大理岩弹塑性耦合特性试验研究

Experimental research on elastoplastic coupling character of marble

大量研究表明,岩石经历塑性变形时其弹性参数会发生变化,即存在弹塑性耦合现象。为了研究岩石的弹塑性耦合特性,进行了两种大理岩的循环加、卸载试验。试验结果表明:与常规试验对比,循环加、卸载试验对岩石的变形、强度及破坏形态影响较小;弹性参数随塑性变形的变化显著,考虑弹塑性耦合时,弹性参数取体积模量和剪切模量更为合适;基于Mohr-Coulomb屈服准则,计算得到了强度参数,即黏聚力和内摩擦角随塑性内变量的演化规律。所得结论将为岩石弹塑性耦合本构模型的建立提供基本的试验支持。

A lot of research work shows that when rock undergoes plastic deformation,its elastic parameters vary.In order to study the elastoplastic coupling characteristic of rock,cyclic loading experiments on two kinds of marbles are carried out.The experiments show that comparing with conventional triaxial experiments,cyclic loading experiments do not influence the deformation and strength of the rocks.The elastic parameters obviously vary with plastic deformation.When taking the elastoplastic coupling character into consideration,bulk modulus and shear modulus are more suitable to be selected as elastic parameters than elastic modulus and Poisson ratio.The variation of the parameters of strength with plastic internal variable is also obtained under the hypothesis of Mohr-Coulomb yield criterion.The results can provide experimental basis for the furthur study on the elastoplastic coupling constitutive model of rock.