基于白光干涉技术的黏性土真实接触面积细观试验研究

Meso-scale Experimental Study on Real Contact Area of Cohesive Soil Based on White Light Interference

为了揭示黏性土受压时的真实接触面积及细观物理参数的变化规律,利用白光干涉技术测量黏性土在高压应力作用下的真实表面轮廓,对不同压应力作用下表面轮廓点云数据进行分析,并通过Logistic函数推导极限压缩状态下的极限值。结果表明:压缩后的黏性土真实表面轮廓呈偏态分布,存在黏性土颗粒的支撑中心及颗粒压缩接触域;在106~529 MPa的压应力作用下,黏性土实际接触面积占截面面积的比例为0.375~0.431,表观孔隙率为52.5%~55.4%,随着压应力增大,孔隙范围有集中趋势且存在极限值;在支撑中心上、下1倍粒径范围内,表面轮廓分布存在极限渐进值。

To reveal the variation law of real contact area and meso-physical parameters of cohesive soil under compression,white light interference technique was used to measure the real surface profile of cohesive soil under high compressive stress.According to the particle size of cohesive soil,the surface profile point cloud data under different compressive stresses was analyzed,and the limit under limit compression state was derived by using Logistic function.The results show that the real surface profile of the compressed cohesive soil is skewed with the support center of cohesive soil particles and the compression contact area of particles.Under the stress of 106 MPa to 529 MPa,the proportion of real contact area of cohesive soil to cross section area is from 0.375 to 0.431,and the apparent porosity is from 52.5%to 55.4%.As the stress increases,the pore range has a tendency to concentrate and there is a limit.There is a limit asymptotic value on the surface profile distribution within the particle size range of 1 times the support center.