中文摘要：

根据对单轴压缩条件下软岩蠕变特性的分析,引入损伤变量和硬化函数,建立软岩轴向和横向非线性蠕变模型。软岩轴向蠕变的典型曲线分为衰减、等速和加速蠕变3个阶段,分析认为：产生衰减蠕变的原因是岩石力学性质发生了硬化,主要是由于黏滞系数的硬化引起的;产生加速蠕变的原因是岩石发生了损伤软化,主要是由于岩石弹性模量的损伤引起的。软岩蠕变过程的3个阶段是非线性损伤和硬化两种机制并存、互相竞争的结果,采用单一的模量损伤或黏滞系数的非线性变化均不能合理地描述和解析蠕变过程的3个阶段。同时,引入损伤和硬化两种机制后所建立的非线性蠕变模型可以用一个统一的方程描述软岩蠕变过程3个阶段的变形特征,也可以对蠕变过程的3个阶段做出合理解析。将该模型与泥岩及红砂岩的试验曲线进行对比,两者吻合较好。

英文摘要：

　Based on the creep curves of soft rock under uniaxial compression,a damage variable and a hardening function are introduced into creep model to express the nonlinear creep behavior of soft rock.A new nonlinear model for axial and lateral creep is established for soft rock.The typical creep curve can be divided into three phases,which are decelerating creep phase,even creep phase and accelerating one.The hardening of viscosity coefficient is the main cause of the decelerating phase of creep;and the accelerating phase is mainly due to the damage of the elastic modulus.The damage mechanism and the hardening one keep its balance in the even creep phase.It is unreasonable to describe and explain the three-phase creep by using the nonlinear viscosity coefficient only or the damage of elastic modulus.The three-phase creep course is the results of the competition between damage and hardening.With the creep development of soft rock,rock microstructure changes influence upon the mechanical behavior.Those changes are explained by nonlinear damage and hardening variables.A nonlinear creep model is constructed which can describe the three-phase axial creep of soft rock.Furthermore,the creep Poisson′s ratio is introduced into creep model to express the lateral creep behavior of soft rock;and the energy damage variable is used to describe the anisotropic elastic damage.The results of the model and tests for mudstone and red sandstone are perfectly fitted.