基于统计损伤原理的岩石加速蠕变模型研究  

Accelerated creep model for rock based on statistical damage principle

作　　者：刘文博 张树光[1,2] 陈雷 孙博一 路平平 LIU Wen-bo;ZHANG Shu-guang;CHEN Lei;SUN Bo-yi;LU Ping-ping(Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering,Guilin 541004,China;School of Civil and Architectural Engineering,Guilin University of Technology,Guilin 541000,China;School of Civil Engineering,Liaoning Technical University,Fuxin 123000,China)

机构地区：[1]广西岩土力学与工程重点实验室,广西桂林541004 [2]桂林理工大学土木与建筑工程学院,广西桂林541004 [3]辽宁工程技术大学土木工程学院,辽宁阜新123000

出　　处：《岩土工程学报》2020年第9期1696-1704,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51274109);广西自然科学基金项目(2020GXNSFAA159125)。

摘　　要：针对现有蠕变理论模型无法较好地描述岩石黏塑性阶段的加速蠕变特性及如何确定岩石加速蠕变阶段的启动条件等问题,对取自阜新恒大煤矿深部围岩开展了室内三轴蠕变试验,分析了岩石在蠕变变形规律。为了使建立的模型不仅较好地描述岩石蠕变特性,也可以较好与经典蠕变曲线各阶段相对应,通过经典的蠕变变形示意定义了各个分段临界点的指标,进而建立了一种考虑加速蠕变变形的新型岩石黏弹塑性蠕变模型。结果表明:在考虑岩土类内部缺陷发育的基础上,采用统计损伤理论来构建岩石加速蠕变模型,使得试验曲线也与模型曲线具有良好的吻合度,说明了基于统计损伤原理建立的岩石加速蠕变模型,来反映岩石蠕变全过程曲线是正确的;这也证明了采用统计损伤变量和经典蠕变曲线定义的临界点指标的正确性。岩石蠕变加载过程也是一种岩石内部微元体损伤破坏的过程,在材料微观结构上表现为不可逆性。通过将蠕变曲线分阶段,来定义分段临界点的损伤变量的表达形式,结合统计损伤理论和Perzyna黏塑性模型,对传统的西原体模型进行适当的改进,建立非线性蠕变损伤模型,从而更好地体现了损伤受岩石内部应力应变状态影响和损伤演化规律。Aiming at the problems that the existing creep theoretical models cannot describe the accelerated creep characteristics of the viscoplastic phase of rock and how to determine the start conditions of its accelerated creep phase, the triaxial creep tests are carried out on the deep surrounding rocks taken from Hengda Coal Mine of Fuxin. The creep deformation laws of rock are analyzed. In order to make the model describe the creep characteristics of the rock well and correspond to each stage of the classic creep curve, and by defining the index of each segment critical point based on the classical creep deformation, a new visco-elastoplastic creep model for rock considering accelerated creep is established. The results show that on the basis of considering the development of internal defects in rock and soil, the statistical damage theory can be used to formulate the accelerated creep model for rock. It is proved that the proposed model based on the statistical damage principle is correct in reflecting the whole curve of rock creep. The correctness of the critical point index defined by statistical damage variables and classic creep curves is also proved. The loading process of rock creep is also a kind of damage and destruction process of micro-elements inside the rock, which is irreversible in the material microstructure. By dividing the creep curve into stages, the expression form for the damage variable of the segmentation critical point is defined. By combining the statistical damage theory with the Perzyna viscoplastic model, the traditional Nishihara model is appropriately improved so as to establish the nonlinear creep damage model to better reflect the influences of the stress and strain state of the rock and the damage evolution laws.

关 键 词：统计损伤理论 黏弹塑性蠕变模型 启动条件 加速蠕变 阈值 

分 类 号：TU451[建筑科学—岩土工程]