对桩基承载力计算的影响因素的研究

本文应用波动方程计算程序,逐个改变输入参数,对单桩的承载力进行了大量的计算,分析了各个参数对桩承载力的影响。分析表明,所有输入参数可分为两大类:桩-土系统的固有参数和桩-锤系统的辅助参数。固有参数包括土的Q值、粘性阻尼系数J。和J,桩的弹模、截面积和桩长等等,它们的值决定桩的承载力;辅助参数包括锤重、落高、帽垫、桩垫和桩帽的弹簧常数、锤击效率等,它们的值的改变将表观上影响R-S曲线或R,-N曲线,但不改变桩的实际承载能力。

A Research for the Influential Factors on the Pile Bearing Capacity Computation

In this paper, a great quantity of computation on the pile bearing capacity are made by using the wave equation computer program with successively varying input parameters. The effect of each parameter on the pile bearing is analysed. It is shown that all the parameters can be classified into two groups: the intrinsic parameters held by the pile-soil system and the auxiliary parameters held by the pile-hammer system. The intrinsic parameters, including the quake of soil, the visco damping coefficient, the elastic moduli of pile material, the cross section area and the length of the pile, play the dominant role in the determination of the pile bearing capacity. The auxiliary parameters, including the hammer weight, the hammer fall, the spring constant of the cap-block, the coefficient of restitution of cap-block and pile-cushion, and the efficiency of the hammer, etc., only influence the curves Ru = ｆ(S) or Ru =ｆ(N) but not change the value of the actual bearing capacity of the pile. From the analysis it is also indicated in the paper that the quake value of the soil, besides the intrinsic parameters held by the pile itself, is the mast influential factor on the pile bearing capacity.