砂土场地光热发电新型高强预应力混凝土短桩基础受力特性研究  

Study on mechanical characteristics of a new PHC short pile foundation for solar power generation in sandy soil

作　　者：李红星 冯世进[2,3] 何邵华 张晓磊[2,3] 孙达明 LI Hong-xing;FENG Shi-jin;HE Shao-hua;ZHANG Xiao-lei;SUN Da-ming(Northwest Electric Power Design Institute Co.,Ltd.of China Power Engineering Consulting Group,Xi’an,Shaanxi 710075,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]中国电力工程顾问集团西北电力设计院有限公司,陕西西安710075 [2]同济大学地下建筑与工程系,上海200092 [3]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩土力学》2021年第12期3217-3226,3237,共11页Rock and Soil Mechanics

摘　　要：高强预应力混凝土(PHC)短桩基础是一种新型太阳能电站发电元件的支撑结构,通过将PHC管桩伸入2~3 m深的钻孔后灌注混凝土形成。为掌握PHC短桩基础的工作性状,开展了砂土场地基础的侧向荷载、侧向-扭转耦合荷载、循环荷载现场试验。根据柱顶倾角、泥面位移、扭转角和基础内的测试结果分析和对比了PHC短桩基础的受力变形规律以及扭转荷载的影响。进一步基于三维数值模拟,分析了桩帽对基础内力和变形的影响规律。结果表明:PHC短桩基础的变形总体上呈现分阶段特性;扭转荷载使土体加快进入塑性状态,降低了阶段立柱的抗裂性能;桩帽可以有效地减小泥面位移,但对立柱的变形影响不明显;正常使用极限荷载下,循环荷载后的残余变形约为单次荷载下变形的2倍;最后基于现场试验、数值模拟,提出了桩端小变形下m值(土体的水平抗力系数)和A_(g)值(土体剪切模量比例系数)的获取方法以及残余变形的经验获取方法。The PHC short pile foundation is a new type of supporting structure for the power generation element of a solar power generation station.It is formed by inserting a PHC pipe pile into a hole of 2-3 m deep,followed by pouring concrete into the hole.To explore the working behavior of the PHC short pile foundation,field tests were carried out on the sand foundation under the lateral loading,coupled lateral and torsion loading and cyclic loading,respectively.According to the results of inclination of the column top,the displacement at the ground surface and the bending moment along the foundation,the force and deformation characteristics of the PHC short pile foundation and the influence of torsion were analyzed.The influence of pile cap on the inner force and deformation of foundation were then analyzed based on three-dimensional numerical simulation.The results show that the deformation of PHC short pile foundation can be divided into three phases.Torsional loads accelerate the occurrence of the soil plasticity and reduce the crack resistance of pile.The pile cap can efficiently reduce the mudline displacement with little influence on the pile deformation.Under normal ultimate load,the residual deformation after cyclic load is about 2 times of that under single load.Finally,based on the field tests and numerical simulation,the methods for obtaining the proportionality coefficient of horizontal soil resistance coefficient m and proportionality coefficient of soil shear modulus A_(g) under small deformation of the pile top are proposed,as well as the empirical methods for obtaining residual deformation.

关 键 词：PHC短桩基础 太阳能电站 现场试验 数值模拟 设计方法 

分 类 号：TU473[建筑科学—结构工程]