Experimental study on fracture behavior of coal-rock samples with varying sandstone strength using the ultrafast time-resolution method

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2025-02-15 DOI:10.1016/j.tafmec.2025.104885

Shankun Zhao , Mingyuan Zhang , Guanghui He , Kun Lv , Dejian Li , Yingjun Li , Hainan Gao

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引用次数: 0

Abstract

The planning and construction of mine roadways inevitably involve crossing interfaces between coal and rock seams. While previous studies have extensively examined the mechanical properties of coal-rock combinations with varying coal and rock seam thicknesses, few research has focused on the fracture behavior of samples with different rock seam strengths. Three-point bending experiments were conducted on coal-rock combined samples with pre-crack and sandstone, which had uniaxial compressive strength of 34.4 MPa and 124.7 MPa, respectively, to analyze their influence on the mechanical properties of the samples. Each combination types featured coal-rock thickness ratios of 1:1, 2:1, and 5:1, respectively. The entire fracture process, from loading to failure, was captured using the ultrafast time-resolution method based on pulsed laser technology, achieving a time resolution of 15 picoseconds. The experimental results revealed distinct failure mechanisms between samples with weak versus strong sandstone seams. The macroscopic cracks in samples with weak sandstone emerged at the peak load, whereas in those with strong sandstone, macroscopic crack occurred prior to peak load. Furthermore, samples with weaker sandstone exhibited progressive failure modes at coal-rock thickness ratios of 2:1 and 5:1, whereas all other groups demonstrated brittle failure. The crack tip locations and mode I stress intensity factors (SIF) at crack initiation were determined using digital image correlation (DIC) in conjunction with the immune algorithm (IA). It is recommended that mine roadways construction account not only for the coal seam thickness-to- roadway height ratio but also for the strength of the overlying rock strata.

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来源期刊

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.