Study on Design Method of Vertical Bearing Capacity of Rock-Socketed Piles Based on Reliability

The traditional vertical bearing capacity design method of rock-socketed piles uses the constant safety factor K to assess the reliability of pile foundations, and this method leads to the high cost or the insufficient safety reserve of some pile foundations. The Bayesian optimization estimation was used to process the complete data of 144 rock-socketed piles, 65 sets of skin resistance data and 31 sets of end resistance data in rock-socketed segment. The analysis of the probability limit state design method was carried out for the five partial resistance coefficients: the whole pile, the skin resistance of soil section, the resistance of rock section, the skin resistance of the rock section and the end resistance of the rock section. The relationship between the partial coefficients, embedment ratio and uniaxial saturation compressive strength of rock was established, and the suggested partial coefficients was proposed. Finally, the partial coefficients were introduced into the calculation formula of the vertical bearing capacity of rock-socketed piles in the Code for Design of Ground and Foundation of Highway Bridge and Culvert. This formula can provide reference for further revision and improvement of existing normative practices.