| Summary: | 碩士 === 國立屏東科技大學 === 土木工程系所 === 102 === In Taiwan, landslides on compacted slopes easily occur due to heavy rains brought by typhoons. This may be attributed to inadequate compaction degree or poorly controlled initial moisture content. Under these circumstances, slope failure occurs after rainfall seepage. Therefore, artificial rainfall simulation experiments were carried out in the laboratory to discuss the effects of different degree of compaction, initial compaction moisture content and the rainfall intensity in unsaturated compacted soil slopes subjected to rainfall. During these tests, the soil moisture and suction meters were buried into the soil to monitor the variation of moisture content and matric suction. In this study, the relationship between rainfall duration and the time factors of matric suction was discussed under different infiltration depth.
The results show that the lower degree of compaction together with the larger porosity makes infiltration rate higher, the saturation time of rainwater infiltrating slope faster, and the drop time of matric suction rapider. Besides, in consequence of fast descending slope of suction, the destructive scale is greater than that at the high degree of compaction. On the other hand, with increase in initial moisture content, the soil structure transforms. Extending time of rainwater infiltration induces the delay of decline in matric suction time and slows down suction slope, which facilitates the stability of the slope.
In addition, when the rainfall intensity is greater than the permeability of soil, rainwater dropping on the surface of the slope results in the runoff, prompting the destructions such as the surface erosion and the loss of pellets. That is because when it rains heavily, the surface of runoff becomes greater, which consequently enlarges the destruction area of slopes.
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