非饱和黄土弹性模量与饱和度关系模型研究

A Model of the Relationship between Elastic Modulus and Saturation of Unsaturated Loess

为研究非饱和黄土弹性模量与饱和度的相关性,采用一种基于吸应力理论与粒子图像测速技术相结合的方法对典型非饱和马兰黄土重塑样品的弹性模量随饱和度变化规律进行测试与分析。该方法通过自主研制的多功能摄影测量装置获取饼状土样从饱和状态至干燥过程中的高分辨率数码图像与含水率变化数据,同时使用压力板仪与单轴压缩仪分别测试试样的土水特征曲线与泊松比。结合吸应力理论与极坐标形式应力-应变关系理论计算土样在不同饱和度状态下的弹性模量。3种干密度重塑土样在自然风干过程中的弹性模量变化测试结果表明,马兰黄土的弹性模量随饱和度降低而呈指数增大,提出了拟合弹性模量与饱和度关系的数学模型。

In the aim of investigating the relationship between elastic modulus and saturation of unsaturated loess,a testing method based on the suction stress theory and particle image velocimetry technique is employed to test the variation of elastic modulus with saturation of typical remolded Malan loess.The high-resolution digital images and moisture content data of flat cylindrical soil samples subjected to dessication from saturation to dry condition are obtained by this method using a self-made multi-function photogrammetric device.Meanwhile,the soil-water characteristic curve and Poisson’s ratio of the samples are measured by pressure plate instrument and uniaxial compression instrument,respectively.Furthermore,the elastic modulus of unsaturated soil with different water content are calculated based on the suction stress theory and the stress-strain relations in polar coordinates.The test data of samples with different dry densities during air drying process indicates that the elastic modulus of Malan loess samples increase exponentially with the decrease of saturation.A mathematical model for the relationship between the elastic modulus and saturation degree is proposed.