X形混凝土桩抗拔特性试验研究

利用自行开发的大型土工试验模型槽，进行了等截面积X形桩和圆形桩抗拔性能对比试验研究，比较了二者轴力、桩侧摩阻力及位移的分布和变化规律。X形桩相比圆截面桩侧表面积增加了31.5%，试验结果表明，二者桩侧摩阻力分布规律相同，沿桩长可分为提高区域、衰退区域；摩阻力发挥充分的区域在埋深1.50～3.00 m，此区域中X形桩摩阻力的最小值和峰值都较圆形桩大，相同的桩头位移下X形桩的侧摩阻远大于圆形桩，其极限抗拔力高出圆形桩约16.7%。

Model test study of anti-pulling property of X-shaped concrete pile

Comparative test study of anti-pulling property of X-shaped pile and circular section pile with constant section is carried out in the self-developed large-scale soil test model chamber. The distributions of axial forces, lateral frictions and displacement are analyzed. the lateral surface of The X-shaped pile is 31.5% greater than the circular section pile; but the distributions of lateral friction force along pile shaft are almost the same, which consist of two different zones, raising zone and decay zone. The friction force is fully exerted from 1.5 m to 3 m away the pile head, and the minimum value and peak value of X-shaped pile in the area are larger than circular section pile. Under the same settlements, the lateral friction force of X-shaped pile is greater than circular pile. The results show that the ability of X-shaped pile to resist uplift force is 16.7% higher than that of the circular pile.