考虑含水劣化的泥质粉砂岩单轴蠕变特性研究

基于不同含水状态下T2b2泥质粉砂岩蠕变特性的试验研究结果,建立蠕变模量与含水率之间的数学关系式,表明含水率越大蠕变模量越小.将岩石的含水损伤定义为瞬间弹性损伤和长期蠕变损伤,结合试验结果确立了损伤变量和损伤演化方程,并基于泥质粉砂岩非线性蠕变方程建立了可考虑含水损伤的岩石蠕变模型.针对含水率恒定与变化两种情况下的理论和试验结果分别进行了对比分析,结果表明:①含水率恒定情况下,理论曲线和实验曲线的变化趋势是一致的;②变含水率情况下,理论曲线是介于饱和状态和干燥状态蠕变曲线之间的一种特殊曲线,不同吸水速率对应的瞬间弹性应变与干燥状态相等;吸水速率越大,初始蠕变速率越大,蠕变应变量也越大;吸水速率越小,岩石进入稳定蠕变阶段所需时间越长.

Study on the creep properties of T2b2 siltite in terms of the damage law induced by water

Based on the study of creep property of T2b2 siltite under different moisture content,the mathematical relationship between creep modulus and moisture content is presented,which shows that the higher moisture contents the smaller creep modulus.Damage of siltite induced by water is divided into the instantaneous elastic damage and long-term creep damage,and the damage variables and damage evolution law are presented too.Consequently,based on the study to the nonlinear creep model of siltite,the creep model of rock considering water damage is presented.Comparing the theoretical and experimental results with constant and variant moisture,it is found that,① the theoretical curves and experimental curves are varied with the same trend when the moisture is invariable;② theoretical curve with variable moisture is a kind of curve between the saturated and dry case;the instantaneous elastic strain under different water absorbing rate is the same as that in the dry state.With the growth of water absorbing rate,the initial creep rate and creep strain are increased,and the time that creep deformation enters into the stable stage is decreased.