| In constructions of highways and railways,rigid piles,such as pre-stressed highstrength concrete(PHC)piles,are prevailing to decline post-construction settlements.However,destabilization occurs.The methods proposed in codes are based on limit equilibrium method.Bending failures of rigid piles in soft ground under embankments are misunderstood and relations between bending moments and displacement of the soft ground.In MATLAB,based on Mobilizable Strength Design(MSD),interaction of soil and pile are calculated is introduced to predict the deformation of the ground and load properties of the piles.The method was verified by centrifuge tests in previous and this paper.In addition,piles with various locations,stiffnesses,and conditions of fixity are discussed.Finally,horizontal and vertical properties are combined,and their effects on stability of grounds under embankments are studied.In the horizontal direction,bending moments are larger of piles at the center of the displacement field,with larger stiffness,and superior condition of fixity,and piles prefer to fail at the interface of soft and hard layers of the soil.On contrary,others are inclined to fail at the boundary of the displacement field and center in the fan zone.For floating piles,toppling is common.Interaction of multi-row of piles is slight and can be neglected.In the vertical direction,axial load on the top of the piles can be ignored in practice engineering.The postion and value of maximum axial force on piles,which are influenced by negative friction,is decied by the position of them.And the value becomes the vertex near the middle of field’s center and boundary.In the constructions of embankments,the rigid piles fail progressively,and second failure will occur.The piles at the center of the displacement field may fail under a low embankment loads,while those away from center will not fail even the embankment is high.The displacement and stability of the soft ground are decided by the states of the rigid piles. |
