A Study on Mechanism of Slide through Slope Monitoring System

• Main Authors: Jie-Wen Chen, 陳玠文
• Other Authors: Mu-hsiung Chang
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/13178142926508617895

碩士 === 國立雲林科技大學 === 營建工程系碩士班 === 89 === A Study on Mechanism of Slide through Slope Monitoring System Taiwan is located in the conjunction area between Eurasia Plate and Philippine Sea Plate. As a result, the geology condition of the island is complex and the earthquake activity is frequent. In addition, Taiwan is subjected to a great amount of rainfalls each year; most of them are concentrated in the summer season. Due to the inherited reasons as well as other human factors, the hill slopes in the island are vulnerable and landslide incidents occurred occasionally. Despite the causes may be complicated, it is worthwhile to study the mechanism and the inter-related factors of any potential landslides by the installation of proper monitoring measures. Once the mechanism can be fully understood, a simple and practical warning system can be set up and unnecessary losses can be mitigated. Typhoon Herbert swept the entire island and brought abundance of rainfalls at the end of July 1996. During that time, significant landslides occurred in a hilly area (50 ha), called “Woo-Wan-Tzai” of Chiai County, which had caused lots of subsidence and cracks of a local main traffic artery, Province Road No.18, between the mileage 28K+900 and 31K+500. The study has initiated since the beginning of 2000 by installing several slope monitoring equipment and providing persistent monitoring of ground movements, groundwater conditions and rainfalls. With the aid of theoretical analysis and laboratory testing, the study found the relation between the slope movements and the rainfall, as well as the groundwater conditions are intimated. The monitoring results showed the natural creep of the hill slopes can be up to 0.015-0.400 mm/day, with no obvious rainfall being recorded. If slope movement increases noticeably, the required accumulated rainfall should be at least about 100-270mm. The study concluded the mechanism of slide for the mid and southern slopes was attributed to the infiltration of rainfall, which tended to increase the driving force and soften the shear resistance of the sliding mass due to soaking. In addition, the increase of groundwater level further decreased the effective stress and hence the shearing resistance along the sliding surface. However, rainfall had less effects on the fluctuation of groundwater lever in the northern slopes. The movements of these slopes were mainly due to the increase of driving weight and the softening of shear resistance of sliding mass as the results of rain water infiltration.