摘要
为研究强风化片麻岩中微型抗拔桩的锚固机理及破坏机制,采用准分布电阻应变传感器测试技术,实时监测现场极限抗拔试验过程中微型抗拔桩的应变变化,明确微型抗拔桩的荷载传递规律和分布特征,揭示嵌岩微型抗拔桩的黏结破坏机制。研究结果表明:微型抗拔桩均发生锚筋屈服破坏,MPⅡ(三筋微型抗拔桩)的极限抗拔承载力比MPⅠ(单筋微型抗拔桩)的极限抗拔承载力小3倍,说明MPⅡ内各筋材之间存在群锚效应;微型抗拔桩的锚筋轴力呈单峰型,且轴力沿锚固深度迅速衰减,锚筋轴力主要分布在3 m以内的岩层;锚筋剪应力呈快速增大后减速减小的分布形式,剪应力峰值出现在距孔口0.75 m处。微型抗拔桩锚筋-灌浆体界面、灌浆体-岩土体界面的黏结强度均比现行《岩土锚杆与喷射混凝土支护工程技术规范》(GB 50086-2015)的建议值低。
In order to study the anchorage mechanism and failure mechanism of micro anti-floating pile in heavily weathered gneiss,the quasi-distributed resistance strain sensor test technology was used to monitor the strain changes of micro anti-floating pile in real time during the field ultimate pull-out test,identify the load transfer law and distribution characteristics of micro anti-floating pile,and reveal the bond failure mechanism of rock-socketed micro anti-floating pile.The results show that the ultimate pulling capacity of MPⅡ(three-bar micro anti-floating pile)is 3 times less than that of MP I(single-bar micro anti-floating pile),indicating that there is group anchoring effect among the reinforcement in MPⅡ.The axial force of the anchor bar is unimodal,and the axial force decreases rapidly along the anchoring depth.The axial force of the anchor bar is mainly distributed in the rock layer within 3 m.The shear stress of the anchor bar increases rapidly and then decelerates and decreases.The peak value of shear stress appears at 0.75 m away from the opening.The bond strength of the interface between anchorage and grouting and the interface between grouting and rock and soil is lower than the recommended value in the current technical code for engineering of ground anchorages and shotcrete support(GB 50086-2015).
作者
刘一鸿
白晓宇
闫楠
孙淦
刘俊伟
王永洪
LIU Yihong;BAI Xiaoyu;YAN Nan;SUN Gan;LIU Junwei;WANG Yonghong(School of Civil Engineering,Qingdao University of Technology,Qingdao 266520,China;Key Laboratory of Geological Safety of Coastal Urban Underground Space,Ministry of Natural Resources,Qingdao 266000,China)
出处
《中南大学学报(自然科学版)》
北大核心
2025年第1期297-308,共12页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(52478348)
青岛市自然科学基金原创探索项目(24-4-4-zrjj-180-jch)
山东省泰山学者项目(tsqn202306234)
自然资源部滨海城市地下空间地质安全重点实验室开放基金重点课题(BHKF2021Z09)。
关键词
微型抗拔桩
极限抗拔试验
轴力
剪应力
界面黏结强度
破坏机理
micro anti-floating pile
ultimate pullout test
axial force
shear stress
interfacial bond strength
failure mechanism
作者简介
通信作者:闫楠,博士,副教授,硕士生导师,从事环境岩土工程与基础工程领域的研究工作,E-mail:yannan0527@163.com。
