Abstract: 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.

Key words: bored piles, post grouting, reliability, JC method, Monte Carlo method