关键词: 干湿循环, 红黏土, 裂隙, 强度劣化

Abstract: The problem of the crack development and the shear strength deterioration of the red clay soil under the dry and wet cycles has gained widely attention. The crack development and the shear strength deterioration of the red clay soil with the change of the degree of compaction, water content and times of dry and wet cycles has been studied by the laboratory test in this paper. The results show that the moisture content of the red clay soil with the same degree of compaction has significant effect on the crack development. The grid cracks develop in the red clay soil with the low water content, while the long and wide strip cracks develop in the red clay soil with high water content. It is also found that the crack ratio and the crack length ratio raise with the times of dry and wet cycles. the higher the water content and the low density of the red clay, the greater the crack ratio and the crack length ratio and the higher the crack development degrees. The cohesion and the internal friction angel of the red clay soil with different water content decrease rapidly at the first and then gradually stabilize. The higher the degree of compaction of the red clay soil with same water content, the faster the decay ratio of the cohesion and the internal friction angel of the red clay soil. Moreover, the results also show that the decrement of the cohesion and the internal friction angel of the red clay soil with 4 times of the dry and wet cycles can be ignored and the average decay ratio of the cohesion and the internal friction angel with the different degree of compaction can obtained which indicate that dry and wet cycles has more significant effect on the cohesion than the internal friction angel.

Key words: Dry and Wet Cycles, Red Clay, Crack, Shear Strength Deterioration