河北唐山曹妃甸地区混凝土管桩承载力试验研究

Experimental research on bearing capacity of PHC pile in Caofeidian area TangShan city HeBei province

文章通过在预应力高强混凝土管桩(PHC)桩周各土层界面处埋设应变式钢筋计的静载荷试验,研究软土地基PHC管桩的单桩竖向极限承载力,分析了桩侧阻力、桩端阻力的分布规律。认为:(1)当第一层土为尚未完成自重固结的土层时,其土层范围内桩侧阻力值非常小;(2)桩身轴力自上而下传递,土层提供的桩侧阻力存在深度效应;(3)试桩表现为典型的端承摩擦桩性状,桩端阻力占荷载比重不超过5%,考虑桩顶相对位移对桩端阻力的发挥作用,引入桩顶位移修正系数后,利用规范公式计算结果与试验结果较接近。

The article studied the bearing capacity of PHC pile in soft foundation,distribution rules of shaft and tip resistance by static loads test with strain gauges mounted at the interface of soil layer.It is concluded： 1） The values of shaft resistance are very small within the cover depth of the first soil layer because of unconsolidated.2） Axial force transmitted from top to bottom.The values of shaft resistance have some connected with depth.3） Test piles with end-resistance no more than 5% of total loads are obviously friction piles.When tip displacements were considered,the results by calculation are acceptable according to experiments.