Analysis Of Mechanism Of Pile-Soil Interaction And Performance Of Passive Piles

The issue of pile-soil interaction is the research hotspot and difficult subject in pile foundation engineering for recently several years. The majority of piles are designed to support "active" loadings, that is to say, loads from upper structure are directly transferred to the pile foundation by the cap. However, there are many cases in which the piles have to withstand "passive" loading, i.e. loads in the piles are often induced by the movement of soils past the piles vertically and/or horizontally. Examples include consolidation of clay; swelling or shrinking of an expansive clay; tunneling; excavation; cavity development; slope movement. These externally-imposed soil movements will lead to additional forces and stresses into pile foundations. Therefore, it is very important to reasonably assess these forces and the corresponding effects on the bearing and deformation performance of pile foundation.This paper analyzes the pile-soil interaction adjacent to superficial surcharge, the pile is modeled simple elastic foundation beam, soil to be elastic-plastic deformation body. Based on the compatibility condition of deformation of piles and surrounding soils, the expression formulation of lateral earth pressure on piles is presented. And then the partial differential equation for governing deflection of pile is established and is numerically solved by combining non-linear p-y relationship curve of pile and finite difference procedure. The author encodes the corresponding program. Through an example analysis, the reasonability and applicability of the proposed method are verified. Therefore this simplified method can be useful in evaluating the interaction behavior of pile and soils under passive state. Moreover, the author studies the complicated factors that affect the deformation of pile-soil system. The result indicates that the lateral displacement of the pile can be related to the pile bending stiffness and horizontal pile-soil interaction stresses, the lateral displacement of the corresponding soil is related to the soil stiffness, the pile-soil interaction stresses, and the free-field horizontal soil movements, and so on. According to the comprehensive analyses, the author draws some significant conclusions.