摘要
根据深部岩体在卸荷条件下能量释放、消耗和转移的过程中,其体积变形经历弹性回弹和扩容以及剪切变形可能经历峰值前(弹性和内摩擦强化阶段)和峰值后(软化及残余破坏阶段)阶段的性状,提出深部岩体变形破坏全过程动态本构模型。该模型的特点可归纳为:(1)引入Juamann导数,能够计算有限变形;(2)描述卸荷过程中与时间相关的体变回弹、扩容至破裂的全过程关系;(3)描述了卸荷过程中,深部岩体强度(长期强度、破坏强度和残余强度)被调动的演化过程,并用同轴的屈服面、破坏面与残余破坏面3个圆锥面加以描述;(4)运用物理细观力学理论,引入宏观裂纹扩展滞后时间表征岩体不同构造水平在强化中的贡献,给出内摩擦强化阶段流变方程;(5)运用裂纹运动散布理论,引入破裂时间表征宏观裂纹扩展贯通过程,给出破裂过程中的强度随时间的演化方程,用塑性流动理论给出软化阶段形变本构方程。最后,在LS-DYNA平台下对本构模型进行二次开发,通过深埋地下隧洞开挖变形破坏的算例,初步展示该模型在深部岩体力学理论与工程中的应用前景。
The unloading of deep rock mass means energy redistribution.In the processes of energy release,dissipation and transfer,the volumetric deformation experiences elastic resilience and volumetric dilatation,and the shear deformation may experience pre-peak（elastic and internal frictional hardening stages） and post-peak（softening and residual failure stages） stages.In order to describe these characteristics,a new dynamic constitutive model to describe the whole deformation process is presented.The characteristics of this model can be summarized as follows：（1） Juamann derivative is employed to compute large deformations.（2） The elastic resilience and volumetric dilation with time are considered to establish the volumetric deformation constitutive relationship.（3） The enforcing process of strength and three coaxial conical surfaces（yield surface,peak strength surface and residual strength surface） are used to describe this evolution process.（4） According to physical mesomechanics,the lag time of fracturing which can present the contribution of different structural levels is employed to establish the rheological equation for hardening stages.（5） According to crack propagation theory,fracturing time to present the propagation and evolution of macrocracks is employed to establish the equation of strength evolution.Finally,deformation constitutive equation is given using theory of plastic flow.Secondary development of the model is operated in ABAQUS platform.With case studies of deformation and failure patterns of rocks excavation in deep tunnel,the prospective of this model to describe the mechanical behaviors of deep rock mass and its engineering applications are shown.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2013年第6期1112-1120,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
国家重点基础研究发展计划(973)项目(2010CB732003
2013CB036005)
国家自然科学创新研究群体科学基金项目(51021001)
关键词
岩石力学
深部岩体
本构模型
峰后
扩容
rock mechanics
deep rock mass
constitutive model
post peak
volume expansion
