As a typical disaster-causing geological structure, karst collapse pillar (KCP) is widely distributed in coalfields of northern China. The interior of KCP is filled with loose and weakly cemented rock masses. Fine particles can be eroded under the hydraulic pressure and the disturbance of the coal mining operation. Then, water inrush pathway can be formed easily, resulting in water inrush hazard. The release of untreated coal mine water can pollute the environment and waste the limited water resource in China. To investigate the particle erosion effect on the water inrush mechanism of KCP, FLAC3D numerical investigations were conducted to simulate the water flow process of KCP in the mining floor during the coal seam excavation, according to the stress-seepage coupling model with the consideration of the particle erosion. Besides, the evolution of shear stress field, seepage field, and plastic zone along was obtained as working plane advances. Meanwhile, the influence of the thickness of a waterproof rock floor and the hydraulic pressure of aquifer on the formation of water inrush pathway was analyzed. Numerical results indicated that: (1) Shear failure of the KCP near the side of the working plane occurs under the effect of mining excavation; then, the KCP connects with the damage area around the working plane; finally, the water inrush pathway is formed. (2) Water inrush disaster will not occur immediately when the KCP is connected with the damaged area around the working plane; it only occurs when the KCP is completely exposed in the mining. (3) With the mining advances, the thinner the waterproof rock floor and the greater the hydraulic pressure of the aquifer, the easier the groundwater can lead up, and the KCP tends to be damaged with the formation of water inrush pathway.
#1Dan Ma(CUMT: China University of Mining and Technology)H-Index: 26
#2Hongyu Duan(CSU: Central South University)H-Index: 6
Last. Zilong Zhou(CSU: Central South University)H-Index: 28
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Abstract Gangue, produced from coal mining and washing process, is a serious threat to the ground environment. Gangue backfilling mining method can solve this problem and reduce mining-induced hazards, e.g., controlling surface subsidence and preventing water inrush from seeping into goaf by cracks in overlying strata. In this paper, effects of the original particle size distribution (PSD) and water content on the particle crushing behavior and seepage properties of granular gangues were investi...
#1Zilong Zhou(CSU: Central South University)H-Index: 28
#2Xin Cai(CSU: Central South University)H-Index: 19
Last. Haizhi Zang(CSU: Central South University)H-Index: 6
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Abstract To understand combined effects of water saturation and loading rate on the fracture behavior of rock materials, dynamic notched semi-circular bending (NSCB) tests were conducted on dry and saturated sandstone specimens under a wide range of loading rates using a modified split Hopkinson pressure bar (SHPB) setup. Test results revealed that, the dynamic fracture initiation, propagation toughness and crack propagation velocity of saturated specimen were apparently lower than that of dry o...
Abstract Groundwater inrush during excavation is one of the greatest challenges in modern underground engineering. The characteristics of groundwater inrush induced by high-pressure water in fractured rocks are poorly understood, and the risk assessment of water inrush hazard associated with deep geological conditions remains to be improved. Here, we present an in situ high-pressure fluid injection experimental investigation of the hydraulic properties of deep natural fractured rocks. We observe...
#1Zilong Zhou(CSU: Central South University)H-Index: 28
#2Xin Cai(CSU: Central South University)H-Index: 19
Last. Lihai Tan(CSU: Central South University)H-Index: 4
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Abstract Rocks are commonly used as building stone and construction materials in many engineering applications. They usually undergo cyclic wetting and drying processes due to the periodical variations in moist conditions. In this paper, to understand the deterioration on the tensile strength of sandstone induced by wetting and drying cycles, dynamic Brazilian disc tests were conducted on sandstone specimens after every 10 cycles (for a total of 50 cycles) under a wide range of loading rates usi...
Groundwater inrush is a typical hydrologic natural hazard in mining engineering. Since 2000 to 2012, there have been 1110 types of mine groundwater inrush hazards with 4444 miners died or missing. As a general geological structure in the northern China coalfields, the karst collapse pillar (KCP) contains a significant amount of granular rocks, which can be easily migrated under high hydraulic pressure. Therefore, the KCP zone acts as an important groundwater inrush pathway in underground mining....
Karst collapse columns (KCCs) are naturally formed geological structures that are widely observed in North China. Given their influence on normal mining operations and the progress of mining work, collapse columns pose a hidden danger in coal mining under the influence of manual mining. By communicating often with the aquifer, the water inrush from KCCs poses a serious threat to construction projects. This paper adopts three flow field models, namely, Darcy aquifer laminar flow, Forchheimer flow...
When the collapse column and its adjacent rocks in complex geological structures are disturbed by mining, concomitant fine particle migration, mass loss, and porous structure variation during the water seepage process in broken rocks are the inherent causes for collapse column activation and water inrush. Studying the time-varying characteristics of the mass-loss rate in the dynamic seepage system of the broken rocks is of theoretical importance for the prevention of water inrush from the collap...
#1Bing Wang(CSU: Central South University)H-Index: 11
#2Chao Wu(CSU: Central South University)H-Index: 13
Last. Lang Huang(CSU: Central South University)H-Index: 10
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Abstract The problem of work safety greatly affects many parts of the world, especially developing countries such as China. The release of the Thirteenth Five-Year Guideline for National Economic and Social Development in March 2016 marked the beginning of China’s Thirteenth Five-Year Plan (13th FYP) period (2016–2020). Work safety continues to be a national priority. Since the release, a newly important work safety policy, namely the 13th FYP for Work Safety has been announced on February 3, 20...
