Safety Factor of Homogeneous Unsaturated Slopeby Slice Method

• Main Authors: Hsuan-Hao Pai, 白軒豪
• Other Authors: Yu-Ning Ge
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/13981844763073311784

碩士 === 國立臺灣大學 === 土木工程學研究所 === 102 === In Taiwan, more than two third of land is mountain. As the country continues to develop, people’s living places gradually expand into mountain area. Rainstorm and typhoon often occur in summer and cause severe damage. Thus, safety analysis in mountains becomes more and more important. When analyzing the factor of safety (FS) of a slope by conventional limit equilibrium method, the slope is divided into a dry part and a fully saturated part. Although a conservative FS can be obtained, it costs more in construction. On the other hand, soil does not suddenly become fully saturated from a dry situation. Saturation always changes from 0% to 100% gradually. As a result, there is an unsaturated part in the slope. From the literature, a special stress exists in the unsaturated soil, which is named “suction stress“. Suction stress helps increase the effective stress in the soil. Once effective stress gets higher, the FS of slope will increase too. It not only makes the analytical result suitable in the current situation, but also reduces the budget in the construction procedure. The research conducts seepage analyses within the slope by Seep/w to get the volumetric water content distribution and pressure head distribution in the domain. Suction stress is than calculated analytically. Finally, limit equilibrium analyses, including Ordinary Method and Simplified Bishop Method, are carried out. The results are compared with the published data in literature.