Influence of fracturing spacing on rock mass fracturing and energy evolution in overlying strata

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2025-08-14 DOI:10.1016/j.tafmec.2025.105174

Rui Gao , Bingqi Xu , Dou Bai , Guorui Feng , Ming Li

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引用次数: 0

Abstract

In the mining of extra-thick coal seam with hard roof, the large roof fracture step and high strength are prone to cause dynamic disasters in the stope. Ground fracturing technology can form an artificial large-scale fracture network in the hard roof to weaken the rock mass fracture strength, which is an innovative and effective technical to control the dynamic disasters. Combining laboratory test and numerical simulation, this paper systematically studied the regulation mechanism of different ground fracturing spacings on the rock fracture mechanical behavior and energy evolution of overburden. Uniaxial compression tests on sandstone specimens with prefabricated cracks, combined with DIC-based crack propagation monitoring, revealed how fracture spacing governs rock mass strength, brittleness indices, and failure mechanisms. The research shows that prefabricated cracks significantly reduce rock mass compressive strength and brittleness indices, with peak strength reduction occurring at 20 mm double-fracture spacing and 5 mm triple-fracture spacing. Based on the coupled model of FLAC^3D and PFC^3D, the internal correlation between fracturing spacing and overburden energy evolution was revealed. Ground fracturing changes the energy release form to energy-damp and energy-slip dissipation by reducing the fracture step of the hard roof. When ground fracturing spacings at 30 m and 10 m, the increment of energy-body in the hard roof was reduced by more than 26 %, the energy accumulation in the hard roof was significantly weakened, and the dynamic disasters in the working face can be significantly prevented and controlled.

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压裂间距对岩体破裂及上覆地层能量演化的影响

在硬顶板特厚煤层开采中，顶板断裂步长大、强度高，容易造成采场动力灾害。地面压裂技术可在硬顶板内人工形成大规模裂缝网络，削弱岩体断裂强度，是一种创新有效的动力灾害控制技术。结合室内试验和数值模拟，系统研究了不同地面压裂间距对覆岩破裂力学行为和能量演化的调节机理。对预制裂缝砂岩试件进行单轴压缩试验，结合基于dic的裂缝扩展监测，揭示了裂缝间距对岩体强度、脆性指标和破坏机制的影响。研究表明，预制裂缝显著降低了岩体抗压强度和脆性指标，强度降低峰值出现在双缝间距20 mm和三缝间距5 mm处。基于FLAC3D和PFC3D的耦合模型，揭示了压裂间距与上覆岩层能量演化之间的内在关联。地面压裂通过减小硬顶板的断裂台阶，将能量释放形式转变为能量阻尼和能量滑移耗散。当压裂间距为30 m和10 m时，硬顶板能量体增量减小26%以上，明显减弱了硬顶板能量积累，对工作面动力灾害有明显的防治作用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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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.