陡坡段穿越溶洞桩基水平承载特性离心试验  

Centrifugal Test on Horizontal Bearing Characteristics of Pile Foundation via a Karst Cave in Steep Slope Area

作　　者：李宇杰 冯忠居[1] 何静斌 张聪[1] 邓友生[3] 江冠 LI Yu-jie;FENG Zhong-ju;HE Jing-bin;ZHANG Cong;DENG You-sheng;JIANG Guan(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;Northwest Survey and Design Research Institute of China Electric Construction Group,Xi'an 710065,Shaanxi,China;School of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,Shaanxi,China;School of Urban and Rural Planning and Architectural Engineering,Shangluo University,Shangluo 726000,Shaanxi,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]中国电建集团西北勘测设计研究院有限公司,陕西西安710065 [3]西安科技大学建筑与土木工程学院,陕西西安710054 [4]商洛学院城乡规划与建筑工程学院,陕西商洛726000

出　　处：《中国公路学报》2025年第2期197-206,共10页China Journal of Highway and Transport

基　　金：国家重点研发计划项目(2018YFC1504801-04);国家自然科学基金青年科学基金项目(4190070568)。

摘　　要：为研究陡坡地段桥梁桩基穿越溶洞时的水平承载特性,以广那高速公路工程为依托,考虑陡坡和溶洞的影响,开展了横轴向受荷桩基的离心模型试验。在地基坡度、溶洞尺寸及位置一定的情况下,设置桩基的长径比分别为6.5、9.0、11.5和14.0,在桩顶逐级施加水平荷载,分析了长径比变化对桩基水平极限承载力、桩身弯矩以及桩侧土抗力的影响,给出了弯矩最大值和土抗力最大值的位置范围和分布规律。结果表明:陡坡段桩基穿越溶洞的情况下,长径比小于14.0时,桩基的水平极限承载力随长径比增大逐渐增大,桩身弯矩沿桩基埋深先增大后减小至0,最大值出现在距桩顶3.5~4.5倍桩径范围内。长径比从6.5增大至14.0时,弯矩最大值逐渐增大,桩侧土抗力沿桩基埋深先增大后减小至0,土抗力最大值出现在距桩顶2.5~4.5倍桩径范围内。随长径比增大,桩侧土抗力最大值逐渐减小,土抗力最大值的位置逐渐下移。长径比小于等于11.5时,桩基表现为刚性桩的承载特性;长径比大于11.5时,表现为弹性桩的承载特性;不同长径比条件下桩前土抗力均小于桩后土抗力。研究结果可为陡坡岩溶区桩基水平承载力计算提供参考。To investigate the horizontal bearing characteristics of bridge pile foundations on steep slopes via karst caves,a centrifugal model test of transverse axially loaded pile foundations is conducted based on the Guangna Highway project,considering the effects of steep slopes and karst caves.Under a certain foundation slope,cave size,and location,the length-to-diameter(L/D)ratios of the pile foundation are set to 6.5,9.0,11.5,and 14.0,and the horizontal load on the top of the pile is applied step-by-step.The effects of changes in L/D ratio on the horizontal ultimate bearing capacity of the pile foundation,pile bending moment,and soil resistance on the pile side are analyzed,and the location range and distribution law of the maximum values of the bending moment and soil resistance are determined.The results show that the horizontal ultimate bearing capacity of the pile foundation increases with the L/D ratio when the pile foundation passes through the karst cave in steep slope areas under an L/D ratio of less than 14.0.The pile bending moment increases and then decreases to zero along the depth of the pile foundation,and the maximum value appears in the range of 3.5-4.5 times the pile diameter from the pile top.The maximum value of the bending moment increases gradually as the L/D ratio increases from 6.5 to 14.0.The soil resistance on the pile side increases and then decreases to zero along the depth of the pile foundation,and the maximum value of the soil resistance appears in the range of 2.5-4.5 times the pile diameter from the pile top.With an increase in the L/D ratio,the maximum value of the soil resistance on the pile side decreases gradually,and the position of the maximum value of the soil resistance gradually decreases.When the L/D ratio is less than or equal to 11.5,the pile foundation exhibits the bearing characteristics of a rigid pile,whereas when the L/D ratio is greater than 11.5,the foundation exhibits the characteristics of an elastic pile.The soil resistance in front of the pile is lower than that

关 键 词：桥梁工程 岩溶桩基 离心试验 承载特性 陡坡 长径比 

分 类 号：U443[建筑科学—桥梁与隧道工程]