黄土区楔形桩-网复合地基承载特性  

Bearing characteristics of composite foundation with tapered pile in loess area

作　　者：邓友生[1,2] 陈茁 杨明辉 吴阿龙 庄子颖 董晨辉 DENG Yousheng;CHEN Zhuo;YANG Minghui;WU A long;ZHUANG Ziyin;DONG Chenhui(School of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China;Plie-supported Structures Research&Test Center,Xi'an University of Science and Technology,Xi'an 710054,China;School of Architecture and Civil Engineering,Xiamen University,Xiamen 361005,China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054 [2]西安科技大学桩承结构研究中心,陕西西安710054 [3]厦门大学建筑与土木工程学院,福建厦门361005

出　　处：《厦门大学学报（自然科学版）》2024年第4期775-784,共10页Journal of Xiamen University：Natural Science

基　　金：国家自然科学基金(51878554);陕西省自然科学基础研究计划项目(2018JZ5012)。

摘　　要：[目的]针对黄土地区中楔形桩-网复合地基的承载性能进行探究.[方法]开展以几何相似常数为第一基本量、重度相似常数为第二基本量的土工模型试验,研究了不同受荷区域基桩承载能力,并通过有限元计算方法进一步分析其承载特性.比较模型试验结果与有限元计算结果,揭示了黄土区楔形桩-网复合地基的荷载沉降、桩身轴力、侧摩阻力、桩土应力比及荷载分担比等分布与变化规律.[结果]复合地基沉降变化总体趋于均匀,荷载-沉降曲线为缓变型;不同受荷区域基桩的桩身轴力、侧摩阻力呈现明显差异性;楔形桩-土相互作用与荷载和深度呈现正相关关系,但存在一定上限;复合地基中楔形桩随荷载增大能有效分散桩身应力,并将荷载由桩体向桩周土传递、由地基中心向外围扩散.[结论]楔形桩-网复合地基表现出良好的承载能力,直接受荷区桩能更高效地发挥楔形桩承载特性,楔形桩在复合地基中很好地实现桩-网-土协同作用.[Objective]The bearing capacity and stability of the whole structure can be improved by the composite foundation,which can exhibit the bearing capacity of the reinforced and natural soil.To tackle the problem of foundation bearing capacity in collapsible loess area and integrate the excellent bearing capacity of tapered pile into composite foundation,herein we conduct the experimental study.[Methods]Soil model tests with geometric similarity constant as the first basic quantity and heavy similarity constant as the second basic quantity are carried out to analyze the bearing capacity of foundation piles in different load areas,and bearing characteristics are further analyzed by the finite element method.A series of load parameters such as load settlement,pile axial force,side friction resistance,pile-soil stress ratio and load sharing ratio of tapered pile composite foundation under loess are studied by comparing these test results with these simulation results.[Results]The settlement of tapered pile-mesh composite foundation changes uniformly with the increase of load,no sudden change of settlement exists,and the load-settlement curve changes slowly.It is found that bearing characteristics of piles in the direct load area differ greatly from those in the non-direct load area through changes of axial force and side friction resistance.These changes in the direct load area are aligned with the typical axial force distribution law of friction piles,and the proportion of side friction resistance in the direct load area exceeds 80%,demonstrating the bearing capacity of tapered piles.However,the pile in the non-directly loaded area endures negative friction resistance under most loads from 20 kPa to 200 kPa,indicating that the pile in the non-directly loaded area does not fully exert its due bearing capacity,and only uses part of the bearing capacity.According to the weakening of the range of positive friction resistance along pile length in the area directly under load,and the flattening of axial force range and gradi

关 键 词：路基工程 楔形桩 桩网复合地基 模型试验 有限元 承载特性 

分 类 号：TU473.1[建筑科学—结构工程]