Numerical Analysis of Rainstorm-induced Instability of Reinforced Soil Structure

• Main Authors: Guan-Ping Wang, 王冠評
• Other Authors: Kuan-Yung Chang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/ja5m5x

碩士 === 國立臺北科技大學 === 土木與防災研究所 === 101 === In recent years, reinforced soil structures have been widely applied to all types of retaining walls and slope stabilization construction in Taiwan. This structure reduces costs, shortens construction schedules, enhances seismic resistance, and reduces CO2 emissions. In addition, the adoption of this structure greens, beautifies, and harmonizes ecological environments, thus achieving the green concept of sustainable development. However, slopes have encountered frequent large-scale landslides and reinforced soil structures have been damaged because cloudbursts are triggered by global warming and abnormal climate changes. This study utilized STEDwin to analyze the effects of precipitation and saturation on the stability of reinforced soil structures. Analysis results were examined and improvements were suggested. According to the analysis results, although reinforced soil structures could increase slope stability, a circular sliding analysis showed that sliding surfaces that damaged the reinforced soil structure were caused by the toes of slopes that extended to backfilling areas (interfacial failure). Compared to circular sliding analysis results, the interfacial analysis on cloudburst models demonstrated that a reinforced soil structure with a 45° slope had a 57% reduction at maximum in factor of safety (FoS); a reinforced soil structure with a 70° slope had a 16% reduction at maximum in FoS; and no significant Fos change was observed for a reinforced soil structure with a 80° slope. In addition to partial analyses on reinforced soil structures, analyzers have to thoroughly investigate the stability of the entire reinforced soil structure (the upper slope, lower slope, and overall slope); otherwise stability may be miscalculated and increase risks of failure. Reinforced soil structure failure often occurs in the presence of cloudbursts. Because of poor drainage of the structure and the cut-and-fill interface as a plane of weakness, the overall structure may experience sliding failure without damaging the structure itself. Therefore, the design of the reinforced soil structure emphasize the enhancement of the drainage of reinforced soil structures and the anchoring force of geogrids. This enhancement will reduce the incidence of interfacial failure and increase the stability of reinforced soil structures.