钻孔灌注桩压浆后承载性能的可靠度分析

钻孔灌注桩在压浆后的承载特性得到明显改善，离散程度明显降低，但目前对压浆后钻孔灌注桩的可靠度还缺乏系统研究。收集了122根未压浆的钻孔灌注桩和147根压浆后的钻孔灌注桩静载试验资料，结合可靠度分析方法中的确定性和不确定性分析方法，利用近似概率法的基于一次二阶矩法的验算点法（简称JC法）和Monte Carlo法对钻孔灌注桩压浆前和压浆后的可靠度指标进行了对比分析。结果表明：压浆后桩的可靠度指标有很大幅度提高，压浆可减少持力层对可靠度的影响，同时后压浆桩的可靠度有随桩径增大而提高的趋势，且不同荷载效应比值下可靠度随桩径变化的趋势趋于一致。

Reliability analysis of bearing capacity of post-grouted bored piles

The bearing capacity of bored piles is significantly improved and the dispersion of bearing capacity is reduced obviously by employing the method of grouting. However, the reliability of post-grouted bored piles is still lack of systematic research yet. In this study, the static load test data of 122 non-grouted bored piles and 147 post-grouted bored piles are collected. Then, combined with the certainty and uncertainty analysis methods in reliability analysis method, the approximate probability method based on the first-order second-moment method (JC method) and Monte Carlo method is employed to analyze the reliability indexes of these forementioned post-grouted bored piles and non-grouted ones.. The results indicate that the reliability index of post-grouting bored piles have been greatly improved compared to the non-grouting ones and the bearing stratum has less influence on the reliability of post-grouted bored piles than the reliability of non-grouted bored piles. Moreover, the reliability of post-grouted bored piles tends to increase with the increase of pile diameter and this trend between reliability and diameter remains consistent even under different load compositions.