for the plastic volumetric expansion becomes zero.The capability of the proposed model in quantitatively describing the stress-strain characteristics of the expansive overconsolidated unsaturated soils is verified by comparing with the existing experimental results.

关 键 词：膨胀性非饱和土 超固结土 弹塑性本构模型 湿化 

分 类 号：TU43[建筑科学—岩土工程]