Influence Of Excavation On Stability Of Pile Foundation In Soft Clay

Geotechnical engineers are often require to either assess the lateral response of existing piles caused by adjacent settling approach embankment, pile driving operations, excavation operations, tunneling operations, moving slopes or landslides, and so on, or to design piles to stabilize unstable slopes or potential landslides. Piles may become of no use, which are referenced to passive piles and frequently subjected to the soil movements due to surcharge loads inducing bending moments and deflections in the piles in many engineering practice cases, such as dock, bridge abutments, and industry workshop. And this may lead to their superstructure distress or failure. The problem of piles subjected to lateral soil movements has become a subject of considerable research work. However, great uncertainties still remain in relation to the theoretical solutions for estimation the piles response. So it is significant to study the behavior of passive piles. In this research report, firstly research background and a review is presented on the existing available literature including subjects of soil pressure on passive piles, the styles of soil movements, the calculation and analysis methods, and report the mechnical behavior of the soil include the soft soil creep. Secondary, a geotechnical Finite element method is also used to simulate the behavior of piles subject to the soil movements due to surcharge loads under the various influencing factors such as pile space, soil properties, and so on. Influence of excavation on pile foundation stability in one engineering of Tianjin Economy Developing Zone was analyzed by using ABAQUS program. Failure cases repeatedly take place in soft clay foundation in Tianjin area. The pile foundation in soft soil often is affected by the side excavation of foundation slot, even lead to the pile foundation to tilt and break. This paper establishes a model to simulate these phenomena by finding out the deformation, stress and the deflection of the pile foundation difference before and after excavation. The results demonstrate that the excavation can seriously influent the deformation, the rotation and the displacement of the pile foundation, the stability of the whole pile foundation, integrate with the mechanics feature to anatomy the stability, destroy condition. At last summarize the present theory, and put forward the future research.