Abstract: According to the limit state of geotechnical structures at a specific site under normal conditions of use, the reliability index of various structures is calculated by geometric reliability method that developed in recent years. At the same site, considering the discreteness of load-displacement curves of bored piles, anti-floating anchors and single CFG piles, the regression parameters of these curves show differences and can be regarded as random variables. The correlation and joint distribution characteristics of the site-specific regression parameters are discussed. Based on the joint divergence probability density contour (PDC) of these regression parameters, which means the random variables just reach the critical state of limit bearing capacity, the reliability index of geotechnical structures is calculated by the geometric reliability algorithm in the original space of random variables. The feasibility of geometric reliability algorithm is verified by comparing the geometric reliability index with the results calculated by conventional first-order reliability method. The results show that the geometric reliability evaluation model is simple to implement and can be easily accepted by engineers and technicians.

Key words: discreteness, probability density, goodness-of-fit, bearing capacity, geometric reliability