A Study On The Monitoring Safety Of Great-axial-load-pile Underpinning Technology

The underpinning of high-load-pile foundation under the complex geological conditions, may deal with many problems of structure, subsoil, and underground water. Many underpinning engineering would be meet as new tunnel of metro are being built in many cities in our country such as Beijing, Shanghai, Guangzhou, Shenzhen. So special research is necessary and in urgent needed.Pile foundation project of Department Store Mansion is one of the key construction sub-project of Shenzhen Metro. As a case study, methods of theoretical analysis, model testing and Situ testing have been applied to study on the safety problem in underpinning engineering of high-loaded pile foundation.Based on the above study, an advanced reliable monitor system was established, meanwhile a series of control limitations of active-underpinning were put forward.During the construction of underpinning structure, active-underpinning and excavation of tunnel, the displacement and stress of Department Store Mansion and underpinning beams are all below the control limitations. The active underpinning in Situ of Department Store Mansion is succeeded as the research prediction.How to improve the stress release method and how to determine the bearing resistance are discussed at the end.