海上复杂地质条件下大直径钢管桩时效性试验研究

通过对3根海上复杂地质条件下的大直径钢管桩采取高应变初打与不同休止时间复打相结合的试验方法,得到不同休止时间钢管桩承载力、侧阻力及端阻力大小,以此对不同桩侧土及持力层对钢管桩时效性的影响进行了研究。研究结果表明:1)钢管桩承载力时效性现象明显,且随时间增长迅速; 2)钢管桩侧阻力的恢复系数远大于端阻力; 3)桩侧黏性土强度的恢复是钢管桩侧阻力增加的主要原因; 4)砂土层虽提供的侧阻力较大,但其对侧阻力增长的贡献不如黏性土; 5)持力层越硬,端阻力与承载力的恢复性越差。

Experimental study on time effect of large diameter steel pipe piles under complex geological conditions at sea

Three offshore large diameter steel pipe piles were tested by high strain dynamic technology for the first strike and the restrike was done in different rest periods. And the steel pipe pile??s bearing capacity side resistance and end resistance at different rest times were obtained. Therefore, the effect of different pile side soil and bearing layer on the time effect of steel pipe piles was studied. The results show that: 1) The time effect of bearing capacity of steel pipe pile is obvious, and increases rapidly. 2) The recovery coefficient of side resistance of steel pipe pile is much larger than that of end resistance. 3) The recovery of the clay strength around the pile is the main reason for the increase of the side resistance of the steel pipe pile. 4) Although the sand layer is the main part of side resistance of pile, its contribution to side resistance growth is less than that of cohesive soil. 5) The harder the holding layer, the worse the recovery of end-bearing and capacity.