基于西原模型的变参数蠕变方程  

Creep equation of variable parameters based on Nishihara model

作　　者：阎岩[1] 王思敬[1,2] 王恩志[1] 

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《岩土力学》2010年第10期3025-3035,共11页Rock and Soil Mechanics

基　　金："十一五"国家科技支撑计划项目(No2006BAK30B02);国家自然科学基金资助项目(No40872152)

摘　　要：岩石材料的蠕变具有明显的非线性特征,在蠕变模型中考虑蠕变参数随应力、时间等因素而变化是解决非线性蠕变问题的方法之一。试验已经证实,应力、时间及渗流等外部条件会引起岩石某些力学参数的改变,因此,将蠕变参数视为变量符合岩石材料的本质属性。以西原蠕变模型为基础,研究了各蠕变参数与应力及时间的关系。根据试验结果,通过非线性最小二乘法从蠕变试验数据中求出不同应力作用下不同时刻的各个蠕变参数,再根据参数随应力、时间的分布规律经非线性拟合得到各蠕变参数与应力及时间的表达式,进而可得到变参数的蠕变方程。蠕变参数的变化是岩石非线性特征的充分体现,从损伤力学的角度来讲,蠕变参数的变化反映了岩石内部损伤不断加剧、累积,材料特性不断劣化的演变过程。The creep property of rock material is nonlinear obviously, one of the ways to solve nonlinear creep problem is to consider the parameters in creep model varying with stress and time. Some experiments have proved that the stress, time and outside conditions such as seepage will cause the change of some mechanical parameters of rock; so taking the creep parameters as variables accord with the essential attribute of rock material. The relation between stress, time and each creep parameter was investigated based on the Nishihara creep model. First of all, each creep parameter of different times under different stresses was figured out from experiment results by nonlinear least square method; and then the expressions of creep parameters vary with stress and time were put forward by nonlinear curve fitting of the creep parameters＇ distribution; finally form the creep equation with variable parameters by these expressions. The variable creep parameters are reflections of nonlinear characters of rock creep, from the damage mechanics＇ point of view, the changes of creep parameters reveal the accumulation of rock interior damage and the deteriorative process of material properties.

关 键 词：岩石蠕变 非线性 西原模型 变参数 蠕变方程 

分 类 号：TU452[建筑科学—岩土工程]