#1Ke Xu(Xi'an University of Science and Technology)H-Index: 1
#2Gelian Dai(Xi'an University of Science and Technology)H-Index: 2
Last. Xiaoyuan Xue(Xi'an University of Science and Technology)H-Index: 2
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Statistical analysis was used to study the hydrogeochemical evolution of an Ordovician limestone aquifer group in the Hancheng mining area. Before mining, the groundwater flowed from northwest to southeast, the water type was primarily SO4–HCO3, and was mainly controlled by the tectonic structure and the specific hydrogeological conditions. After 40 years of mining, two large groundwater depression cones had formed, centered on the Sangshuping and Xiangshan coal mines in the north and south zone...
Although the impact of Karst Collapse Pillars (KCPs) on water inrush has been widely recognized and studied, few have investigated the fluid-solid interaction, the particles migration inside KCPs, and the evolution feature of water inrush channels. Moreover, an effective approach to reliably predict the water inrush time has yet to be developed. In this work, a suite of fully coupled governing equations considering the processes of water flow, fracture erosion, and the change of rock permeabilit...
#1Li Chong(CUMT: China University of Mining and Technology)
#2He Sifeng(CUMT: China University of Mining and Technology)
Last. Xu Zhijun(CUMT: China University of Mining and Technology)
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The overrunning disaster of harmful gas tends to occur in the working face in thick coal seam with high gas concentration, as the fully mechanized caving stope has the characteristics of high mining intensity, high remnant coal, and high gas content. Therefore, the disastrous mechanism and concentration distribution of gas migration in fully mechanized caving stope are the theoretical basis for gas control scheme. Based on the 7607 working face in Wuyang coal mine, the gas emission quantity in w...
#1Du Yanhui(SDUST: Shandong University of Science and Technology)H-Index: 3
#2Weitao Liu(SDUST: Shandong University of Science and Technology)H-Index: 5
Last. Mengke Han(SDUST: Shandong University of Science and Technology)
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Hidden faults in deep coal seam floor threaten the exploitation of coal resources. Under the influence of mining and water confined in the floor, the cemented filler in the hidden fault will be eroded by water flow, in order to investigate the fracture characteristics and water inrush risk of hidden faults in floors above confined aquifer. Using the 27305 working face as geological background, the influence of the seepage scouring filler on the mechanism of water inrush from hidden faults was as...
#1Mingkun Pang(Xi'an University of Science and Technology)
#1Mingkun Pang(Xi'an University of Science and Technology)
Last. Lei Zhang(Xi'an University of Science and Technology)H-Index: 7
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The initiation process of the mine water inrush accident, the essence of this process is the sudden change of the seepage state of the broken coal medium under pressure and the instability of the skeleton. In order to study the re-crushing mechanism and seepage characteristics of the broken coal medium under load, a set of three-axis seepage system was designed independently. Using the steady-state infiltration method, multiple flow factors under different particle size combinations and differen...
Based on the newly developed sinking headframe for the deep and large shaft, the finite element model of the full-scale headframe was established by using SAP2000. Through the calculation, the theoretical stress of the headframe at sinking depths of 40 m, 143 m, 223 m, 518 m, 762 m, 1000 m, 1250 m, and 1503 m was obtained and then compared with the field measured stress. The results show that with the increase of shaft sinking depth, the theoretical stress of finite element simulation and the fi...
Water inrush from coal seam floors is one major geological obstacle hindering safe and efficient production activities in mines. Determining the source of water inrush can facilitate its prediction and guide decisions regarding measures for prevention and control. The process of identifying the location of hidden hydraulic contact points in different confined aquifers forms the basis of hydrogeological explorations. It is also the basis for categorizing mine areas prone to water inrush and makin...
Abstract The study of flow behaviour of water-sand mixtures in fractured rocks is of great necessity to understand the producing mechanism and prevention of water inrush and sand gushing accidents. A self-developed seepage test system is used in this paper to conduct laboratory experiments in order to study the influence of the particle size distribution, the void ratio, and the initial mass of Aeolian sand on the flow behavior. It is concluded that the water flow velocity is insensitive to the ...
The filling material of the karst collapse column (KCC) is easy to be activated by mining. During this process, the mechanical properties of KCC fillings change, and its water resisting capacity constantly deteriorates and thus often leads to water inrush disaster. In this study, the samples of KCC fillings were taken on-site and then were remolded by the consolidation drainage method. The variation laws of the compressive strength, tensile strength, cohesive stress, internal friction angle, and...
#1Cunli Zhu(CUMT: China University of Mining and Technology)H-Index: 2
#2Jixiong Zhang(CUMT: China University of Mining and Technology)H-Index: 22
Last. Yaben Guo(CUMT: China University of Mining and Technology)
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Sand-based cemented backfill (SBCB) mining technology is instrumental in utilizing coal resources buried under the water bodies. SBCB is exposed to the long-term action of mining-induced stresses in the goaf and groundwater permeating via microcracks along the rock strata. Studying the permeability evolution of SBCB under varying stress states is crucial for protecting coal and water resources below the aquifer. This study is focused on the influence law of different stress states on the SBCB pe...
#1Cun Zhang(CUMT: China University of Mining and Technology)H-Index: 16
#2Fangtian Wang(CUMT: China University of Mining and Technology)H-Index: 12
Last. Qingsheng Bai(Freiberg University of Mining and Technology)H-Index: 1
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Abstract A large number of abandoned mines with sizeable underground space resources were formed in China. Meanwhile, for an operational mine, the protection and utilization of mine water resources are increasingly important for ecological environment construction. The coal industry faces difficulties regarding safe and efficient utilization of abandoned mine resources and protection of the ecological environment in the operational mines. As a solution to these problems, underground water reserv...