扩径桩承载性状及其Q-s曲线的幂双组合数学模型描述  

BEARING BEHAVIORS AND DESCRIPTION OF Q-s CURVES OF PILES WITH EXPANDED DIAMETER BASED ON POWER-HYPERBOLA COMBINED MODEL

作　　者：蒋建平[1] 高广运[2] 顾宝和[3] 

机构地区：[1]上海海事大学海洋环境与工程学院,上海201306 [2]同济大学土木工程学院地下系,上海200092 [3]建设部综合勘察研究设计院,北京100007

出　　处：《工程力学》2010年第11期120-126,共7页Engineering Mechanics

基　　金：国家自然科学基金项目(50678128);上海市教委科研创新项目(09YZ250);上海海事大学科研基金项目(2009160);港口;海岸及近海工程校重点学科项目(A2010030);上海市第4期本科教育部高地建设项目(B210008G)

摘　　要：为加强对扩径桩的认识和推广其实际应用,对扩径桩的承载性状及其桩顶荷载-桩顶沉降曲线(即Q-s曲线)的描述进行了研究。研究发现,3根现场试验扩径桩的Q-s曲线属缓变型,扩径桩的破坏是以扩径部分下土体的剪切破坏和桩端土体的贯入破坏为主。构建的幂函数-双曲线组合数学模型对3根现场试验扩径桩Q-s曲线的拟合效果很好,相关系数R都为0.9997以上,且组合模型的拟合效果好于单个的幂函数模型和双曲线模型;以3根桩中的1根为代表,用前面的11组试验数据拟合后得出的方程式来预测后面的4组数据的桩顶荷载,预测效果好,预测的相对误差为?0.26%―1.32%。结果表明:该文构建的幂函数-双曲线组合数学模型适合用来描述扩径桩的Q-s曲线。In order to understand the piles with expanded diameter perfectly and to widen their actual application, the bearing behaviors was studied and load-settlement curves （that is Q-s curves） were obtained for piles with expanded diameters. It was found that the shapes of Q-s curves change slowly, and the damage of piles was in the form of shear damage of the soil under the branch and the penetrating damage of the soil under the pile end. Q-s curves of the 3 field testing piles were well fitted by the power-hyperbola combined mathematical model, and the correlativity coefficients R was over 0.9997, better than the power function model or the hyperbola model. The fitting equation from the former 11 groups of testing data of a pile was used to forecast the load of the other 4 groups, and prediction was good. The relative error between the prediction value and the actual measurement was ？0.26%―1.32%. So it is can be concluded that the power-hyperbola combined mathematical model is appropriate to describe Q-s curves of piles with expanded diameters.

关 键 词：桩 数学模型 承载性状 幂函数模型 双曲线模型 Q-S曲线 

分 类 号：TU473[建筑科学—结构工程]