Effect of bar shape on the pull-out capacity of fully-grouted rockbolts

KİLİC A., YASAR E., Atis C. D.

TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY, vol.18, no.1, pp.1-6, 2003 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 18 Issue: 1
  • Publication Date: 2003
  • Doi Number: 10.1016/s0886-7798(02)00077-9
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1-6
  • Keywords: rock bolt, bolt shape, pull-out load, bolt failure mechanism, bolt load capacity, BOND STRENGTH, CABLE BOLTS
  • Erciyes University Affiliated: No


This paper presents experimental results obtained from the direct pull-out test using different types of rockbolts having different shape of lugs. These are smooth surface bars, ribbed bars, single conical lugged bars, double conical lugged bars and triple conical lugged bars. It is found that the failure mechanism of the conical lugged rock bolt is different from that of conventional rockbolts, in which the adhesion or the shear strength at the bolt-grout interface provides the load bearing capacity. From the results of experimental study, the use of the conical lugged rock bolts is suggested, because it provides a greater anchorage strength due to wedging effect that is a combination of the shear and compressive strength of the grouting material. (C) 2003 Elsevier Science Ltd. All rights reserved.