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Preliminary Research on Dynamic Hoek–Brown Strength Criterion for Rock Mass.

Authors :
Xie, Xiaokun
Li, Jianchun
Zou, Yang
Li, Xing
Zhao, Jian
Source :
Rock Mechanics & Rock Engineering. Jan2025, Vol. 58 Issue 1, p539-556. 18p.
Publication Year :
2025

Abstract

The Hoek–Brown strength criterion is commonly employed to anticipate rock mass failure, considering influential factors including rock mass quality and static stress conditions. Nevertheless, extensive experiments have revealed that the strength of intact rock also depends on the loading rate. Since rock masses frequently experience dynamic loading in practical scenarios, extending the application of this criterion into the dynamic domain is both valuable and challenging. This paper initiates an exploration into the dynamic strength criterion of rock masses, drawing from experimental studies on the dynamic mechanical response of jointed rock specimens. A dynamic three-dimensional strength test was carried out on artificially jointed rock specimens using SHPB equipment with confining pressure. Specimens contain a set of sub-horizontal joint and a set of sub-vertical joint. The research shows that the dynamic compressive strength and Young's modulus of jointed rock specimens increase with the increase of loading rate. The dynamic scale effect of rocks is more related to the structure, rather than being solely dictated by scale. Discussion is undertaken regarding the fundamental form of dynamic strength criterion of rock mass, which is modified from the Hoek–Brown (H–B) criterion. Subsequently, the dynamic compressive strength and Young's modulus of jointed rock specimens are analyzed. By accounting for dynamic size effects, the geological strength index (GSI) was evaluated, which is closely consistent with GSI calculated through dynamic Young's modulus. The relationship between GSI and loading rate is discussed. According to the GSI chart, the joint spacings of rock masses as reflected by the specimen's structures under different loading rates are derived. These findings contribute valuable guidance on utilizing laboratory-scale jointed rock specimens to assess the mechanical behavior and strength characteristics of rock masses under dynamic loads such as blasting. Highlights: Dynamic experiment on jointed rock specimens using SHPB equipment Dynamic mechanical properties of jointed rock specimens Dynamic Hoek-Brown strength criterion for rock masses Dynamic size effect of jointed rock mass and dynamic GSI [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
07232632
Volume :
58
Issue :
1
Database :
Academic Search Index
Journal :
Rock Mechanics & Rock Engineering
Publication Type :
Academic Journal
Accession number :
182191551
Full Text :
https://doi.org/10.1007/s00603-024-04160-6