含瓦斯煤岩耦合弹塑性损伤本构模型研究  

A COUPLED ELASTOPLASTIC DAMAGE MODEL FOR GAS-SATURATED COAL

作　　者：尹光志[1,2] 王登科[1] 

机构地区：[1]重庆大学资源及环境科学学院,重庆400044 [2]重庆大学西南资源开发及环境灾害控制工程教育部重点实验室,重庆400044

出　　处：《岩石力学与工程学报》2009年第5期993-999,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(50874124);国家重点基础研究发展计划(973计划)项目(2005CB221502);国家自然科学基金重点项目(50534080);重庆市自然科学基金计划重点项目(CSTC;2008BA6028)

摘　　要：三维压缩条件下,随着载荷的逐渐增加,岩石类材料内部微裂纹的传播与错动不断加剧,最终导致非线性应力-应变关系、弹性模量的减小、变形的各向异性、体积膨胀以及不可逆塑性变形等结果。这些现象可以利用连续损伤力学及塑性理论来描述。首先为考虑瓦斯吸附对煤岩的影响,在多孔介质有效应力原理中引入瓦斯吸附的膨胀应力,得出适用于含瓦斯煤岩的有效应力计算公式。通过引入与塑性屈服准则相关联的各向异性损伤因子和损伤准则来描述含瓦斯煤岩的塑性变形及损伤演化过程。利用不可逆热力学原理,对含瓦斯煤岩的损伤演化规律及塑性变形与损伤之间的耦合效应进行有效描述。根据实验结果,采用非关联塑性流动法则,建立能反映各种应力条件下力学行为的含瓦斯煤岩耦合弹塑性损伤本构模型。通过理论与实验结果的比较发现,所提出的耦合弹塑性损伤本构模型能真实有效地描述含瓦斯煤岩在不同应力条件下的力学特性;同时,该模型还适用于其他岩石类材料的本构描述。Under triaxial compressive conditions, with an increase of loading, the propagation and sliding of microcracks in rocklike materials become increasingly intense and lead to a serial of consequences, such as nonlinear stress-strain relationships, deterioration of elastic modulus, anisotropic deformation, volumetric dilatancy and irreversible plastic strain, etc.. These phenomena may be described by continuum damage mechanics and plastic theory. Firstly, in order to take into account the effect of gas adsorption, the swell stress of gas adsorption is introduced into the effective stress principle of porous media; and the effective stress formulation for gas-saturated coal is derived. Anisotropic damage with plasticity yield criterion and damage criterion are introduced to be able to adequately describe the plastic and damage behavior of gas-saturated coal. Damage evolution law and the coupling between plastic deformation and damage are represented using the framework of irreversible thermodynamics. On the basis of the experimental results, a general coupled elastoplastic damage constitutive model is developed for the mechanical responses of gas-saturated coal under various loading conditions by adopting a non-associated plastic flow rule. The comparison between experimental dada and their simulation equivalents is performed for gas-saturated coal under various stress states. It is obvious that the proposed model is able to effectively depict the main features of mechanical behavior observed in gas-saturated coal. At the same time, the proposed model is also suitable for constitutive description of other rocklike materials.

关 键 词：数值分析 弹塑性 各向异性损伤 本构模型 多孔介质 含瓦斯煤岩 

分 类 号：O241[理学—计算数学]