基于DIC技术的红黏土干缩开裂试验研究

Experimental study on dry shrinkage cracking of red clay based on DIC technology

红黏土在干燥条件下极易产生裂隙,并由此引发大量的红黏土工程地质病害.以湖南邵阳地区红黏土为研究对象,通过室内干缩开裂模型试验,借助数字图像相关技术(DIC)分析土体表面的位移、应变的发展及与裂隙演变的关系.试验结果表明:DIC技术在无损试样前提下可采集土样表面位移及应变信息;在干燥初期土样表面开始产生拉应变,拉应变达到峰值后便逐渐减小,最后转变为压应变并随时间增大;土样表面裂缝两侧的位移及应变均大于土样区块中心位移及应变,且土表各处位移及应变均不相同;在干燥过程中土样表面一直产生竖向下沉,且不同位置的竖向位移大小也不相等.

Red clay is easy to produce cracks under the action of drying,which leads to a large number of red clay engineering geological disasters.This paper takes the red clayin the district of Shaoyang,Hunan Province as the research object,through the indoor drying shrinkage cracking model test,with the help of digital image correlation technology,analyzes the development of displacement and strain on soil surface and the relationship between them and fracture evolution.The experimental results show that:digital image correlation technology can collect the surface displacement and strain information of soil sample under the premise of non-destructive sample;tensile strain begins to appear on the surface of soil sample at the initial stage of drying,and then gradually decreases after the tensile strain reaches the peak,and finally changes into compressive strain and increases with time;the displacement and strain on both sides of the crack are greater than the displacement and strain on the center of the soil block,and the displacement and strain on the surface of the soil block are different;during the drying process of soil samples,the surface of soil samples always sinks vertically,and the vertical displacement at different positions is not equal.