膨胀土的收缩与开裂特性试验研究

Research on the shrinking and cracking properties of expansive soil

膨胀土因其高胀缩性带来很多工程问题,膨胀土的收缩及开裂对工程危害更大。通过对安康膨胀土进行收缩试验与开裂试验,研究膨胀土的收缩变形特性与开裂规律。结果表明:膨胀土的收缩变形受初始含水率的影响显著,受干密度影响较小,给出了计算收缩应变的公式;非饱和膨胀土的收缩变形存在各向异性,以侧向变形为主,并随着含水率增加向各向同性过渡;裂缝的长度、宽度服从对数正态分布,面积服从负指数分布,交点服从均匀分布,裂缝的交角以90°左右为主;厚度越大、温度越高开裂含水率越高。

Expansive soil has brought about numerous engineering problems due to its behavors of expanding and shrinking, the shrinking and cracking of expansive soil can greatly endanger engi- neering works. The shrinking deformation behaviors and craking laws of expansive soil are studied through the tests of Ankang shrinkage soil and cracking. The testing results indicate that the shrinking ceformation of shrinkage soil is obviously subjected to the influence of initial moisture content rate and to the less influence of dry density. Also, the formulk to calculate shrinkage strain is given out. There exists the anisotropy in shrinkage deformation of unsaturated expansive soil, with the side deformation in the transformation to isotropy,The lengrh and width of crack- ing are found to follow the logarithmic normal distribution, area conforms to the negative expo- nential distribution, crossing points obey the uniform distribution, and crossing angles of cracks are mostly around 90°. Accordingly,the larger the thickness is ,the higher the temperature, and the higher the moisture content rate in the cracks will be.