对饱和岩石随温度变化情况进行实验研究,其结果显示:饱和岩石随温度升高,模量、波速减小;随温度继续升高,模量、波速又随温度升高而增大。这一规律是热激活弛豫波动理论模型的佐证。将这一温度效应引入隐含内力的细观PM(Preisach-Mayergoyz)模型中,则模型中的模量Ki变为与温度相关的函数Ki(T)。温度T的变化同样会引起PM空间中滞回细观单元(HMU)特征长度和PM空间HMU密度分布的变化,从而引起宏观模量的变化,为此建立温度对PM空间非经典单元(NCU)密度影响的函数关系。在此基础上进行温度效应的细观研究,且对循环加载滞回圈的温度效应进行模拟,取得滞回圈随温度升高向应变增大方向移动,滞回圈模量降低,随温度继续升高,滞回圈又随温度升高朝低应变方向移动,模量增大。这一细观模拟结果与国内外相关实验结果是一致的。
The experiments,in which the variation of mechanical properties for saturated rocks with the change of temperature had been studied,show that the moduli and wave velocities of fluid-saturated rocks decrease as temperature increases,and as temperature continues to raise,the moduli and wave velocities turn to increase.This is the temperature effect,and it proves the rationality of the wave model with thermal activated relaxation.By introducing this temperature effect into the mesoscopic PM(Preisach-Mayergoyz) model with internal bonding forces,the modulus Ki turns to be a temperature dependent variable,that is,Ki(T).The change of the temperature will cause the variation of characteristic length of hysteretic mesoscopic units(HMU) in PM space and the change of the PM space density.Thus the macroscopic elastic moduli shift too.Based on these,the density distribution function,with the influence of temperature,of the non-classical units(NCU) in PM space is obtained.The temperature effect is studied in meso scale,and temperature influence to the hysteretic loops under cyclic loading is simulated.The hysteretic loops move to bigger strain area and the moduli decrease as temperature increase.While temperature continues to rise,the hysteretic loops move backward,and the moduli turn to increase.The simulated results are consistent with the corresponding experimental results,whether the experiments were done by domestic researchers or foreign researchers.