| Summary: | 碩士 === 國立中興大學 === 水土保持學系 === 92 === ABSTRACT
Water plays an important role in most slope stability problems. Rainfall infiltration not only increases the driving force to fail but also decreases the resistant strength of soil. Knowledge of groundwater flow is essential for the analysis of slope stability. The process of infiltration into the slope due to rainfall and the distribution of pore water pressure are examined by finite element method. An extended Mohr-Coulomb failure criterion is used to allow for the shear strength under the change of matric suction. The results indicate that slope stability is influenced by rainfall intensities. However, there exists a critical condition of the influence of rainfall intensity on slope stability and this condition is dominated by the permeability of saturated soil. In addition, the influence of rainfall pattern on slope stability is discussed as well. The results indicate that the earlier peak of rainfall intensity has earlier change in safety factors, but the later
peak of rainfall intensity has greater change in safety factors. On the other hand, the instability of slope can reach earlier by antecedent rainfall, and the following heavy rainfall will make failure of slope possible. This work also studies the effect of degree of slope, and we can obtain that
with the soil parameters selected herein, when the degree of slope is smaller than 50 degree, the slope will not be easy to fail. However, as the degree of slope increases, the failure of the slope will occur very easily.
Key words: slope stability, rain infiltration, seepage, matric suction
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