受轴力作用的桩基在水平振动时的抗力

该文在现有模型的基础上,把桩基和土看成一个整体——嵌入桩基的粘弹性半空间.其中,桩基被看成是等圆截面的粘弹性Euler梁,并受到轴力的作用;同时将土看成由两种粘弹性介质的圆柱体组成,接近桩周的内层土域视为非线性粘弹性圆柱体,远离桩周的外层土域视为线性粘弹性圆柱体.在空间柱坐标系中建立了相应的边值问题,利用分离变量法得到了形式闭合解,从而可求得各阶波形下的土抗以及桩基在各种端部条件下的刚度.考查了参数对桩基刚度的影响,特别是轴力对桩基刚度的影响.结果表明,受轴力作用的桩基可能丧失其承载能力.因此,研究桩基的力学行为时,必须考察轴力的影响.

Resistance of Pile against Horizontal Vibration under Axial Force

On the basis of an existing model, a pile and soil are regarded as an integrated system, that is, a pile embedded in a visco-elastic half-space. Assume that the pile is a visco-elastic Euler beam with a circular cross-section on which an axial force is applied. The soil is composed of two parts: an outer infinite linear visco-elastic zone and an inner nonlinear visco-elastic zone, both being cylindrical. In a cylindrical coordinate system, a corresponding boundary value problem is established and the solution is obtained using separation of variables. Hence, dimensionless horizontal resistance and stiffness of the pile can be obtained under the given end conditions. The effects of parameters, axial force in particular, on resistance and stiffness are studied in detail. Numerical results show that a pile with an applied axial force may possibly lose its stability. Therefore the effect of axial forces must be taken into consideration when studying the mechanical behavior of piles.