Analysis of Interface Stress of Grouting Rockbolt and Calculation of Critical Anchorage Length

doi:10.12068/j.issn.1005-3026.2021.11.014

Abstract

Abstract: To clarify the mechanism of the grouting rockbolt with a semi-infinite anchorage length， the interface mechanical property of the rockbolt was analyzed and the corresponding pull-out equations were present. Assuming that the shear stress distribution of the elastic part of the anchor rod along the anchoring depth was a quarter elliptical arc， and then the calculation formula of the critical anchorage length of the grouting rockbolt was given. To verify the correctness of the present method， in-situ pull-out tests were carried out on 4 anchor rods with anchoring lengths of 6.0m and 8.5m， respectively. The results showed that the axial strain distribution curve calculated by the present method was consistent with the experimental results， and the axial strain decreases nonlinearly with the anchoring depth. The critical anchorage length calculated by the present method was 5.3m， which was 3.6% different from the test result. The method presented in the manuscript was universal， and the calculation results obtained by the present method were relatively conservative compared with the results obtained by previous research.

Key words: rockbolt; grouting; interface stress; critical anchorage length; pull-out test

CLC Number:

TG335.58

ZHANG Yao-sheng， WANG Lian-guang， HUANG Xiao-bin， CHENG Bai-ling. Analysis of Interface Stress of Grouting Rockbolt and Calculation of Critical Anchorage Length[J]. Journal of Northeastern University(Natural Science), 2021, 42(11): 1618-1624.

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