Monitoring and Analysis of Ground Subsidence at the Intersection Area of Expressway 78 and High Speed Rail of Taiwan

• Main Authors: LIN, CHIA-YI, 林家億
• Other Authors: CHANG, MUH-SIUNG
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/2xs89u

碩士 === 國立雲林科技大學 === 營建工程系 === 106 === Chuoswei River Alluvial Fan-Delta (CRAFD) is the largest alluvial plain suffered severe ground subsidence. According to Water Resources Agency, subsidence center was along the coastal area in the past, and is gradually in control in recent years. Currently, the ground subsidence center is moving towards inlands and centered around Huwei, Tuku, Yuanchang and Baozhong townships of Yunlin County. 　　Since Taiwan High Speed Rail (THSR) passes through the severe subsiding are-as of Yunlin, the transportation safety becomes a main concern to general public. The area of current study is located to the southeast of the intersection of Expressway 78 and THSR, where 11 magnetic-type ground subsidence monitoring wells, 7 groundwater observation wells, and one rain gauge have been installed for a long-term on-site monitoring. According to a 3-year and 4-month monitoring data, we found a regularity of fluctuations in groundwater levels and a close relationship among groundwater levels, rainfall, and the ground subsidence of the site. 　　During the monitor period of this study, the embankment of Expressway 78 at the intersection was removed to reduce the effect of embankment weight on the ground subsidence and THSR as well. On-site monitoring showed that the ground at shallow depths had rebounded by about 2~3cm as a result of the removal, while the ground at greater depths (> 60m) were basically unaffected. On-site monitoring also showed that the accumulated compression is around 9~10 cm in aquifers and aqui-tards within the 300-m depth range of the study area, in which the compression in aquifers (sandy and gravelly soils) appears greater than that in the aquitards (silty and clayey soils).