Application and field tests of cap-pile combined foundation with reversed construction

To further study the applicability of the cap-pile combined foundation in bridge engineering, the application of the cap-pile combined foundation with reversed construction in bridges is carried out. For water and dry construction environments, the structural design and construction technology of the closing net template and steel tube with shear connectors of pile cap prepared hole are proposed, and the reliability of the technological scheme is verified through 12 groups of model tests. The load bearing behavior of the cap-pile combined foundation with reversed construction is revealed by the field tests. The results indicate that the combined foundation, which first constructs piles and the cap with prepared hole, and then make connection between piles and pile cap to shear upper load together after bent cap finished, can make the subsoil of pile cap bear the upper load and take full advantage of the bearing capacity of shallow soil. The increments of foundation settlement and soil pressure significantly decrease after pile connection, and then the increasing upper load is mainly borne by the piles, which can effectively control the settlement of bridges.