叶片宽度对多年冻土区螺旋桩承载特性影响试验研究  

Experimental Study on Influence of Blade Width on Bearing Characteristics of Screw Pile in Permafrost Region

作　　者：张维嘉 郭春香[1] 蒋代军[1] 刘涛 杨迅 ZHANG Weijia;GUO Chunxiang;JIANG Daijun;LIU Tao;YANG Xun(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;PowerChina Guiyang Engineering Co.,Ltd.,Guiyang 550000,China)

机构地区：[1]兰州交通大学土木工程学院,兰州730070 [2]中国电建集团贵阳勘测设计研究院有限公司,贵阳550000

出　　处：《兰州交通大学学报》2024年第5期121-129,共9页Journal of Lanzhou Jiaotong University

基　　金：国家自然科学基金(41902272);甘肃省自然科学基金(20JR10RA235)。

摘　　要：多年冻土区连续叶片螺旋桩在季节活动层无螺旋叶片,多年冻土层螺旋叶片与冻土咬合,竖向承载性能良好。通过模型试验方法对多年冻土区螺旋桩叶片宽度的承载特性进行了试验,研究了其承载力曲线与轴力曲线,最后提出多年冻土地区螺旋桩单桩承载力估算公式,主要得到如下结论:无叶片的桩承载力远小于带有叶片的螺旋桩,叶片宽度对螺旋桩承载力影响显著,螺旋桩承载力随叶片宽度增加逐渐增加。不同叶片宽度的螺旋桩,桩身轴力沿桩身深度方向逐渐递减,随着荷载增加桩端承载力逐渐增加,无螺旋叶片的桩桩身轴力变化远小于带有螺旋叶片的桩,桩身无螺旋叶片区域轴力变化幅度与无螺旋叶片的桩相同,桩身有叶片区域轴力变化幅度远大于无叶片区域,随着叶片宽度增加桩身轴力变化幅度逐渐增大。极限承载力随外径与内径比增大,正比例增大,试验可得到外径越大,螺旋桩的极限承载力越高。使用改进公式计算单桩竖向承载力在工程实践中可以有效估算单桩承载力设计值。Continuous blade screw piles in permafrost regions have no screw blades in the seasonal active layer,and the screw blades in the permafrost layer are interlocked with the permafrost,resulting in good vertical bearing performance.To explore the bearing characteristics of continuous blade screw pile in permafrost region,the vertical bearing characteristics of screw pile in permafrost region are explored by means of laboratory test.Finally,the theoretical calculation formula of vertical bearing capacity in permafrost region is put forward,and the main conclusions are as follows:The bearing capacity of no blades in the load-settlement curves of screw piles with different pitch is much less than that of screw piles with blades,and the pitch has little influence on the bearing capacity of screw piles,and the ultimate load does not increase linearly with the increase of pitch,With the increase of load,the bearing capacity of pile tip increases gradually,and the axial force change of pile without spiral blades is far less than that of pile with spiral blades.The variation amplitude of axial force of screw pile without spiral blades is the same as that of no spiral blades.The variation amplitude of axial force of screw pile with blades is much larger than that without blades,and gradually increases with the increase of blade width.When the pitch is small,the soil between the spiral blades settles with the screw pile blades,while when the pitch is large,the ability of the spiral blades to restrain the soil decreases,and the soil changes gradually from the inner diameter to the periphery.Using the improved formula to calculate the vertical bearing capacity of single pile can effectively estimate the design value of single pile bearing capacity in engineering practice.

关 键 词：多年冻土区 连续叶片螺旋桩 竖向承载力 模型试验 承载力设计 

分 类 号：TU473.11[建筑科学—结构工程]