The detective and remedial methods for defective bored piles in Hong Kong

Abstract

The construction of bored piles serves as a prevalent foundation technique in Hong Kong. Nevertheless, the integrity of these piles may be compromised due to a multitude of defects including cracks, cavities, and inadequate concrete encasement. Such imperfections can impart the safety and structural integrity of the bored piles. Consequently, the identification and rectification of these defects is crucial in guaranteeing the enduring stability of the substructure. This paper presents a comprehensive review of the detective and remedial methods for defective bored piles in Hong Kong. Various techniques used to identify and diagnose defects in bored piles are discussed, including Crosshole Sonic Echo Test, Sonic Logging Test, and Coring Test. The remedial methods for repairing and strengthening defective piles are also discussed, including high-pressure water cutting and cement grouting or jet grouting, installment of additional steel H-sections with backfilling of grout. Four real construction sites in Hong Kong are analyzed based on their Coring, Koden, Sonic test results, some of the remedial work for defective bored piles are discussed as well. The findings of this paper can provide valuable insights for engineers, contractors, and stakeholders involved in the construction and maintenance of bored pile foundation systems in Hong Kong.