基于高阶矩法的单桩承载力可靠度研究

Study on reliability of bearing capacity of single pile based on higher order moment method

建立单桩承载力的功能函数,并用此功能函数发展了基于高阶矩法的单桩承载力可靠度分析的方法。算例为四根不同长径比的桩基。分析结果表明与蒙特卡洛法(MCS)和一次二阶矩法(FOSM)相比,采用高阶矩法进行单桩承载力可靠度分析能够在保证计算精度的前提下提高计算效率,同时也能够得到各桩基承载力功能函数分布中的前三阶统计矩(均值,方差,偏度);再利用分布参数为前三阶统计矩的三参数对数正态分布来描述算例中各桩承载力功能函数的分布特性。该方法为桩基承载力可靠度的研究提供了一条有效的途径。

The function of bearing capacity of single pile is established,and the method of reliability analysis of bearing capacity of single pile based on higher-order moment method is developed.Four piles with different length diameter ratio are taken as examples.The analysis results show that:compared with the Monte Carlo method(MCS)and the first-order second moment method(FOSM),the higher-order moment method can improve the calculation efficiency on the premise of ensuring the calculation accuracy,and also can obtain the first three order statistical moments(mean,variance,skewness)in the distribution of the bearing capacity function of each pile foundation;and the lognormal distribution of three parameters with the first three statistical moments is used to describe the distribution characteristics of the bearing capacity function of each pile in the example.This method provides an effective way to study the reliability of bearing capacity of pile foundation.