Applied Research on Underpinning Technology for Protection of Structure Closed to Deep Excavation

Building structures are insecurity when it is closed to foundation pit, which likely to collapse or produce large deformation due to design or construction faults. Dead loads of structures applied on the top of pit slope and add the probability of circular sliding of slope. Underpinning technology can transfer loads to the deeper soil layer and deformation had been restrained effectively. With the development of foundation underpinning technique, more and more mini-pile should be drilled through the foundation inner or outer buildings structures. When the structures protected by underpinning method, the foundation pit supporting project can be designed more easily and flexibly. By one engineering example, underpinning technology and foundation pit supporting technology are combined and applied to protect the stability of structures near the pit. Using the united method, the loads of structures are transferred vertical and pressure on the top is reduced highly, active earth pressure is lower at the same time, so that the excavation stability can be achieved more easily. The engineering examples provide better technical references for similar projects.