摘要
在浅部煤炭开采等工程中,围岩更易受到覆岩运动、采掘扰动等影响,处于循环加卸载状态,导致力学性能劣化,易诱发次生灾害。为深入理解岩石在复杂应力循环荷载下的力学行为、能量演化及损伤特性,本文以宁夏枣泉煤矿为工程背景,针对其煤层巷道围岩主要岩性(砂岩、泥岩和煤层),开展了单轴压缩及循环加卸载试验。通过系统分析围岩的力学特性、能量演化规律,引入能量视角建立岩石稳定性评价方法。研究结果表明:循环加卸载显著降低了煤层的强度极限(下降50.87%),砂岩次之(下降10.17%),泥岩强度变化较小;泥岩和煤层的弹性模量在循环加载后有所提高,砂岩弹性模量略有降低,表明循环加卸载对不同岩性的力学性能影响存在显著差异,煤层的力学性能劣化最为明显。从能量演化与损伤程度角度出发,砂岩在循环过程中累积耗散能最高,但损伤程度最低(6.17%),反映出其较强的抗疲劳能力;煤层的累积耗散能次之,却具有最高的损伤程度(10.85%),与煤层的脆性指数最高密切相关;泥岩因初始强度低,循环加载后损伤程度相对较高,其脆性指数最低且破坏相对温和。研究为浅部巷道围岩稳定性评估与支护设计提供了理论依据与量化指标,有助于优化巷道支护参数设计,保障矿产开采的安全与高效。
In shallow coal mining projects,the surrounding rock is more susceptible to the movement of overlying strata and mining interference.It is in a cyclic loading-unloading state,which degrades its mechanical properties and easily triggers secondary disasters.To better understand the mechanical behavior,energy evolution,and damage characteristics of rocks under complex cyclic stresses,this paper uses the Zaoquan Coal Mine in Ningxia as a case.It conducts uniaxial compression and cyclic loading-unloading tests on the main lithologies(sandstone,mudstone,and coal seam)of the coal seam roadway surrounding rock.Through systematic analysis of the surrounding rock’s mechanical properties and energy evolution patterns,and by incorporating an energy based perspective,a rock stability evaluation method is established.Results show that cyclic loading-unloading significantly reduces coal seam’s ultimate strength(50.87%drop),followed by sandstone(10.17%drop),with minor changes in mudstone strength.After cyclic loading,the elastic modulus of mudstone and coal seam increases,while that of sandstone slightly decreases,indicating significant differences in mechanical property changes across lithologies,with coal seam showing the most degradation.From the energy evolution and damage degree perspectives,sandstone has the highest cumulative dissipated energy but the lowest damage degree(6.17%),reflecting strong fatigue resistance.Coal seam,despite the second highest cumulative dissipated energy,has the highest damage degree(10.85%),closely related to its high brittleness index.Mudstone,with low initial strength,exhibits a relatively high damage degree after cyclic loading,having the lowest brittleness index and a milder failure mode.This research offers theoretical support and quantitative indicators for stability assessment and support design in shallow roadway surrounding rock.It aids in optimizing roadway support parameters,ensuring safe and efficient mineral extraction.
作者
朱明鎏
马永生
秦广鹏
王思雨
韩凯月
侯心雨
ZHU Mingliu;MA Yongsheng;QIN Guangpeng;WANG Siyu;HAN Kaiyue;HOU Xinyu(Zaoquan Coal Mine,CHN Energy Group Ningxia Coal Industry Co.,Ltd.,Yinchuan 750001,China;College of Resources,Shandong University of Science and Technology,Tai’an 271000,China;National Engineering Research Center for Coal Backfilling Mining,Tai’an 271000,China)
出处
《中国矿业》
北大核心
2025年第S1期360-366,共7页
China Mining Magazine
基金
宁夏自治区重点研发计划项目资助(编号:2023BDE92023)。
关键词
浅埋煤层
循环加卸载
耗散能法
能量演化
损伤程度
shallowly buried coal seam
cyclic loading-unloading
dissipated energy method
energy evolution
damage degree
