初始含水率对红粘土胀缩变形特性的影响试验研究

红黏土是一种特殊土,其作为路基填料时在季节性干湿循环条件下会发生变形破坏,从而导致一系列路基病害的产生。利用收缩仪和膨胀仪,对不同初始含水率下的重塑红黏土土进行了无荷条件下的干湿循环试验,研究了不同初始含水率下红黏土的反复胀缩变形特征。结果表明:初始含水率及干湿循环次数对红黏土的胀缩变形均有影响。随着干湿循环次数的增加,红黏土绝对膨胀率、绝对收缩率绝对值逐渐增大;相对膨胀率、相对收缩率均越来越小;相同的干湿循环次数下,初始含水率越大,红黏土绝对膨胀率、绝对收缩率越大,对于前3次干湿循环,初始含水率越大,相对膨胀率、相对收缩率越小,而对于3次干湿循环之后,初始含水率越大,相对膨胀率、相对收缩率却越大。红黏土在干湿循环中,发生了不完全可逆的胀缩变形。

Experimental research on the affect of the swell-shrinking deformation of red clay under the condition of different initial moisture content

Red clay is a kind of special soil.When red clay is used to be subgrade filling , red clay will happen Deformation and failure under the condition of the seasonal cycle,then it will lead to a series of roadbed disease. In this article, using the contraction and expansion instrument, the reshaping red clay with the condition of different initial moisture content is texted under the condition of wetting-drying cycle without charge. The repeatedly swell-shrink deformation characteristics of red clay is studied. Test results show that, different initial moisture content condition and different cycles play regularity effects on swell-shrinking deformation of red clay. With the increasing in the number of wet and dry cycles, the absolute value of the absolute expansion and the absolute shrinkage increase,and the relative expansion rate and the relative shrinkage of red clay decrease.The absolute expansion and the absolute shrinkage of red clay is greater under the greater initial moisture content in the same wet and dry cycle.For the first three cycles of wet and dry, the relative expansion rate and the relative shrinkage is smaller,but the relative expansion rate and the relative rate of contraction is greater under the greater the initial moisture content after three cycles of wet and dry. Red clay occur not completely reversible swell-shrink deformation in the dry-wet circulation.