中文摘要：

研制异型桩是降低负摩阻力的重要措施之一,对目前能降低负摩阻力的异型桩的种类和特征进行了系统分析与总结,并介绍了作者已授权的一项国家发明专利-种端部螺纹X 形变截面预制管桩及其施工方法.通过FLAC3D 软件分别模拟了圆形等截面桩和锥形异型桩在相同地面堆载的情况下桩身轴力的分布情况,结果表明锥形纵截面的设置可以有效降低负摩阻力的影响.阐述了端部螺纹X 形变截面预制管桩能更显著降低负摩阻力的机制,研究成果可为端部螺纹X 形变截面预制管桩的设计和推广应用提供一定的理论基础.

英文摘要：

Development of special-shaped pile is one of the important measures to reduce the negative friction, the types and characteristics of the current special-shaped pile reducing the negative friction were analyzed and sum-marized, and the authors introduced a state authorized invention patent -- The thread at the end of the X shaped precast pipe pile and its construction method. Distribution of circular section pile and tapered special-shaped pile on the same surface load under the condition of axial force of pile were simulated respectively by FLAC3D software. Results show that the effect of longitudinal section of tapered settings can effectively reduce the negative friction. The mechanism of the thread at the end of the X shaped precast pipe pile which can significantly reduce the nega-tive friction was elaborated. The theoretical foundation for design and application of research results for the thread at the end of the X shaped precast pipe piles was provided.