Geosciences, Vol. 15, Pages 293: Optimizing Rock Bolt Support for Large Underground Structures Using 3D DFN-DEM Method

Geosciences doi: 10.3390/geosciences15080293

Authors:
Nooshin Senemarian Isfahani
Amin Azhari
Hem B. Motra
Hamid Hashemalhoseini
Mohammadreza Hajian Hosseinabadi
Alireza Baghbanan
Mohsen Bazargan

A systematic sensitivity analysis using three-dimensional discrete element models with discrete fracture networks (DEM-DFN) was conducted to evaluate underground excavation support in jointed rock masses at the CLAB2 site in Southeastern Sweden. The site features a joint network comprising six distinct joint sets, each with unique geometrical properties. The study examined 10 DFNs and 19 rock bolt patterns, both conventional and unconventional. It covered 200 scenarios, including 10 unsupported and 190 supported cases. Technical and economic criteria for stability were assessed for each support system. The results indicated that increasing rock bolt length enhances stability up to a certain point. However, multi-length rock bolt patterns with similar consumption can yield significantly different stability outcomes. Notably, the arrangement and properties of rock bolts are crucial for stability, particularly in blocks between bolting sections. These blocks remain interlocked in unsupported areas due to the induced pressure from supported sections. Although equal-length rock bolt patterns are commonly used, the analysis revealed that triple-length rock bolts (3, 6, and 9 m) provided the most effective support across all ten DFN scenarios.

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Nooshin Senemarian Isfahani www.mdpi.com