同步同心式斜撑桩侧摩阻力现场试验研究

Field Test Study on Side Friction of Synchronous Concentric Inclined Strut Pile

依托实际工程,对同步同心式斜撑桩侧摩阻力进行现场载荷试验研究。分析了各级荷载作用下斜撑桩的应变、轴力、桩侧摩阻力的性状,对比了斜撑桩钢管带肋与不带肋的受力特性。试验结果表明:斜撑桩上部的侧阻力先发挥作用,其工作特性与摩擦桩相似;试验桩极限承载力约为1400 kN,粉土层中水泥土-桩周土界面侧摩阻力极限值约为80 kPa,此时对应的水泥土-钢管界面侧摩阻力约为165 kPa;内芯钢管和水泥土侧摩阻力分布规律一致,其比值约为水泥土和钢管外径之比;钢管带肋与否对斜撑桩受力特性的变化几乎没有影响。

Relying on the actual project,the side friction of synchronous concentric inclined strut piles is studied by field load test.The behavior of strain,axial force and pile side friction of inclined strut piles under various loads is analyzed,and the mechanical characteristics of steel pipe with ribs and without ribs of inclined strut piles are compared.The test results show that,the lateral resistance of the upper part of the inclined strut pile plays a role first,and its working characteristics are similar to those of the friction pile;the ultimate bearing capacity of the test pile is about 1400 kN,and the limit value of the side friction resistance of the cement-soil-soil interface around the pile in the silt layer is about 80 kPa,at which time the corresponding side friction resistance of the cement-soil-steel pipe interface is about 165 kPa;the distribution law of side friction resistance of inner core steel pipe and cement-soil is consistent,and its ratio is about the ratio of cement-soil to outer diameter of steel pipe;whether the steel pipe is ribbed or not has little effect on the change of the mechanical characteristics of inclined strut piles.