黄土非饱和湿陷变形的计算模型

A model for predicting the unsaturated collapse deformation of loess

针对黄土含水量增加可发生变形的特点,提出一种考虑黄土非饱和湿陷变形的计算模型。该模型将基质吸力作为湿陷的原因,以非饱和渗透和非饱和变形理论为基础,并考虑了水分在土层内的分布对湿陷变形的影响。以甘肃黑方台灌区自重湿陷性黄土为研究对象,进行了不同含水率的侧限压缩试验和土水特征曲线的测试,建立非饱和渗透模型,利用上述计算模型得到了不同时间的场地湿陷变形总量和年变形量。其总湿陷量同实际结果基本一致,且2007~2011年湿陷量和累积湿陷量同文献中采用INSAR技术得到的结果相近。通过和规范建议的湿陷系数法计算结果对比表明,考虑黄土的非饱和湿陷变形会得到较为符合实际的结果。

Since loess tends to collapse when the water content increases,this research puts forward a new method to calculate the collapse deformation. It regards the matric suction as the cause of collapse,is based on the unsaturated deformation and unsaturated seepage theory and considers the effect of moisture distribution on collapse. The method is employed to calculate the collapse deformation of the self-weight collapsible loess in the Heifangtai irrigation area. Oedometer tests on samples with different moisture content and tests measuring the soil water characteristic curves（ SWCC） were performed and the unsaturated seepage model simulating the irrigation process since 1967 was also built to obtain the parameters needed in the method. The results show that the accumulate deformation of 2014 is in agreement with the actual values,and the annual and accumulative deformation during 2007- 2011 are close to those obtained by INSAR technique in the literature. What＇s more,comparison between the total deformation of the paper and that obtained through the method recommended by the regulation shows that taking the unsaturated collapse deformation into consideration will be helpful in obtaining relatively accurate deformation.