水利工程中大直径PHC管桩承载力试验研究

结合某一水利工程大直径PHC管桩的地基处理应用，开展了单桩竖向抗压静载试验和单桩水平静载试验，并通过在管桩预制阶段安装钢筋应力计，研究分析了静载试验中桩身的荷载传递规律。研究表明：本工程中混凝土强度C80、外径800 mm、内径580 mm的PHC管桩的单桩竖向抗压承载力极限值不小于2 880 kN，桩顶荷载几乎全部由桩周侧摩阻力承担，桩端阻力发挥较小，属于典型的摩擦型桩。桩身轴力、桩侧摩阻力和桩端阻力均随着竖向荷载的施加而逐渐增大，并沿深度呈衰减分布。水平荷载下的桩身弯矩呈弓形分布，最大弯矩发生在距桩顶约0.2～0.3倍桩长截面处，单桩水平临界荷载值在150 kN左右。

An investigation into stress characteristics of PHC pipe piles in hydraulic structure

A series of vertical static load tests and lateral load tests of PHC pipe pile were conducted in this study. Stress gauges were installed to measure and analyze the load transfer mechanism of pile. It was found that the limit vertical bearing capacity of a PHC pipe pile with C80 grade in concrete strength, 800mm in external diameter and 580 mm in internal diameter was larger than 2880kN. The working load was primarily transferred as shaft resistance instead of tip resistance, behaving as a typical floating pile. Axi-al force, shaft resistance and tip resistance were increased with increasing vertical working load and de-creased along pile shaft. An arched type profile of bending moment due to lateral working load was ob-served and the maximum bending moment occurred at the depth of about 0.2~0.3 times pile length. The critical lateral bearing capacity was about 150kN in this study.