The Analysis Of Lateral Action Beteen Soft Soils And Piles

Piles under the bottom of a pit are always subject to deflection due to excavation-induced soil movement on soft foundation. On the other hand, piles undergo destroy by soil lateral movement because of soil consolidation, plastic yielding, and flowing. These are all decrease vertical bearing capacity of piles and its use. Now the similar engineering accidents are prevalent on the areas of soft soil area.The interaction of piles and soil lateral movement in deep excavation on soft ground belongs to the research scope of passive piles. It is very difficult to study this kind interaction because earth pressure on piles by soil movement can't be evaluated, and assessment of pile behavior, destroy degree and residual bearing capacity are even impossible. But these are needed to solved urgently for correct analysis of piling engineering accidents and suitable improvement methods.First literature of results and progress on close subjects at home and aboard is reviewed. Then numerical simulation is applied to study several problems as follows.(1) Mechanism of interaction of pile and soil movement is discovered at the point of soil arching effect, and relationship between earth pressure and soil properties or piles arrangement are illustrated. The deficiency of Tomio Ito earth pressure formula cited widely is pointed out according to the relationship between earth pressure and soil properties, and mechanism of pile-groups interaction are interpreted according to soil arching effect.Few researches have been studied on the mechanism and behavior of soil arching effects in passive piles, especially the comparison when soil parameters changed. Plane FEA is applied to study these problems above, and four key factors of soil arching effects, such as its shape, the vertical displacement contour, plastic or tensile area of soil between piles and remained stress behind piles are investigated by changing cohesion, internal friction angle, elastic modulus, poisson ratio, dilatancy angle, interface conditions respectively. It is found that, the yield mechanism of cohesive and cohesionless soils around piles are different when forming the soil...