Investigate the post-grouting bearing property of drilled piles in heavily weathered mudstone strata based on the O-cell test method

Abstract The study focuses on analyzing the bearing capacity of six cast-in-place drilled piles located in three distinct portions of the urban square at Ronghe East Station in Nanning was evaluated through static load testing using the Osterberg cell (O-cell) method, and the bearing deformation characteristics of post-grouting piles in heavily weathered mudstone stratum were analyzed. By fitting the resistance and relative displacement curves at the pile end and side, a load-settlement calculation method for post-grouting piles in a heavily weathered mudstone stratum was established by adopting the hyperbolic load transfer model, which has the tip hardening and the side softening. The accuracy of the method was verified through actual engineering test pile modeling and changed post-grouting piles' diameter and length to further examine their bearing properties. The bearing capacity exhibits a progressive increase with an increase in either the length or diameter of the pile. However, an effective length exists when the pile length is increased to increase the bearing capacity. The use of combined grouting technology can achieve a significant increase in bearing capacity, up to approximately 1.3 times, which can realize the economy and high efficiency of improving the bearing performance of pile foundations.