Self-balanced method for large-diameter bored piles of Hong Kong-Zhuhai-Macao Bridge

Taking Hong Kong-Zhuhai-Macao Bridge as an engineering example, two bored piles are regarded as the test piles. The parameters are obtained based on self-balanced load test piles. The construction process of deep foundation of the sea is studied. The results verify that the problem of constructing offshore pile foundation with high requirements for equipment performance drilling is solved by using the four-wing drag bit in the cover layer and ball hob drill head in the rock layer. In the actual construction of the bore holes, for pile No. SZ5, seawater + undisturbed soil slurry are used, and for pile No. SZ6, the freshwater + undisturbed soil slurry are used. High-quality mud is developed to ensure the quality of the two bored piles. Through the analysis of the static load test data, comprehensive consideration of various factors, related design parameters are obtained so as to improve the pile foundation design. The results may provide reference for applying large-diameter bored piles.