砂岩地层变截面桩抗拔承载特性现场试验研究  

Field test study on uplift bearing characteristics of non-uniform cross-section piles in sandstone strata

作　　者：曹以虎 杨柏 孙珍茂[4] 杨晓慧 Cao Yihu;Yang Bai;Sun Zhenmao;Yang Xiaohui(Guangzhou Zhuhai Section of Beijing Zhuhai Expressway Co.,Ltd.,Zhongshan 528441,China;School of Architecture and Transportation Engineering,Guilin University of Electronic Technology,Guilin 541004,China;Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu 610031,China;Sichuan Electric Power Design&Consulting Co.,Ltd.,Chengdu 610016,China)

机构地区：[1]京珠高速公路广珠段有限公司,广东中山528441 [2]桂林电子科技大学建筑与交通工程学院,广西桂林541004 [3]西南交通大学地球科学与环境工程学院,成都610031 [4]四川电力设计咨询有限责任公司,成都610016

出　　处：《工程勘察》2022年第5期1-6,18,共7页Geotechnical Investigation & Surveying

基　　金：国家自然科学基金(42067044)。

摘　　要：为研究砂岩地层变截面桩抗拔承载特性,本文对变截面桩和等截面桩进行了现场静载荷试验,分析比较了两种桩型的侧阻力与轴力作用特征,并将试验结果与规范计算值进行了比较。结果表明:变截面桩的抗拔承载特性与等截面桩相似,其桩身侧阻力值主要受岩土体性质的影响,与桩径无关,但是桩径和桩长的增加能有效提高桩基极限抗拔承载力。受地层变化和应力集中影响,变截面桩桩身变形量增大,桩与岩土体相对位移增大,侧阻力充分发挥,故在变截面处桩身轴力和侧阻力急剧变化。采用规范方法计算变截面桩和等截面桩的极限抗拔承载力,计算值分别为试验值的29.6%~38.8%和29.5%~65.5%,说明规范方法偏于保守。In order to study the uplift bearing characteristics of variable section piles in sandstone stratum,in-situ static loading tests were carried out on non-uniform cross-section piles and uniform cross-section piles.The characteristics of side resistance and axial force of the two type piles were analyzed and compared,and the test results were compared with the calculated values according to the code.The results show that the uplift bearing capacity of the non-uniform cross-section pile is similar to the uniform cross-section pile.The side resistance is unrelated to the pile diameter,which is mainly affected by the properties of surrounding rock and soil.Increasing pile diameter and pile length can effectively improve the ultimate uplift bearing capacity of piles.Due to the effect of stratum change and stress concentration,the pile deformation increasing will result in the relative displacement between pile and rock/soil mass increase,and the side resistance will be fully mobilized.The axial force and side resistance changes sharply in the pile section where the diameter suddenly changes.The ultimate uplift capacity of variable and uniform cross-section piles is calculated according to the code proposed method.The calculated values are about 29.6%~38.8% and 29.5%~65.5% of the test values respectively.It is proved conservative of the code method.

关 键 词：变截面桩 抗拔承载特性 极限抗拔承载力 砂岩地层 现场试验 

分 类 号：TU473.1[建筑科学—结构工程]