Caving Mechanism and Treatment Method of Overlying Rock in Adjacent Goaf Disturbed by Ore Pillar

doi:10.12068/j.issn.1005-3026.2025.20240069

Abstract

Abstract:

The ore pillar between adjacent goaf usually accumulates a large amount of energy， and the ore pillar instability will lead to large-scale caving hazard accidents. Therefore， a caving-induced mechanical model of goaf was constructed. The caving characteristics and mechanism of the overlying rock in the adjacent goaf were studied through physical experiments and numerical simulation， and a new method of caving induced by ore pillar treatment of the adjacent goaf was proposed. The results show that the existence of the ore pillar can carry a certain amount of energy accumulation， so that the overlying rock above the ore pillar is deformed and destroyed to a certain extent. After the ore pillar is removed， caving of the upper rock mass occurs， and the caving block is small as a whole； it is not easy to induce large-scale overall caving， which can avoid the impact gas wave disaster. The repeated formation and dissipation of stress arches make the overlying strata of the goaf appear intermittent caving， and the development and connection of tensile damage in the overlying strata of goaf are the main reasons for the fracture development and caving of the overlying rock. Engineering practice has shown that this method is characterized by safety and low cost and can provide guidance and reference for the management of goaf under similar conditions.

Key words: adjacent goaf, induced caving, caving mechanism, ore pillar, critical caving span

CLC Number:

TD 853

Jian-li CAO, Feng-yu REN, Dong-jie ZHANG. Caving Mechanism and Treatment Method of Overlying Rock in Adjacent Goaf Disturbed by Ore Pillar[J]. Journal of Northeastern University(Natural Science), 2025, 46(10): 123-131.

Figures/Tables 15

Fig.1 Schematic diagram of adjacent goaf

Fig.2 Force diagram of goaf

Fig.3 Similar simulation experiment model

Table 1 Ratio scheme of similar materials（mass fraction）

河砂	石膏	水泥	松香溶液	水	云母片
80	15	5	2	13	1.3

Fig.4 Excavation process of scheme I

Fig.5 Excavation process of scheme Ⅱ

Fig.6 Strain evolution curves of two experimental schemes

Fig.7 Final caving patterns of two schemes

Fig.8 Distribution pattern of goaf in stope 208 of Shujigou iron mine

Table 2 Mechanical parameters of rock mass

岩石类型	均匀性指数	弹性模量	抗压强度	抗拉强度	泊松比	摩擦角	密度
岩石类型	m	GPa	MPa	MPa	泊松比	(°)	kg·m^-3
磁铁石英岩	3	23	24.1	2.8	0.27	38.5	2 700
斜长角闪岩	3	22	21.4	2.5	0.27	35.7	3 050
节理	5	1	5.5	0.1	0.32	30.3	1 000

Fig.9 Numerical analysis model

Fig.10 Numerical simulation results with ore pillar support

Fig.11 Numerical simulation results of caving of overlying rock without ore pillar support

Fig.12 Numerical simulation results of surface penetration of overlying rock without ore pillar support

Fig.13 Layout of 1 195 m section induction engineering

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