Han Wenmei, Chen Zhaoying, Liu Hongtai, Zheng Xiang, Wu Jinwen, Yuan Qi
Department of Engineering Mechanics, North University of China, Taiyuan, 030051, China.
State Key Laboratory of Coal and CBM Co-Mining, Jincheng, 048012, China.
Sci Rep. 2024 Feb 26;14(1):4593. doi: 10.1038/s41598-024-55361-6.
In sulphur-coal symbiotic coal seams, after the mining of sulphide iron ore, when the coal resources are mined, the mine water accumulated in the roadway mining area will have a certain impact on the stability of the surrounding rock of the coal seam roadway. Taking the floor sandstone of sulfur coal symbiotic coal seam as the research object, the roof fissure water with pH values of 7.48, 4.81 and 2.62 was used as the experimental solution. 10 experimental schemes were designed to measure the compressive strength of the samples under the action of AMD, and the hydrochemical analysis of AMD was conducted. The pore structures of the samples before and after the action of AMD were analyzed. Based on the hydrochemistry and pore structure, the deterioration mechanism of compressive strength of the coal seam floor sandstone under the action of AMD was explained. The results indicated that the compressive strength of the samples decreased with the increasing action time of AMD. The compressive strength decreased with the increment of the porosity. The concentration of H ion in AMD was relatively small. NaO in albite dissolved and reacted with water, leading to an increase in the concentration of Na ion. Soluble substances such as MgCl and CaSO in the pore structure dissolved, leading to an increase in the concentration of Ca and Mg ions. The dissolution of soluble substances and the physical-chemical reactions between solutions and minerals were the essential causes of the continuous deterioration of the compressive strength of the coal seam floor sandstone. The results of this study can provide a theoretical basis for the deterioration of the mechanical properties of the peripheral rock in the roadway of the sulphur coal seam, and can also provide a certain engineering reference for the sulphur coal seam roadway.
在硫煤共生煤层中，硫化铁矿石开采后，开采煤炭资源时，巷道采区积聚的矿井水会对煤层巷道围岩稳定性产生一定影响。以硫煤共生煤层的底板砂岩为研究对象，将pH值分别为7.48、4.81和2.62的顶板裂隙水作为试验溶液。设计了10个试验方案，测定了酸性矿山废水作用下样品的抗压强度，并对酸性矿山废水进行了水化学分析。分析了酸性矿山废水作用前后样品的孔隙结构。基于水化学和孔隙结构，解释了酸性矿山废水作用下煤层底板砂岩抗压强度的劣化机理。结果表明，样品的抗压强度随酸性矿山废水作用时间的增加而降低。抗压强度随孔隙率的增加而降低。酸性矿山废水中H离子浓度相对较小。钠长石中的NaO溶解并与水反应，导致Na离子浓度增加。孔隙结构中的MgCl和CaSO等可溶性物质溶解，导致Ca和Mg离子浓度增加。可溶性物质的溶解以及溶液与矿物之间的物理化学反应是煤层底板砂岩抗压强度持续劣化的根本原因。本研究结果可为硫煤层巷道围岩力学性能劣化提供理论依据，也可为硫煤层巷道提供一定的工程参考。
