摘要
为了研究钻机的振动荷载对峡谷裸岩深水地区桥梁桩基筑岛平台的稳定性和桩孔形状的影响机制,以贵州省北盘江贞望大桥6号桥墩桩基为研究对象,基于动力反应分析,利用FLAC 3D对钻机冲击振动作用下筑岛平台的位移响应规律进行了模拟分析。研究结果表明:水平和竖向位移最大值都出现在平台坡肩,筑岛平台顶面水平位移随着X方向(模型长度方向)距离的增加先减小后增大,而竖向位移随着X方向距离的增加而减小;在冲击荷载作用下,水平和竖向位移将分别放大1.27和1.37倍,筑岛内部的水平位移随着土体深度的增加迅速衰减,且水平位移影响深度增大了2 m,竖向位移最大值增幅为85%,位于3 m深度处;筑岛位移值随着冲击振动频率的减小而减小,并且冲击振动频率对竖向位移的影响大于水平位移。最后对比分析了10种冲击钻对筑岛平台位移的影响,推荐该工程使用CK-3000型冲击钻机。研究结果可为类似大桥桩基工程施工提供理论指导。
In order to study the influence mechanism of impact and vibration load of the drilling rig on the stability and the pile hole shape of a island platform for bridge pile foundation in gorge area with bare rock and deep water,No.6 pier foundation of Zhenwang Bridge on Beipan River in Guizhou Province was simulated by FLAC3D to analyze the deformation mechanism based on dynamic response analysis.The results showed that both the maximum horizontal and vertical displacements all appeared on the slope shoulder of the island platform,while the horizontal displacement of the top surface started to decrease and then increased with the increase of the model length direction(X),and the vertical displacement continued to decrease with the increase of X direction.Under the action of impact load,the horizontal and vertical displacements were respectively magnified by 1.27 and 1.37 times.The horizontal displacement inside the island platform decayed rapidly with the increase of soil depth and the influence depth increased by 2 m,and the increase amplitude of maximum vertical displacement was 85%,where was 3m deep.The displacement of the island platform decreased with the decrease of the impact vibration frequency,and the vertical displacement was greater affected by the impact vibration frequency than the horizontal displacement.At last,the impact of 10 types of percussion drills on the displacement of the island platform were compared and analyzed,and CK-3000 impact drill was recommended for this project.The research results can provide theoretical guidance for pile foundation construction of similar bridges.
作者
王林峰
何静
唐宁
傅奕帆
周楠
WANG Linfeng;HE Jing;TANG Ning;FU Yifan;ZHOU Nan(Key Laboratory of Geological Hazards Mitigation for Mountainous Highway and Waterway of Chongqing Municipal Education Commission,Chongqing Jiaotong University,Chongqing 400074,China)
出处
《人民长江》
北大核心
2021年第12期181-187,共7页
Yangtze River
基金
国家重点研发计划项目(2016YFC0802203)
国家自然科学基金项目(51678097)
重庆市教委科学技术研究项目(KJQN201800706)。
关键词
桥梁桩基
筑岛平台
变形机制
振动荷载
峡谷裸岩深水地区
bridge pile foundation
island platform
deformation mechanism
vibration load
gorge area of bare rock and deep water
