Design and Application of a Monitoring System for a Deep Railway Foundation Pit Project

With the development of urban underground space in China, foundation pits have followed a trend toward larger area and greater depth. To ensure the safe excavation of foundation pits, it is necessary to monitor their deformation and the internal force of supporting structures and then use assessments of pit and building stability to guide construction. This paper introduces the design and development of a safety monitoring and warning system for deep foundation pits and adjacent buildings. The monitoring information management system uses Visual Studio 2013 as its development platform and adopts the SQL and C# programming languages to realize its powerful data management and visualization functions. By combined consideration of the monitoring information and the layout of the measuring points, monitoring data on the deformation of the deep foundation pit, ground subsidence and deformation of adjacent buildings are analyzed comprehensively. The results show that: first, the horizontal deformation of the side wall of the rock foundation pit achieves its peak value when 50% of the excavation has been completed and tends to change steadily after the completion of anchor construction. Second, the ground surface around the Fengjing area exhibits upward vertical deformation closest to the side wall of the foundation pit, and then downward deformation at greater distances from it. The ground surface relatively far from the side wall exhibits settlement. Third, the internal force of a plate-ribbed anchor retaining wall in the Fengjing area becomes greater at greater depths. Finally, the excavation of a rock foundation pit has relatively little influence on the inclination of adjacent buildings.