坚硬岩地基锚杆抗拔承载机制及破坏模式分析

丁士君; 杨文智; 朱照清; 袁驰

doi:10.13204/j.gyjzG22060608

坚硬岩地基锚杆抗拔承载机制及破坏模式分析

doi: 10.13204/j.gyjzG22060608

1. 中国电力科学研究院有限公司, 北京 100055;
2. 北京工业大学城市建设学部, 北京 100124

详细信息

作者简介:
丁士君,男,1978年出生,博士,正高级工程师。电子信箱:acmilan03@126.com

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出版历程
- 收稿日期: 2022-06-06
- 网络出版日期: 2023-10-17

Analysis on Uplift Bearing Mechanisms and Failure Modes of Anchor Bolts in Hard Rock Foundation

1. China Electric Power Research Institute, Beijing 100055, China;
2. Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China

摘要

摘要: 为研究岩石锚杆基础的抗拔承载机制及破坏模式，考虑锚杆埋深、孔径及混凝土养护龄期的影响，选用硬质花岗岩场地进行了24个原位锚杆载荷试验，采用分布式光纤传感技术对其中7个试验应变进行了测试，分析锚杆上拔荷载传递机理、承载性能影响因素及破坏模式和特征，得到以下结论：孔径大、埋置深的岩石锚杆上拔荷载与位移曲线表现为硬化型，破坏形式主要为锚筋屈服；浅埋、小直径的岩石锚杆上拔荷载-位移曲线大多为软化型，破坏主要发生在锚筋与混凝土界面、锚杆与岩体界面及浅基的基岩中，为剪切复合破坏形式。有效锚固深度小于1.6 m、锚筋与细石混凝土间黏结强度均值为2.82 MPa、混凝土与花岗岩界面抗剪强度不小于1.89 MPa的锚杆，极限抗拔承载力受临界深径比影响显著，而混凝土养护龄期大于5 d后，混凝土对锚固性能影响不明显。
- 坚硬岩 /
- 岩石锚杆 /
- 抗拔承载特性 /
- 破坏模式
Abstract: To study the uplift bearing mechanisms and failure modes of anchor bolt foundations in rock, considering the influence of buried depths and diameters of anchor bolts, and concrete curing ages, 24 anchor bolt loading tests in the field were conducted on hard granite sites. By distributed optical fiber sensing technology, strain tests were performed on 7 anchor bolts of those specimens, the load transfer mechanisms, load-bearing performance influencing factors, and failure modes and characteristics of the anchor bolts were analyzed. To anchor bolts with large diameters and deep embedded depths in rock foundation, the curves between uplift forces and displacements appeared a hardening trend, the failure mode was mainly the yielding of anchor bars. To anchor bolts with small diameters and shallow embedded depths in rock foundation, the curves between uplift forces and displacements of anchor bolts were a softening type, and the failure mainly occurred in interfaces between anchor bars and concrete, between anchor bolts and the rock masses and in shallow bedrock, they were mainly shear composite failure. To anchor bolts in rock, whose the effective anchor depth was less than 1.6 m, the mean bond strength between anchor bars and fine aggregate concrete was 2.82 MPa, and the shear strength of the interface between concrete and hard granite was not less than 1.89 MPa, the ultimate uplift bearing capacity was significantly influenced by the critical depth-to-diameter ratio, however the concrete cured more than 5 days had a little influence on the ultimate uplift bearing capacity.
- hard rock foundation /
- anchor bolt in rock /
- uplift resistance characteristics /
- failure mode

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