Application Of Post Grouting Technology In Super-long Bored Pile

According to the geological prospecting report and piles design file, the load eigenvalue and vertical ultimate bearing capacity of single bored pile are calculated based on the foundation pile project in Taiyuan Guohai Plaza. The principle of acoustic transmission method, in-situ test and pile internal force test for bored pile are discussed, and then some related tests are conducted.According to the analysis of test data from acoustic transmission method, the level of pile concrete quality are determined.The vertical ultimate bearing capacity of single pile is given based on the data of applied load at all levels, maximum applied load and pile top settlement through in-situ test.The data collected from the reinforcement stress gauge during testing process are analyzed. The pile internal force values are calculated and then the corresponding curves are plotted, based on which, the pile side resistance and end resistance values of each section applied by the maximum load are obtained, to calculate the vertical compressive resistance eigenvalue and capacity value of single bored pile.From the comparison between the theoretical calculation and in-situ test results, the increase of bored pile bearing capacity through posting grouting is calculated and the mechanism of posting grouting method is analyzed. Results show that posting grouting can shorten the length of pile effectively, reduce the construction difficulty, shorten the construction period and save construction cost, as well as to provide experience for the posting grouting construction of super-long bored pile in Taiyuan.