斜坡上嵌岩抗拔桩竖向承载变形特性模型试验及数值模拟  

Model test and numerical simulation of vertical bearing capacity and deformation characteristics of rock-socketed uplift pile in sloped ground

作　　者：季雨坤 王钦科 赵国良 张健 马建林[4] JI Yu-kun;WANG Qin-ke;ZHAO Guo-liang;ZHANG Jian;MA Jian-lin(State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang,Sichuan 621010,China;POWERCHINA Sichuan Electric Power Engineering Co.,Ltd.,Chengdu,Sichuan 610041,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China)

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [2]西南科技大学土木工程与建筑学院,四川绵阳621010 [3]四川电力设计咨询有限责任公司,四川成都610041 [4]西南交通大学土木工程学院,四川成都610031

出　　处：《岩土力学》2023年第6期1604-1614,1624,共12页Rock and Soil Mechanics

基　　金：国家重点研发计划(No.2016YFC0802203);四川省科技计划(No.2023NSFSC0881);中央高校基本科研业务费专项资金(No.2022QN1038);江苏省基础研究计划项目(No.BK20221135)。

摘　　要：随着我国输电线路工程逐步进入西部山区,越来越多的输电塔基础需要修建在陡峭的山坡上。然而,斜坡桩基在强风、雪等极端气候的抗拔承载变形特性研究不足,现行规范也尚无完善说明。基于此,开展了平地与斜坡上嵌岩抗拔桩的室内模型试验,对比分析了荷载-位移曲线、地面变形及裂缝扩展、破坏模式、桩身轴力、桩侧摩阻力及桩-岩相对位移。使用试验结果与ABAQUS数值模拟结果相比较,在验证模型可靠性的基础上,进一步研究了斜坡坡度对嵌岩抗拔桩承载变形特性的影响。结果表明,平地与斜坡下的荷载-位移曲线变化规律一致,均呈陡变型。斜坡对嵌岩抗拔桩的承载变形特性具有不利影响,当斜坡坡度在0°~30°范围内变化时,斜坡坡度对极限承载力的削弱影响呈近似线性增加(0%~12.8%)。随着斜坡坡度增加到45°时,斜坡对嵌岩抗拔桩极限承载力的削弱影响急剧凸显(25.9%)。斜坡上的基岩破坏面主要发生在下坡3.2d(d为桩径)、角度为120°的扇形范围内,逆坡破坏范围约为1d,不同于平地呈对称、复合形的破坏。值得注意的是,当桩顶荷载达到约80%的极限承载力时,平地地表或斜坡下坡出现了可见的裂缝。该研究成果为斜坡上输电塔桩基抗拔优化设计及规范完善提供了科学依据。As transmission line projects continue to expand into the western mountainous regions of China,the need for more transmission tower foundations on steep hillsides has increased.However,research on the uplift bearing deformation characteristics of pile foundations under high-intensity wind and snow scenarios on sloped ground is lacking,and current specifications are insufficient.Therefore,laboratory model tests were conducted on rock-socketed uplift piles on both flat and sloped ground to investigate load-displacement curves,ground deformation and crack propagation,failure mode,axial force of pile,side friction of pile,and relative displacement between the pile and rock.ABAQUS numerical simulation results were compared to the model test results to validate the reliability of the numerical model and investigate the influence of steepness(slope angle)on the bearing capacity and deformation characteristics of rock-socketed uplift piles.The results demonstrate that the load-displacement curves for flat and sloped ground have similar steep shapes,and sloped ground can have an adverse impact on the bearing capacity and deformation characteristics of rock-socketed uplift piles.The decrease in pile bearing capacity is positively correlated to the steepness of the slope,with a decrease of 0%–12.8%for slopes of 0º–30ºand up to 25.9%for a slope of 45º.Bedrock failure surfaces mainly occur in the downhill slope within a range of 3.2d(d is pile diameter),as well as within a fan-shaped range of 120º,while the failure range on adverse slopes is about 1d,which is different from symmetrical and composite failure on flat ground.When the load on the top of the pile reaches approximately 80%of its ultimate bearing capacity,visible cracks can be observed in flat or downhill areas of sloped ground.These research findings offer a scientific basis for improving the design and specifications of uplift resistance capacity in transmission tower foundations on sloped ground.

关 键 词：斜坡 嵌岩抗拔桩 承载变形特性 室内模型试验 数值模拟 

分 类 号：TU473.1[建筑科学—结构工程]