Research on the Construction Technique of Super-Large Diameter Rock-Socketed Piles in Karst Areas: Fid-Bau Portal

Research on the Construction Technique of Super-Large Diameter Rock-Socketed Piles in Karst Areas

Xing, Hao Feng / Meng, Ming Hui / Long, Wan Xue / Ye, Guan Bao / He, Wen Yong

It is difficult for the large diameter pile to bore the hole and ensure its quality under the complicated geological condition in karst areas. In order to get the feasible construction method, the construction technique of super-large diameter rock-socketed piles in karst areas was explored in this paper on the basis of Hezhang Super Maior Bridge project in Guizhou province. The adaptability of the construction plan at this site was expounded firstly; and then the technologies for dealing with the problems of buried hammer, inclined hole, slurry leakage, which often occur during the process of boring pile hole under complicated geological conditions, were deeply researched. The research results show that it is effective to use the slurry with the relative density of 1.30 to 1.35 to prevent the pebble soil layer from collapsing, to prevent the pile hole from inclining by backfilling rubble in tilted stratum, to treat the slurry leakage problem by backfilling rubble, clay soil and bagged cement; and to handle the hammer stuck through the skills of underwater blasting, salvaging with pothook and light pounding with small hammer. It is proved that the method of light pounding with small hammer is preferable to handle the stuck hammer occured in backfill hole. The study provides the theoretical guidance and reference for similar projects.