Investigation of Land Subsidence at the Intersection of Provincial Highway 78 and High Speed Rail

• Main Authors: Feng-Yi Dai, 戴鳳儀
• Other Authors: Wen-Juinn Chen Ph.D.
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/32284667304545991986

碩士 === 國立嘉義大學 === 土木與水資源工程學系研究所 === 103 === The biggest worries about driving safety are the embankment subsidence since Taiwan High Speed Rail (THSR) started transportation and service. On March 7, 2011, the location of the most serious subsidence problem occurred at the cross section along the THSR line and the Provincial Way No.78 have been claimed by mass media. Therefore, in order to clarify the correction of the subsidence problems, the best strategy is planning and implementation of the monitoring plan. It means that monitor the settlement of the subsoil nearby the cross section along the THSR line and the Provincial Way No.78 in long term by using Multi-level Compaction Monitoring Well. In the same time, the soil settlements between the beneath of the THSR’s pier and the embankment of the Provincial Way No.78 can be compared and these problem’s correlations can be identified. In this research, Leveling, Global Positioning System (GPS) and Multi-level Compaction Monitoring Well are be used to monitor the subsidence situation from several different aspects of the sky, ground surface and underground. Their advantages are be captured and applied in these different methods. This monitoring plan began and the information on past and update were collected and analyzed since March 2011. The results of this study show that the settlement of the THSR’s bridge pier close to the Provincial Way No.78 is higher than others. The most settlement is 69.245cm since THSR started operating till March 2011. The settlement is about 14.245cm by reducing regional settlement 55cm when the loading from both the THSR’s bridge pier and the embankment of the Provincial Way No.78. The settlement of the embankment is 6.667cm is included. Meanwhile, the settlement at the Well depth 300m is about 47.5 where located away from the center of the cross section along the THSR line and the Provincial Way No.78 about 262.09m. Besides, the total settlement is 43.8cm (about 92.2%) where the Well depth from 100m to the bottom induced. However, the settlement of the embankment is 6.667cm which is smaller than the depth layer induced. So that, it can be proved that the influence line is reduced and extended to the outside and depth progressively which is induced by the embankment. This is totally different from the monitoring result from the Well which occurred the larger settlement with deeper location. This conclusion can be summarized that there is no strong relationship between the soil compression and ground surface loading. The main cause of the embankment subsidence was induced by deep water pumping and water level changed.