饱和黏土的一维热固结特性试验研究

通过室内试验,研究了饱和黏土在不同温度作用下的固结效应.结果表明:温度对土颗粒的膨胀作用和孔隙比的收缩作用影响较小;高温作用下发生的热膨胀在一定程度上阻碍了变形的发生,高温条件下压缩指数较低温条件下有减小的趋势.但渗透性的增强使得该现象逐渐减弱.随着温度的升高,先期固结应力均随之减小.通过反分析得到了两种黏土的材料参数γ.材料参数γ越大,相同温度下的归一化先期固结应力越小.温度越高,水溶液的黏度越低,越容易被排出,其渗透系数越大,超静孔隙水压的消散越快,所以超静孔隙水压随着温度的升高而减小.渗透系数随着孔隙比的升高而升高.粒径较大试样的渗透系数大于粒径较小试样的渗透系数.

Experimental Study of One-Dimensional Thermal Consolidation of Saturated Clays

The consolidation properties of two saturated clays were studied by laboratory tests under different temperatures. Results showed that: the effect of temperature on the expansion of soil particles and the contraction of void ratio was small; high temperature induced thermal expansion could affect the deformation to some extent， so the compression index became smaller as the temperature increased. However， such an effect diminished due to better permeability; the pre-consolidation stress decreased with increasing temperature. The material parameter γ for two clays was calculated by back analysis. The clay with larger γ had smaller normalized pre-consolidation stress under the same temperature; the higher temperature led to less excess pore water pressure due to higher permeability coefficient because the viscosity of pore water at higher temperatures became weaker. It was found that the permeability coefficient increased with larger void ratio and grain size.