Dewatering experiences in deep excavation – Case studies in Vietnam

Abstract

Groundwater table could be a significant problem during the excavation of a basement. Water through seepage forces does not only interrupt the construction work but also reduce soil strength that leads to instability of support systems. Therefore, groundwater control methods (or dewatering) before or during basement work are indispensable. Many experts have proposed both analytical and numerical analyses for simulation of the dewatering process. However, in reality, the calculation and arrangement of dewatering wells are often uncertain due to a lack of geology investigation and seasonal changes of the groundwater table. To facilitate the construction work, a quick solution needs to be proposed. In this paper, the experienced mitigation methods during basement construction are presented through case studies. In detail, deep excavation with various support systems and complex geotechnical and hydrogeological conditions have been chosen. Differences between dewatering systems in design and at actual site conditions are also shown. Thereby, an optimal design would be obtained in the future.