Design of socketed piles for 438 m-high Wuhan Center Building

Wuhan Center Building, the highest building under construction in Central China, is 438 meters high with structure of 88 ground layers and 4 underground layers and an embedded foundation depth of 20 meters. Mild mud rock lies 60 meters below the basement. Pile foundation design is difficult because the estimated bearing capacity of a single pile is not less than 2000 kN due to the high structure and no available engineering experience. Post grouting into the end and side of test piles with a diameter of 1000 millimeters and a length of about 65 meters is applied to field full scale tests in order to compare situations of various rock insertion depths. Large tonnage load tests and measurements of axial force and deformation are carried out so that the status of load bearing and deformation capacity of socketed piles is obtained and the basis for pile foundation design is provided. Based on the idea of effect of ground, foundation and structure synergistic, rational layout of pile groups and rock insertion depth are obtained. In accordance with comparison and selection of different construction equipments and technologies, the rotary drilling machine, special bucket mud and slag cleaning technology are adopted. This can resolve pore-creating challenge for deep sand and mild rock layers and enormously enhance work efficiency and guarantee quality.