坡地条件下水平受荷单桩p-y曲线法试验与数值模拟  

Experiment and Numerical Simulation of p-y Curve Method for Laterally Loaded Single Pile in Sloping Ground

作　　者：杨明辉[1] 朱刘山 罗宏[1] 冯超博[1] 

机构地区：[1]湖南大学岩土工程研究所,湖南长沙410082

出　　处：《公路交通科技》2017年第8期83-90,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51278184;51678230);教育部新世纪优秀人才支持计划项目(NCET-13-194);湖南省科技重点研发项目(2015CK3003)

摘　　要：为了探究坡地条件与平地条件单桩水平承载性能的差异,首先开展了黏性土45"坡地与平地的水平受荷单桩室内模型对比试验,探讨了两种境况下单桩桩顶荷载-位移曲线和弯矩沿桩身分布规律的不同。结果表明:与平地相比,坡地单桩桩顶的荷载-位移曲线坡度较小,且浅层区域内的桩身弯矩也小于平地单桩,此现象说明,坡体存在因土体缺失而抵抗桩身变形能力减小的坡度效应。然后利用数值分析重复性强的优势,分析了边坡角度对位移沿桩身分布规律的影响。对比分析发现:与试验分析结果相同,即在浅层区域内,边坡侧土体抵抗桩身变形的能力受到削弱,且这种削弱作用随坡角的增大而增大;但削弱现象只存在一个和坡角有关的临界深度以上,该深度以下削弱作用可忽略不计,即可视为平地基桩处理。基于数值分析对存在削弱作用的浅层区域土体的p-y曲线进行了探究,得到了其关键参数桩侧土体极限抗力和初始刚度适用于坡地的修正表达式,从而建立了适用于坡地条件下的p-y曲线法,且得到了临界深度与坡角存在的关系。最后,用该方法计算的桩顶荷载-位移曲线与已有的试验结果以及国外同行的其他算法进行了对比,结果表明理论值与实测数据吻合较好。In order to explore the difference of horizontal bearing characteristics of single pile in sloping ground and horizontal ground,the indoor comparative model test on horizontal loading on single pile in 45°slope and flat ground cohesive soil is carried out,and the differences of load-displacement curves of single pile head and bending moment along the pile are analyzed under 2 conditions. The result shows that the pile head in sloping ground has the smaller slope of load-displacement curve of pile head and the smaller bending moment in the shallow area than those in horizontal ground,which indicates that the sloping ground has a slope effect to resist the pile deformation due to soil loss. Then,taking the advantage of repeatability of numerical analysis,the influence of slope gradient on the distribution of displacement along pile depth is analyzed. The comparative analysis shows that（ 1） same as the result of the model test,the lateral soil of the slope to resist the deformation of pile is reduced in the shallow area,and the greater slope gradient has greater effect on the reduction,but there is only the reduction above the critical depth depending on the slopegradient,the reduction effect is negligible below this depth,and the pile can be regarded as the foundation pile in horizontal ground. Based on the result of numerical analysis,the p-y curves of the soil in shallow area which has reduction effect is discussed,the revised formulas of the ultimate lateral resistance and the initial stiffness of the key parameters near a slope are obtained. Then the p-y curve method suitable for sloping ground is proposed,and the relationship between critical depth and slope gradient is also obtained.Finally,the load-displacement curves of pile head calculated by the proposed method are compared with the test result and other foreign calculations. The theoretical values are in good agreement with the experiment data. The theoretical method can provide reference for engineering design.

关 键 词：桥梁工程 P-Y曲线 数值分析 单桩 坡度效应 

分 类 号：U443.15[建筑科学—桥梁与隧道工程]