楔形桩与等直径桩承载特性对比模型试验研究

摘要

针对楔形桩的承载特性,开展砂土中竖向压荷载、水平向荷载以及地面堆载作用下等混凝土用量楔形桩和等直径桩承载特性对比模型试验,测得不同荷载等级下桩顶荷载-位移关系曲线以及桩侧摩阻力、桩端阻力、桩侧土压力、桩顶下拽位移和桩身下拽力等分布规律;探讨楔形桩与等直径桩在竖向抗压、水平向承载力以及负摩阻力特性的异同点,分析楔形角对砂土中基桩的承载特性的影响规律.研究结果表明:在本文试验条件下,砂土中楔形桩的单桩竖向抗压力和水平向极限承载力约分别为等混凝土用量等直径桩的0.75倍和1.26倍;楔形桩的桩顶下拽位移与等直径桩的下拽位移相比减小1/5～1/4.%Based on model test method,comparative model tests on bearing capacities of tapered pile and equal diameter pile with the same concrete usage embedded in sand under vertical compressive load,horizontal load and surcharge load were carried out.The load versus displacement curves,pile shaft friction,tip resistance,horizontal earth pressure,downdrag and dragload were measured.The differences between the tapered pile and equal diameter pile were discussed,and the advantages and disadvantages of tapered pile were analyzed.The results show that,in this model test condition,the vertical compressive and horizontal bearing capacities of tapered pile are nearly 0.75 times and 1.26 times of those of equal diameter pile.The downdrag of tapered pile is 1/5-1/4 reduced compared with that of the equal diameter pile.