原状膨胀土损伤演化的三轴CT试验研究

本文利用和计算机断面成像CT机配套使用的非饱和土三轴仪，对非饱和原状膨胀土在三轴剪切试验过程内部结构的变化进行了动态、定量和无损地量测，得到了土样内部损伤结构演化的清晰的CT图像和相应的CT数据.试验结果表明：原状膨胀士内部存在裂纹、空洞、裂隙面和软弱面等结构缺陷，初始损伤程度较大；剪切引起的损伤演化明显，且土样所受的吸力和净围压均对损伤演化有影响；原状膨胀土在吸力和净围压较低时的剪胀和软化特性主要是由于结构损伤的演化引起.

Study on damage evolution of natural expansive soil with computerized tomography during triaxial shear test

The interior structure change of unsaturated natural expansive soil in triaxial test is monitored instantaneously, quantitatively and undamaged by means of computerized tomography (CT) technology. The clear CT images and relevant data reflecting the damage evolution of soil samples are attained. The result shows that some damage structures such as crack, tiny hole, flaw, weak plane, etc. exist in natural expansive soil. The damage evolution due to shearing is obvious and effected both by suction and net mean stress of soil. The dilation and softening characteristics of natural expansive soil while shearing under low net mean stress and suction are mainly caused by the evolution of damage structure.