多节旋挖挤扩DX桩基承载特性及失效机制试验研究

项目名称： 多节旋挖挤扩DX桩基承载特性及失效机制试验研究

项目编号： No.51478035

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 建筑科学

项目作者： 张德华

作者单位： 北京交通大学

项目金额： 80万元

中文摘要： 多节旋挖挤扩DX 桩基（简称DX桩）是近年兴起的一种异型多承盘桩基形式，因其可显著提高桩基承载力、减少沉降、降低桩长及节约原材料，在高速公路、铁路、港口码头甚至大型LNG储油罐的桩基工程得到广泛应用。试验报告和工程应用均表明该桩型的优越性与发展潜力,因此对该桩的竖向承载性能与其设计方法研究，近年来已成为桩基工程研究人员的新热点。但因多承力盘的存在改变了传统等截面桩的荷载传递规律和沉降特性，桩土之间相互作用较为复杂，研究人员对DX桩荷载传递方式等科学规律的认识还很不充分。本课题拟通过一系列模型试验、理论分析与数值模拟等多种手段，对DX桩的荷载传递机理及承载特性进行研究，掌握承力盘、桩身与土体的相互作用规律，从而建立DX桩竖向承载力设计方法。研究成果将大大发展桩基设计理论。尤其当前我国高速铁路、公路工程中超长桩基越来越多，本课题研究成果及应用既具有重要的理论意义，又具有广泛的工程实用价值。

中文关键词： 桩基础；承载机理；模型试验；竖向承载力；失效模式

英文摘要： Thanks to some remarkable advantages, such as high bearing capacity, small settlements and pile length reduction and raw material saving,rotary extruded-expanded cast-in-place concrete pile (hereinafter referred to as DX pile) with expanded plates, a new kind of pile with varied cross-section recently developed,has been widely applied in pile foundation of civil engineering, expressway bridges engineering, high speed railway bridge engineering,port engineering,even large LNG project.Since test reports and engineering applications show the superiority and development potential of this type of pile, study of bearing characteristics and design method of DX pile has undoubtedly become a new hot spot for pile foundation engineers and researchers in recent years. As the existence of multiple plates have greatly changed load transfer law and characteristics of settlements of traditional pile with uniform section for its pile-soil interaction complexity, exploration of DX pile load transfer science law remains very insufficient.The study for this application will carry a series of model tests, site tests on a single model pile to identify the load transfer characteristic,deformation and failure mechanism of DX pile, and try to establish DX pile bearing capacity design method, which fills a gap of this research field. The research results will not only promote development of pile foundation design theory ,but provide an important solution of practical engineering problems, especially with the rapid development of super-long pile foundation in high speed railway engineering, highway engineering currently.It is expected that the study for this application will have important effectiveness for both academic and pratice.

英文关键词： pile;bearing mechanisim;mmodel test;vertical bearing capacity;failure mode