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Seong-Seung Kang [1] and Atsuo Hirata [2] and Bo-An Jang [3] and Yong-Seok Seo [4] and Daehyeon Kim [5]

Academic Editor: Luigi Nicolais

1, Department of Energy and Resources Engineering, Chosun University, Gwangju 61452, Republic of Korea, chosun.ac.kr

2, RS Technology Co., Ltd. and Sojo University, Kumamoto 862-0941, Japan, sojo-u.ac.jp

3, Department of Geophysics, Kangwon National University, Chuncheon 24341, Republic of Korea, kangwon.ac.kr

4, Department of Earth and Environment Sciences, Chungbuk National University, Cheongju 28644, Republic of Korea, chungbuk.ac.kr

5, Department of Civil Engineering, Chosun University, Gwangju 61452, Republic of Korea, chosun.ac.kr

Received Jun 8, 2017; Accepted Jul 17, 2017

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. Introduction

Civil and mining engineering employs various devices for support and reinforcement [1–7]. Examples include ground anchors, which are mainly used for ground reinforcement, and rock and cable bolts that reinforce rock [8, 9]. Supports of various types can restrict the subsequent deformation of the geostructures due to further excavation [10–13].

Eco-spiral bolts have been developed to stabilize geostructures and constructions such as foundation, tunnel, and slope. They are manufactured by repeatedly twisting a steel sheet bar [14–16] and are suitable for use in both soft ground and rock mass due to the high axial resistance force that the ground applies to the bolt. Eco-spiral bolts can be directly installed in soft ground using only a twisting force without drilling. Therefore, the geostructure between the ground and the bolt is not disturbed and installation is quick. Eco-spiral bolts can be installed in hard rock mass in the same way as rock and cable bolts.

This study aims to define the interactions between the eco-spiral bolt and the crushed rock in a borehole by pull-out testing using laboratory test and numerical analysis. For this purpose, the effect of porosity with respect to the different sizes of the eco-spiral bolt and the crushed rock was firstly clarified by laboratory pull-out testing. Secondly, the relationship between the axial resistance force and the displacement was evaluated depending on the different sizes of the eco-spiral bolt and the crushed rock in a borehole. Finally, the maximum principal stress between...

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