中文摘要：

利用改进的可控制吸力式非饱和土C.K.C循环三轴仪,对反复干湿循环条件下的粉质黏土进行了动三轴试验研究,探讨了其在饱和条件下干湿循环对累积塑性应变与振次关系以及对动强度特性的影响,同时分析了不同基质吸力下反复干湿循环后的动强度特性。研究表明：干湿循环对粉质黏土的变形特性有明显影响,相同动应力及振次条件下干湿循环试样的累积塑性应变小于原始试样;干湿循环后土体的临界循环动应力以及动强度明显增大;反复干湿循环后,粉质黏土的临界循环动应力和动强度随基质吸力的增加而增大,但其随基质吸力增加而增长的速率随基质吸力的增加而减小。干湿循环前后土体的电镜扫描（SEM）试验发现,干湿循环使得土颗粒排列更加紧密,干湿循环过程中试样内部并未出现微裂缝。

英文摘要：

A series of dynamic triaxial tests were performed to measure variations of dynamic behaviors of silt clay subjected to drying-wetting cycles based on the modified unsaturated C.K.C cyclic loader triaxial testing system. The effect of drying-wetting cycles on the dynamic strength and the relationship between ac- cumulated plastic strain and number of loading cycles under saturate condition were studied. The dynamic strength under different matric suctions after repeated drying-wetting were also analyzed. The test results show that drying-wetting cycle has significant influence on the deformation characteristics of silt clay, and the accumulated plastic strain of the specimens subjected to drying-wetting cycle is smaller than that of the original specimens under the same dynamic stress and number of loading cycles; the critical dynamic stress and dynamic strength increase significantly after drying-wetting cycle; and the critical dynamic stress and dynamic strength increase with a reduced growth rate with increasing matric suction after repeated dry- ing-wetting cycle. Scanning electron micrographs show that soil particles are drawn closer together during drying-wetting cycle process; whereas, micro-cracks do not appear in the soil specimens after drying-wetting cycle.