重复荷载作用下支盘桩工作性状的模型试验研究

Model Test Research of the Piles with Branches and Plates under Repeated Load

设计了一个室内模型试验来研究支盘桩在重复荷载作用下的承载和变形性能。试验证明:支盘桩在其极限承载力约75%的荷载重复作用下变形增加很小,工作性能十分稳定;支盘桩与普通等直径桩相比,其承载力和抗变形能力十分优越;支盘桩的荷载传递机理是十分复杂的,盘附近土体对桩周的摩擦阻力在不同荷载作用下有时为正有时为负;当两盘的间距在2D(D为盘直径)以下时,桩周的摩擦力对桩的承载力贡献很小,在每次加卸载后土体会建立新的固结平衡状态。文章根据桩周土体土拱的形成和变化情况对上述有关现象进行了分析,还对设计支盘桩时确定合理的桩间距和盘间距提出了自己的观点。

A model test equipment had been designed to consider the bearing capacity behavior and deformation behavior of the piles with branches and plates under repeated load. It was proved that the deformation increment was small and working behavior was very stable as the pile under the load less than 3/4 of limit bearing capacity; the bearing capacity and resistance of deformation were better compared with equal diameter pile ; the load transfer mechanism of the pile with branches and plates was really complex, the skin friction of the silt around the plates was positive or minus as under the different load. When the distance of plates was less than 2D （D is the diameter of plate）, the contribution of skin friction to beating capacity was very small. After each load shedding, the silt would found a new balance and new physical property. According to the principle of soil arch effect, the article analyzed these above phenomena, and suggested new points about the distance of piles and the distance of plates.