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以南水北调中线工程陶岔引水渠坡的膨胀土为研究对象,利用X-Ray CT断层扫描技术机配套使用的CT-多功能土工三轴仪,对不同损伤位置的3组重塑膨胀土样进行控制吸力为50kPa和净围压为100kPa的CT-三轴压缩试验.通过CT扫描设备获得试验过程中土样内部结构的实时演化情况.试验结果表明:不同损伤位置的圆柱孔对土体的强度特性和变形特性有分阶段、不同程度的影响,轴向应变小于11%时,相同损伤面积不同损伤位置的试样的偏应力-轴向应变关系曲线形式基本重合;但当轴向应变大于11%以后,6mm中孔试样表现出与其他两个试样不同的明显的应变软化特征.而体应变-轴向应变关系曲线只在应变小于6%范围内表现出基本相似的变化规律,后阶段6mm中孔试样体变速率加剧.同时在剪切过程中,损伤位置也影响土体内部结构的演变规律,损伤位置越靠近中间的试样其ME值和SD值都将越大.
Taking the expansive soil of Taocha diversion channel slope in the midline of South-to-North Water Diversion Project as the research object, three groups of remolded expansive soil samples at different damage locations were analyzed using the CT-multifunctional geotechnical triaxial apparatus used with the X-Ray CT tomography machine CT-triaxial compression test with controlled suction of 50kPa and net confining pressure of 100kPa.The real-time evolution of the internal structure of the soil sample during the test was obtained by the CT scanning equipment.The results show that the strength of the cylindrical body at different damage locations The characteristics and deformation characteristics of the specimens have different stages and degrees of influence. When the axial strain is less than 11%, the deviatoric stress-axial strain curves of the specimens with the same damage area are basically coincident. However, when the axial strain is greater than 11 The 6mm mesoporous samples show distinct strain softening characteristics which are different from those of the other two samples, while the curves of bulk strain and axial strain show similar changes only in the range of strain less than 6% During the shear process, the damage location also affected the evolution of the internal structure of the soil, and the closer to the middle of the damage location, the ME value and the SD value were both Greater.