青藏高原碎石土地基混凝土承台式螺旋锚基础原位载荷试验及承载机制分析  

In situ loading test and bearing mechanism analysis of concrete cap type helical anchor foundation for gravel soil ground in the Qinghai-Tibetan Plateau

作　　者：黄勇祥 丁士君 袁小超 翟国光 丁民涛 HUANG Yongxiang;DING Shijun;YUAN Xiaochao;ZHAI Guoguang;DING Mintao(China Energy Engineering Group Hunan Electric Power Design Institute Co.,Ltd.,Changsha 410007,China;College of Architecture and Civil Engineering,Beijing University of Technology,Beijing 100124,China;Institute of Transmission and Transformation Engineering,China Electric Power Research Institute,Beijing 102401,China;State Grid Tibet Electric Power Co.,Ltd.,Lasa 850000,China)

机构地区：[1]中国能源建设集团湖南省电力设计院有限公司,长沙410007 [2]北京工业大学建筑工程学院,北京100124 [3]中国电力科学研究院有限公司输变电工程研究所,北京102401 [4]国网西藏电力有限公司,拉萨850000

出　　处：《建筑结构》2022年第4期148-152,105,共6页Building Structure

摘　　要：螺旋锚是一种施工高效、环保的基础,为支撑其在青藏高原架空输电工程中的应用,揭示碎石土地基螺旋锚基础抗拔承载机制,开展了不同安装角度、不同锚盘个数的单个螺旋锚基础轴向上拔,以及浅埋承台式螺旋锚群锚基础斜向上拔的原位载荷试验。试验结果表明:单个螺旋锚基础竖向上拔荷载-位移关系曲线介于陡降型与直线型之间,主要发生锚盘上部土体局部剪切破坏而进入承载极限状态,呈现深基础承载特性;螺旋锚竖向倾斜角度越大则其轴向抗拔极限承载力越小,但加载初期倾斜角度对承载性能的影响不明显,锚盘越多则承载力越大;浅埋承台式螺旋锚群锚基础在斜拉荷载作用下承台和螺旋锚均发挥了一定的抗拔和抗倾覆作用,其中竖向位移20mm时浅埋承台因与地基相互作用而先期进入极限状态,随后主要由螺旋锚继续抵抗基础顶部增量荷载作用,另外群锚主要通过对承台的不均匀作用力来抵抗倾覆力矩。Helical anchor is a kind of high-efficiency construction and environmental protection foundation.In order to support its application of the overhead power transmission project in the Qinghai-Tibet Plateau,and to reveal the anti-uplift bearing mechanism of the helical anchor foundation for gravel soil ground,the in-situ loading tests of the single helical anchor foundation with different installation angles and different number of anchor plates under the axial uplift loading,and the shallow-buried cap type helical anchor group foundation under the oblique uplift loading were carried out.The test results show that the vertical uplift load-displacement relationship curve of a single helical anchor foundation is between the steep drop type and the straight type,and the local shear failure of the upper part of the anchor plate mainly occurs and enters the bearing limit state,showing the bearing characteristics of the deep foundation;The greater the vertical tilt angle of the helical anchor,the lower the ultimate axial uplift bearing capacity,but the inclination angle at the beginning of loading has no obvious effect on the load-bearing performance.The more anchor plates,the greater the bearing capacity.Under the oblique uplift loading,both the cap and the helical anchor of the shallow-buried cap type helical anchor group foundation play a certain anti-uplift and anti-overturning effect.When the vertical displacement is 20 mm,the shallow-buried cap will initially enter the limit state due to the interaction with the ground,and then the helical anchor will continue to resist the load on the top of the foundation.In addition,the group anchors mainly resist the overturning moment by the uneven force on the cap.

关 键 词：碎石土 螺旋锚 承台 锚盘 载荷试验 承载机制 

分 类 号：TU476.9[建筑科学—结构工程]