滑带土分数阶损伤蠕变本构模型研究

Study on fractional damage creep constitutive model of slip zone soil

为研究滑坡滑带土的蠕变特性,采用ZLB-1型三联直剪蠕变仪对露天矿滑带土进行分级加载蠕变试验,并基于分数阶微积分及损伤力学理论建立了分数阶损伤蠕变本构模型.结果表明:在同一时刻,剪切蠕变变形随剪切载荷的增加而增大;当剪切载荷低于长期强度时,试样发生衰减蠕变;当剪切载荷高于长期强度时,试样发生等速蠕变及加速蠕变;滑带土蠕变的非线性程度随时间增加而提高.所建立的分数阶损伤蠕变本构模型对滑带土试样蠕变曲线的拟合决定系数在0.951 6～0.999 1,拟合精度较高,对蠕变三阶段都能够进行很好的描述.

In order to study the creep characteristics of landslide slip zone soil,the ZLB-1 triad direct shear creep instrument is used to do the experiment of creep behavior of landslide slip zone soil in open pit mine under graded loading.Fractional damage creep constitutive model is established on the base of fractional calculus and damage mechanics theory.The result shows that shear creep deformation increases with the growth of shear load at the same time;attenuated creep occurs when shear load is lower than long-term strength;isovelocity creep and accelerated creep occur when shear load is higher than long-term strength;and the nonlinearity of creep of sliding zone soil increases with the growth of time.The determination coefficient of the fitting curve is between 0.951 6 and 0.999 1,so that the fitting precision of the new type creep constitutive model is relatively high and the three stages of creep can be well described.