中文摘要：

为对比研究等截面面积与等截面周长Y形桩与圆形桩的竖向承载性能,基于自主研发的大型桩基模型试验加载系统,通过在桩体内埋设钢筋计,桩端土体内布设土压力盒和砂雨法施工埋设桩体,进行了Y形桩与圆形桩承载机理对比模型试验研究。结果表明：与等截面圆形桩相比,Y形桩极限承载力是圆形桩的1.60倍,桩侧表面积是圆形桩的1.56倍,极限承载力的提高与桩侧表面积增大效果基本一致,在各级荷载作用下圆形桩的端阻力均小于Y形桩的端阻力,异形桩端截面增大了其端阻力;与等周长圆形桩相比,Y形桩极限承载力是圆形桩的84%,但混凝土用量仅为圆形桩的41%,单位体积混凝土发挥的极限承载力为圆形桩的2.04倍,在各级荷载作用下Y形桩总桩侧阻力均大于圆形桩。

英文摘要：

In order to investigate and compare the vertical bearing behaviors of Y-section pile and circular pile with the constant section area and the same section perimeter,by means of burying steel bar gauge in piles,laying the earth pressure cell under the pile tip,and installing the piles using sand pour method,the comparative model test research on the bearing mechanism between Y-section piles and circular piles was carried out based on the self-developed loading system of large-scale pile foundation model test.The results show that the ultimate bearing capacity and the pile side surface of Y-section pile are 1.60 times and 1.56 times those of circular pile with the constant section,respectively;the effect of improving ultimate bearing capacity is consistent with that of the increase of pile side surface;and the tip resistance of the circular pile is always lower than that of the Y-section pile under different load levels due to the fact that the special Y-section pile tip section enhances the tip resistance.The ultimate bearing capacity of Y-section pile is 84%that of the circular pile with the same perimeter,however,the amount of concrete in Y-section pile is only 41% of that in circular pile.The ultimate bearing capacity of per unit volume ofconcrete for Y-section pile is 2.04 times that for circular pile;the total side resistance of the Ysection is larger than that of the circular pile under each load level.