考虑空隙压密特征的岩石弹塑性损伤增量本构模型  

Elastoplastic damage incremental constitutive model of rock considering the characteristics of void compaction

作　　者：陈会官 赵程[1,2] 张睿 潘昊宇 CHEN Huiguan;ZHAO Cheng;ZHANG Rui;PAN Haoyu(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩石力学与工程学报》2023年第12期3043-3055,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(U1965108,U22A20597)。

摘　　要：岩石的变形破坏全过程包括压密–弹性–塑性–损伤多个阶段,现有的基于经典弹塑性理论与损伤力学同时考虑岩石压密变形机制的本构模型研究较少。将岩石抽象为岩石骨架与岩石空隙2部分,依据空隙变形机制计算非线性压密变形,基于Drucker-Prager准则分析塑性变形特性,采用体积变形描述损伤演化规律,在经典弹塑性损伤理论框架下建立岩石压密–弹塑性损伤增量型本构模型及其积分算法。将岩石总变形视为压密、弹性与塑性3个部分,考虑空隙部分无法承受剪力且各方向变形无相互影响的特征,通过应力、应变张量谱分解在主应力方向上计算总应变。数值积分方法为基于Drucker-Prager准则的主应力方向回映算法,采用压密弹性预测方法计算预测应力,以分析迭代步中压密应变增量对总应变增量的影响。压密–弹塑性损伤本构模型与算法充分考虑空隙非线性变形机制与压密变形特性,共涉及压密、弹性、塑性、损伤4类10个参数,适用于长期服役过程中外部环境作用下空隙占比逐渐增加,骨架强度逐渐减小的工程岩体。应用模型研究干湿、冻融循环2种典型外部环境对岩石特性的影响,结果表明模型能够很好地模拟外部作用后工程岩体变形破坏的全过程,具有一定的理论意义与工程价值。ed as two parts,the rock skeleton and the rock void.The nonlinear compaction deformation was calculated according to the void deformation mechanism.The plastic deformation characteristics were analyzed using the Drucker-Prager criterion.The damage evolution law was described by the volume deformation.Under the framework of classical elastoplastic damage theory,a compaction-elastoplastic damage incremental constitutive model and its integral algorithm of rock were established.The total deformation of the rock was divided into three parts as compaction,elastic and plastic deformation.The void part cannot bear the shear force and the deformation in each direction has no mutual influence.Therefore,the total strain was calculated in the principal stress direction through the spectral representation of the stress and strain tensors.The numerical integration method was the return mapping algorithm in principal stress space based on Drucker-Prager criterion.The predicted stress was calculated by the compression elastic prediction method.The influence of the compaction strain increment on the total strain increment in one iterative step was analyzed.The compaction-elastoplastic damage constitutive model and algorithm fully consider the non-linear deformation mechanism of voids and compaction deformation characteristics.The proposed model contains ten parameters in four categories including compaction,elasticity,plasticity and damage.It is suitable for engineering rock mass whose void ratio increases and skeleton strength decreases under external action during long-term service.The model was used to study the effect of two typical external environments(dry-wet and freeze-thaw cycles)on rock properties.The results show that the model can well simulate the whole process of rock deformation and failure after external actions,which has certain theoretical significance and engineering value.

关 键 词：岩石力学 压密变形 增量本构模型 DRUCKER-PRAGER准则 主应力回映算法 干湿循环 冻融循环 

分 类 号：TU45[建筑科学—岩土工程]