A numerical study of the behavior of fully grouted rockbolts under dynamic loading |
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| Institution: | 1. School of Mining Engineering, UNSW SYDNEY, NSW, Australia;2. Open Laboratory for Deep Mine Construction, Henan Polytechnic University, Jiaozuo 454033, China;1. State Key Laboratory for Geomechanics and Deep Underground Engineering, Beijing, China;2. China University of Mining and Technology, Beijing, China;3. State Nuclear Electric Power Planning Design & Research Institute CO., LTD, Beijing, China;4. University of Porto, Porto, Portugal;1. School of Civil, Mining and Environmental Engineering, University of Wollongong, Australia;2. Environmental Engineering Urban Water Technology Centre (UWTC), University of Abertay Dundee, Dundee, Scotland;1. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Beijing 100083, China;2. School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China |
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| Abstract: | The widespread preference for rockbolts in providing adequate rock stability in underground mines and man-made cavities make it necessary to obtain a better understanding of the response of these support systems. It is widely accepted that the fully grouted rockbolts provide better roof stability in areas of very poor roof condition which may be caused by high ground stress conditions. There is little information about the in situ behavior of these systems especially under dynamic loading. Hence, to study the behavior of fully grouted rockbolts under dynamic loading, a numerical modeling study was conducted using the FLAC3D code. In this study the behavior of three types of fully grouted rockbolts were compared with each other including rockbolts with and without head plate and a yielding type one. The results of analyses indicated that under dynamic loading the fully grouted rockbolts without the head plate are incapable of controlling the rock mass movement. Although fully grouted rockbolts with head plate damp a considerable amount of the dynamic energy through friction as these bolts slide within the grout, but the elongation of the rockbolt is not possible due to the rapid breakage of the rockbolt–grout interface. Yielding rockbolts are the best choice for the absorption of the dynamic stress wave and controlling of the rock mass movement. The obtained results show that the optimal design of yielding rockbolt should be in such a way that after dynamic loading, anchoring part of bolt has a limited movement to prevent stress concentration in the shaft of rockbolt and its breakage. |
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| Keywords: | Fully grouted rockbolt Numerical modeling Axial stress distribution Dynamic loading |
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