关键词: 港口工程, 复合桩, 竖向加载, 水平加载, 承载特性, 现场试验

Abstract: In order to study the bearing characteristics of the large diameter tubular pile-steel pipe composite pile foundation, relying on the construction of the pile foundation of the second phase of the wharf in the Zhuangyuanao port area of Wenzhou Port, the engineering piles S1 and S2 were selected as the test piles to carry out the vertical static load and horizontal static load test respectively. The vertical static load section strain value ε and pile top displacement Y, pile top rotation angle θ under horizontal static load were measured. The pile axial force Qaxial, pile tip resistance Qpu and pile side friction Qs under vertical static load as well as the mud displacement Y0 and angle θ0 at the mud surface under horizontal load were calculated. The variation law of pile top displacement S changing with horizontal load Q in the process of vertical static load and horizontal static load was analyzed, as well as the variation law of vertical stiffness coefficient K, axial force value Qaxial and pile side resistance Qs at different pile elevation were analyzed. The research shows that the Q-S curve of pile foundation shows slow deformation under vertical static load test; the vertical bearing capacity of test pile S1 and S2 is not less than 10,500 kN, which can well meet the requirements of engineering design; the lateral friction resistance of the pile gradually develops with the increase of embedded depth z of pile body, and its distribution form is “hump-shaped”; under the maximum vertical load Qmax, the test pile S1 and S2 pile tip load ratios are 9.55% and 8.45% respectively, which represents as friction pile; under the horizontal load H, the horizontal bearing capacity of test pile S1 and S2 meets the design requirements; and the maximum bending moment of S1 and S2 is 820 kN·m and 1,038 kN·m respectively, both of which occur at about 3.0 m below the mud surface. It is proved that the large diameter tubular pile-steel pipe composite pile foundation can meet the engineering requirements of the project.

Key words: port engineering, composite pile, vertical loading, horizontal loading, bearing properties, field test