A structural constitutive model of undisturbed saturated clays based on#br#
the uniform hardening parameter
WAN Zheng1，2，3，QIU Rendong1，2，3，SONG Chenchen4
(1. Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering，Guilin University of Technology，Guilin，Guangxi 541004，China；2. Research Institute of Base and Foundation，China Academy of Building Research，Beijing 100013，China；
3. Beijing Foundation and Underground Space Utilization Engineering Technology Research Center，Beijing 100013，China；
4. Department of Disaster Mitigation for Structure，Tongji University，Shanghai 200092，China)
Abstract：Based on the characteristics of saturated structural clays and the uniform hardening(UH)parameter，the UH model was modified to reflect the stress-strain relationship of the structural clay. The improved model has the following features：(1) the yield surface being shifted to the left in the p-q coordinate system can reflect certain tensile strength characteristics and，because of that the left end of the yield surface is located to the left of the origin point，the loss law of the cementation strength caused by the development of the volume strain can be described by a proposed evolution equation of left movement of the yield surface，(2) by introducing the state parameter χ to describe the variation of the strength of the phase transformation stress ratio corresponding to the moment when the volume strain changes from shrinkage to dilatation，the volume strain amount and the transformation rule can be determined according with different cementation degrees，and (3) for the characteristics of large volume shear contraction of structural clays under loading，a structural stress ratio parameter R* and a formula of the structural potential strength based on R* were proposed. By using the potential strength to revise UH parameter，a simple model for describing the stress-strain relationship of structural clays was obtained，which reflects the following characteristics including the high stress ratio strength，gradual decrease of the cementation strength along with the volume contraction，large volume shear shrinkage，strain softening accompanied by cementation loss，shear shrinkage and dilatancy.
万 征1，2，3，秋仁东1，2，3，宋琛琛4. 基于统一硬化参量的原状饱和黏土的结构性本构模型[J]. 岩石力学与工程学报, 2019, 38(9): 1905-1918.
WAN Zheng1，2，3，QIU Rendong1，2，3，SONG Chenchen4. A structural constitutive model of undisturbed saturated clays based on#br#
the uniform hardening parameter. , 2019, 38(9): 1905-1918.
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2019, Vol. 38 
