基于水-热-力耦合模型的钻孔灌注桩承载力影响因素分析  

Analyzing the factors controlling the bearing capacity of cast-in-place piles based on a thermo-hydro-mechanical coupling model

作　　者：刘乃飞[1] 李宁[1,2] 何敏[1,3] 徐栓海[1,4] 

机构地区：[1]西安理工大学岩土工程研究所,陕西西安710048 [2]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000 [3]中国电建集团西北勘测设计研究院有限公司,陕西西安710065 [4]中煤科工集团西安研究院有限公司,陕西西安710077

出　　处：《冰川冻土》2014年第6期1471-1478,共8页Journal of Glaciology and Geocryology

基　　金：西安理工大学博士学位论文创新基金项目(207-002J1306);国家自然科学基金创新群体项目(40821001)资助

摘　　要：针对广大寒区普遍存在的冻胀-融沉影响桩基承载力问题,以清水河大桥灌注桩为例,基于建立的饱和冻土水-热-力三场耦合模型及研发的3G2012软件系统,深入研究了温度变幅、桩和地基土的传导系数、导水系数、回冻时间等因素对其承载力的影响,揭示了其承载的内在热力学机理.结果表明:钻孔灌注桩承载力随温度发生波动变化,冬季桩基的极限承载力近似为夏季的1.2倍;地基的导水系数提高一个数量级,加剧了地基土中的水分迁移及冻胀融沉变形,进而影响桩基承载力;冻土回冻时间对桩基承载力也有较大影响.以上结论为寒区岩土工程的设计与施工提供量化的科学依据.The bearing capacity of pile foundation is severely affected by the changes in seasonally freezing and thawing processes. By using a thermo-hydro-mechanical coupling model for saturation frozen soil and its analysis software 3G2012, the influences of temperature fluctuation, conductivity coefficient, transmissibility coefficient and refreezing time on the bearing capacity of cast-in-place pile in cold regions are studied in this paper, in which the cast-in-place piles in Qingshuihe Bridge are taken as an example. The study achievements reveal the thermo- dynamicsmechanism of the beating capacity of cast-in-place pile. It is found that 1 ） beating capacity shows a fluctuate change with temperature and the ultimate bearing capacity of the pile foundation in winter is about 120% as it in summer; 2） when the transmissibility coefficient within subsoil has one order enhanced, the water migration will be more active and the frost heaving and thawing settlement processes will significantly intensify, affecting the pile＇s beating capacity; 3 ） also, the process of refrozen has some influence on the bearing capacity of the pile. Further study may provide scientific basis for design and construction of projects in cold regions.

关 键 词：水-热-力耦合模型 钻孔灌注桩 承载力 含冰量 

分 类 号：P642.14[天文地球—工程地质学]