Cause investigation of damages in existing building adjacent to foundation pit in construction

•Damaging in adjacent building during constructing foundation pit is investigated.•The principal causes of damaging in adjacent building are clarified.•Both soil excavation and dewatering in foundation pit construction influence stratum settlement.•Dewatering has much influence for sludge with main constitution of fine sand.

This paper presents a case study of investigating damages in existing building adjacent to foundation pit in construction, in which the settlement influence of adjacent building induced by constructing foundation pit is demonstrated by means of field observation, numerical analysis and experimental investigation. This study focuses on the principal cause inducing these damages in the existing building. This work demonstrates that the stratum settlement of the existing building during excavating foundation pit are significantly influenced by not only construction task of excavating soils but also that of dewatering soil mass in constructing foundation pit, since the principal constitution of fine sand and medium sand in the sludge can be easily run off with stratum loss during the dewatering task, and the hydraulic connection between the inside and outside of the foundation pit thus can't cut off using underground continuous wall, which can probably produce structural damage of soil mass with stratum settlement.