Model Test Study On Swelling Rock Slope Under Different Rainfall Modes

Continuous rains and wet-dry cycles are common phenomena in the nature, and they often have effects on slope. Every effect will affect the slope characteristics; In addition, the force of rainfall poses a larger influence on the slope, mainly reflected in the change of deformation and water content. Therefore, studying on swelling rock slope under continuous rainfall and wet-dry cycles with different rainfall force is of great significance in mastering the characteristics of swelling rock slope.In order to do the experimental study on the response modes of slop under the circumstance of continuous rainfall and wet-dry cycles. I designed two experimental systems, one is continuous rain and another one is wet-dry cycles experiment system. By monitor the water content and the displacement to analysis the regulation of slop. According to experiment results, under the continuous rainfall, deformation was very large in early number times and became quite small after then. After a few rains, slop had the movement of level direction. The change of volume moisture had the layer characteristics, surface moisture got response first, and the deep place started change after many times of rains. After several rains, the Water content in deep place was beginning to remain stable, the water flow direction shift from bidirectional initially to unidirectional. Under the wet-dry cycles, with cycles going, Horizontal deformation change from the small at the beginning to large quickly, the deformation inclined to angular surface started to accumulate, the influence depth was increased little by little and keep stabilization after several times. The water flow direction was bidirectional, and the sudden strengthen rainfall can significantly increase the deformation and influence depth.In continuous rainfall mode, early rainfall has a greater effect on slop than the later rainfall, and it may occur the large deformation damage. However, in wet-dry cycles mode, it was near impossible to have damage in the early rainfall, But the first big rain after several long times cycles posed large influences on the slop, it was much possible to have damage in this big rain. With some more cycles, the deformation was still increased but its effect on the slop got weakened. Slope in continuous rainfall mode appeared mud, soften and damage in the foot in the initial rains, but in the later rainfall, it became balance and had no obvious damage in the slop; Slop appeared the shear slide destructive under the load in the last. While in the mode of wet-dry cycles, the mud,fracture development and rock integrity destructive appeared in the slop, the first destructive was appeared in the form of draft slide in the foot of slop, and the last damage mode was largely range surface slide destructive.