Grouting and Dewatering in Balancing Settlement of a Building

A case study using grouting and dewatering system to protect a residential building during an adjacent deep excavation is presented in this paper. The building was a 73-year old masonry structure with two additional stories added to its original designed four stories height. The building was located 5 m away from a 15 m deep excavation. The project was located in downtown Shanghai, China. Grouting was injected between excavation and the building to compensate for ground loss and stress relief to reduce the building’s settlement. Dewatering was applied at the far end to increase the settlements and limit the differential settlement. This project was the first successful case using dewatering to protect a building in such a low permeability Shanghai clay. The results demonstrated that dewatering and grouting methods were an effective way of protecting buildings near deep excavations