黄土地区螺杆桩与CFG桩复合地基承载特性对比研究

Comparative Research on Composite Foundation Bearing Characteristics of Screw Piles and CFG Piles in Loess Area

为研究粉土地基中螺杆桩的承载特性,以新建吴忠—中卫铁路为工程背景,采用室内模型试验对比分析螺杆桩和CFG桩复合地基承载特性。分析结果表明:在相同桩径和桩长的情况下,螺杆桩复合地基承载力较CFG桩复合地基高39%;螺杆桩的轴力在直杆段与螺纹段交界点出现明显拐点;CFG桩复合地基顶部存在负摩阻区,而螺杆桩复合地基在直杆段与螺纹段交界点下方出现负摩阻区,在工程设计、施工中应注意变截面处的处理。

In order to study the bearing behaviors of screw pile composite foundation in silt soil, comparison analysis of composite foundation bearing characteristics of screw pile and CFG pile were conducted through indoor model tests by taking the newly built Wuzhong-Zhongwei railway as the engineering background.The results show that the bearing capacity of screw pile composite foundation is higher than that of CFG pile composite foundation by 39%with the same pile diameter and pile length,the axial force of the screw pile has obvious inflection point at the junction point between the straight pile section and the screw thread section,there is negative friction zone on the top of CFG pile composite foundation,which appears below the junction point between the straight pile section and the screw thread section of screw pile composite foundation,and attention should be paid to the variable cross-section treatment in engineering design and construction.