Stability Analysis On The Composite Foundation Reinforced By Rigid Piles Under Flexible Foundation

Aimed at the stability analysis of rigid pile composite ground under flexible foundation is not perfect:first, this paper studyed the composite foundation by three-dimensional finite element model, stress mechanism and failure mode of piles at different locations was studied as the loading and failure of the embankment; on the basis of the achievements of home and abroad; adaptability of several common instability criterion in rigid pile composite ground under flexible foundation was discussed by strength reduction finite element method, meanwhile, analyzed the displacement vector, slip surface shape and location failure as the instability occurring; on the Basis of the results by conventional finite element and strength reduction finite element method, the rationalization partition of Pile-Reinforced embankment was given by different locations and mechanism of skid resistance; studied the effects of height of earth bank, internal friction angle of soil between piles, pile replacement ratio、cohesion of soil between piles、embed depth of pile、 stiffness of cushion to stability factor of embankment with orthogonal analysis; adaptability of traditional stability analysis method、equivalent shear strength method、BS 8006 method、 numerical simulation method in the stability analysis of rigid pile composite ground under flexible foundation; finally, based on the Basic Principle of limit equilibrium method, simplified method was given for stability analysis which accord with the force condition of rigid pile composite ground under flexible foundation.The results showed:strength reduction finite element method has good applicability in the stability analysis of rigid pile composite ground under flexible foundation; take the abruptness of the displacement at toe and top of slope as instability criterion is relatively reliable; piles at different locations provide different anti-slid contributions; on the basis of different locations and failure modes, piles can be divided into compression、bending and tensile class; the effects to stability factor of embankment decreased systematically from height of earth bank to stiffness of cushion, in addition, there are no interactions between influence factors; the simplified method of stability analysis for rigid pile composite ground under flexible foundation given by this paper which really reflect the force condition of embankment has good adaptability.