下卧碎石层对静压管桩挤土效应的影响

利用通用有限元软件ABAQUS分析软土地基下卧碎石层对静压管桩挤土效应和承载力的影响,并探讨管桩不同贯入深度时地表竖向隆起、地基土体水平位移、桩周土体和桩身应力的变化规律.结果表明:静压管桩施工导致桩周附近地表隆起,随着离开桩周的距离增大,地表隆起效应迅速减弱;静压管桩使桩周土体产生显著的水平挤压效应,静压管桩施工至下卧碎石层时,碎石区域中的位移效应明显小于桩周土体为软土时的位移效应;以碎石层为持力层,可显著提高管桩的承载力.

Influence of Underlying Crushed Rock Layer on Compacting Effect of Jacked Pipe Pile

Influence of underlying crushed rock on compacting effects and bearing capacity of jacked pipe pile was analyzed by general finite element method ABAQUS. Change rules of ground upwarping,ground horizontal displacement,compressive stress of pipe pile and foundation around it were discussed under the condition of different penetration depth of pile. Analytical results show that installation of jacked pipe pile will result in ground upwarping , influential range of ground upwarping is within 1.5D distance of pile side, and as the distance to the pile side is increased, ground upwarping effect is weakened quickly. Installation of jacked pile will cause remarkable horizontal soil-compacting effect around it. When pipe pile is penetrated into underlying crushed rock, deformation effect of it around pipe pile is obviously weaker than that of soft foundation because stiffness of crushed rock is larger than that of soft foundation. Crushed rock layer is significantly meaningful to the increase of bearing capacity of pile due to larger stiffness and higher strength of it, which is as bearing layer.