单轴压缩下断续节理岩体动态损伤本构模型

断续节理将对工程岩体的强度及变形等力学特性产生显著影响，损伤力学中视节理为岩体的一种宏观损伤，因而采用损伤张量来刻画其对岩体的影响。目前学术界提出了用节理的几何、强度及变形等3类参数来描述节理的物理力学性质，而目前的岩体损伤张量计算方法都只涉及前2类参数，均没有涉及其变形参数即法向及切向刚度。为此，在前人研究的基础上，基于断裂及损伤理论提出了考虑节理法向及切向刚度的单轴压缩下单条断续节理引起的损伤张量计算公式，进而通过考虑节理间相互作用给出了单组单排或多排节理岩体损伤张量计算公式。其次，以岩石细观动态损伤模型为基础，结合宏细观损伤耦合观点提出了一个能够同时考虑节理几何、强度及变形参数的断续节理岩体动态损伤本构模型。最后，利用该模型讨论了节理参数及载荷应变率等对岩体动态力学特性的影响，认为节理长度减小及摩擦角增大将导致岩体动态峰值强度及弹性模量增大；岩体动态峰值强度及弹性模量则随着节理法向及切向刚度的增大分别减小或增大；而当节理法向及切向刚度按照同一比例增大时，岩体动态峰值强度及弹性模量则是增大的。岩体动态峰值强度与载荷应变率呈正相关。

A dynamic damage constitutive model for rockmass with intermittent joints under uniaxial compression

The intermittent joints have obvious effect on the strength and deformability of engineering rockmass.The joint is assumed to be a kind of macroscopic damage to the rockmass in the damage mechanics,therefore the damage tensor is adopted to describe its effect on the rockmass.Now three kinds of joint parameters such as the geometrical ones,strength ones and deformational ones are proposed in the academic circles to describe the joint physical and mechanical properties.However,the existing calculation methods of the rockmass damage tensor consider only the joint geometrical or strength parameters,not its deformational parameters such as normal stiffness and shear stiffness.Therefore,on the basis of the existing studies,the fracture and damage theory is adopted to propose the damage tensor calculation formula of the rockmass caused by an intermittent joint under uniaxial compression,and then that caused by one row or multi-row of joints in one set is given by considering the interaction of the joints.Secondly,based on the rock mesoscopic dynamic damage constitutive model and the viewpoint of macroscopic and mesoscopic damage coupling,a dynamic damage constitutive model for the rockmass with intermittent joints is proposed which can consider the joint geometrical,strength or deformational parameters at the same time.Finally,the effects of joint parameters and load strain rate on the rockmass dynamic mechanical behaviors are discussed with the proposed model.It is found the decrease in the joint length and the increase in the joint friction angle will increase the dynamic climax strength and elastic modulus of the rockmass.While with increasing the joint normal stiffness and shear stiffness,the dynamic climax strength and elastic modulus of the rockmass decrease and increase,respectively.While when the joint normal stiffness and shear stiffness increase in the same proportion,the dynamic climax strength and elastic modulus of the rockmass increase.The dynamic climax strength of the rockmass has a positive correlation with the load strain rate.