复杂应力状态下岩土材料非线性本构模型研究

基于统一强度理论,将洛德参数引入统一强度理论,推导出材料的统一强度参数,进而分析中间主应力以及主剪应力系数对材料统一强度参数的影响。在此基础上,对邓肯张双曲线模型进行改进,使得该模型能够反映复杂应力状态下的应力应变关系。采用粘土的平面应变试验进行验证,结果表明:在平面应变情况下,当b=0.4时,模型能够较好地反映粘土的应力应变关系,及其强度参数。分析了洛德参数以及中间主应力系数对模型的影响,进一步说明岩土材料存在主应力效应。该模型能够反映不同材料在复杂应力状态下的应力应变关系,有其更为广泛的适用性。

Non-linear Constitutive Model for Geomaterials under Complicated Stress State

Based on unified strength theory,Lode parameter is introduced,and unified strength parameters of material are obtained then Duncan-Chang model is revised to reflect stress-strain relationship under complicated stress state.The improved model is verified by plane strain test of clay,and results show that the model can predict stress-strain relationship and strength parameters under plane strain test for failure criterion parameter b=0.4.The effects of Lode parameter and the intermediate principal stress on the model are also analyzed.The revised model enables to predict stress strain relationship of different material under complicated stress state to widen the engineering applications.