干湿循环下膨胀土裂隙CT试验研究

CT Study on the Fissures of Expansive Soil During Drying and Wetting Cycles

为了对膨胀土裂隙进行定性、定量分析,采用64位螺旋CT仪对重塑膨胀土在干湿循环过程中裂隙演化规律进行了CT试验。运用MATLAB进行图像处理,计算了裂隙图像的平均灰度值、灰度方差及灰度熵。试样的CT图像揭示了裂隙的产生与开展规律,描述了裂隙发育的深度;三维重建后的CT图像清晰描绘了裂隙产生-发育-贯穿的过程;定量分析了裂隙发育程度与图像灰度均值、图像方差、灰度熵的关系,提出了以变异系数来描述裂隙发育规律,由此得出膨胀土裂隙沿深度方向分为裂隙发育、过渡、不发育三个部分的规律。

In order to qualitative and quantitative analysis the fissures of expansive soil, using 64-bit spiral CT in- strument research the evolution of remolded expansive soil fissures in drying and wetting cycles. The use of MATLAB image processing, calculate the average gray value, gray variance and gray entropy of CT images. The CT images re- veal the formation and development law of the fissures and conclude the developing depth;The three-dimensional re- construction of CT images clearly describe the produce,development,throughout process of the fissures. Analysis the degree of fissures with average gray value, gray variance and gray entropy relations, put forward to coefficient of vari- ation to describe the growth law of fissures, obtain the laws that fissures of expansive soil consists of fissures develop- ment part, fissures transition part and fissures undevelopment part following the depth of the sample.