This research collected water table or piezometer pressure monitoring data from several large-scale deep excavation projects of the Taipei Rapid Transit System. The available hydrogeological parameters of Jingmei gravel formation and the geotechnical characteristics of Songshan formation were also compiled systematically. The valueable information obtained can be applied in predicting the regional drawdown of piezometer pressure during large-scale dewatering caused by groundwater pumping in the Jingmei gravel aquifer. Further application can be used to estimate the settlement of each local site due to the drawdown. Experience acquired from the study show that the amount of settlement is mainly ralated to the drawdown of pore-water pressure for each formation. The settlement was also related with the deformation characteristics of Jingmei gravel formation and the sandy or clayey Songshan sub-formations.

Furthermore, in order to assess the validity and the accuracy in groundwater drawdown simulation and ground settlement prediction, various dimensional analyses for several actural cases were also carried out. These results can help to establish a regional hydrogeologic conceptual model and standard procedures that would make dewatering analysis more accurate and effective.

Finally, the main factors that influence and limit model application for large-scale dewatering caused by pumping groundwater in the Jingmei gravel aquifer were suggested.