In-situ Monitoring of Side Friction of Drilled Piles by Different Loading Methods

Side frictions of three groups of drilled piles under different loading methods in Xinwan interchange of Qianjiang Passageway and Connecting Project were monitored. Group 1 was loaded by static loading test method. The other two groups were loaded by dead load of superstructures, which were constructed using segmental hanging basket method and overall support cast-in-place method respectively. Axial forces and Side friction in all the piles increased gradually during the load-adding procedure. Group 1 was loaded two months after the finish of pile foundation construction, while group 3 started bearing the action of superstructure dead load six months after the finish of pile foundation construction. Piles in Group 1 and Group 3 have different repose time. Side frictions monitored from piles in Group 3, which have longer repose time, were larger than those in Group 1 under the same load. Side frictions monitored from piles in Group 2, which have longer off-time between two loading stage, were larger than those in Group 1 under the same load.