桩径对Mindlin附加应力系数的影响分析

Research on pile radius effect to the coefficient of Mindlin additive stress

基于Mindlin理论关于点荷载附加应力系数的解析解答,研究不同土体泊松比、桩长条件下桩径对Mindlin附加应力系数的影响规律,确定不同偏差标准下必须考虑桩径影响的最小范围,并给出需考虑桩径影响最小范围的拟合公式。研究结果表明:土体泊松比对Mindlin附加应力系数总体影响较小,统一采用0.35土体泊松比引起附加应力计算偏差一般不超过5%;Midlin附加应力计算中,必须考虑桩径影响的最小范围主要与桩径相关,且随桩长的增加而增大;分别采用1%和5%误差标准时,必须考虑桩径影响的最小范围分别为桩径的13.6倍和6.41倍。

Based on the analytical solution of Mindlin theory for the additive stress calculation induced by pointloading, relationship between pile radius and the Mindlin additive stress coefficient was discussed in details withdifferent poisson ratio and the pile length. Subsequently, the minimum influence range of pile radius under differenterror standard was determined, and the fitting equation of influence range was also obtained accordingly. Researchresults in this study indicated that, influences of soil poisson ratio to the additive stress was at a very lowlevel, and the greatest error was only about 5% if applied the poisson ratio value with 0.35 in common. Duringthe calculation of Mindlin additive stress coefficient, the minimum influence range of pile radius was mainly determinedby pile radius, and it would keep increasing with pile length. Moreover, if the error standard were 1%and 5% respectively, it would be not necessary to consider the pile radius influences as the distance to the loadcenter had exceed 13.6 r0 and 6.41 r0.