摘要
为研究水岩作用下煤岩组合体力学行为及其界面不均匀破坏特征,揭示井下隔水煤岩柱变形及富水环境下煤岩层变形规律.对不同高度比例的岩-煤-岩组合体开展干燥和饱水条件下单轴压缩试验,分析组合体应力-应变、强度及弹性模量劣化规律,探究水岩作用下煤-岩交接面处应力分布关系,明确组合体变形破坏特征及过程.研究结果表明:水岩作用下煤体高度对组合体力学特征具有较大影响,在干燥与饱水状态下,组合体单轴抗压强度与弹性模量均随煤体高度的增加而减小,且试件的破坏形态随着煤体高度的增加由拉伸破坏转变成斜面剪切破坏,最终表现为煤体挤裂破坏.但组合体强度损失劣化度随着岩体层间煤体高度增加,先增大后减小,当煤∶岩高度比为1∶2时,组合体强度对水的敏感度最大并出现极大值,这主要与煤岩交界面高度位置有关.弹性模量呈现降速缓释趋势,主要与组合体组成岩石性质有关.水岩作用下煤体部分为组合体整体失稳破坏的触发点位,延续影响煤体两端岩体,由于交界面产生侧向平面约束力,使煤体轴向抵抗变形能力得到强化,但随着煤体高度的增加,煤体中部所受约束影响迅速衰减.组合体变形破坏渐进性过程分为四个阶段:裂隙孔隙压密阶段、裂隙产生并稳定发育阶段、裂隙加速发育并贯通阶段和破坏后阶段.
This study examines the mechanical behavior and uneven interface damage of coal-rock formations under water-rock interactions,aiming to reveal deformation patterns of coal-rock columns in water-rich environments.This research lays the groundwork for assessing water-related hazards in underground coal mines.Uniaxial compression tests on rock-coal-rock composite specimens,with varying height ratios,were conducted under both dry and saturated conditions.Analysis focused on the stress-strain relationships,strength,and elastic modulus degradation of the composite specimens.The study clarifies stress distribution at the coal-rock interface under water-rock interactions and outlines deformation and failure characteristics.Results indicate that the height of the coal body significantly influences the mechanical properties of the composite under water-rock interactions.Under both dry and saturated conditions,the uniaxial compressive strength and elastic modulus of the composite decrease as the coal body height increases.With increasing coal height,the failure mode transitions from tensile to oblique shear failure,ultimately leading to coal body extrusion failure.However,strength deterioration shows peak sensitivity to water when the coal height is twice that of the rock,mainly due to the height position of the coal-rock interface.The elastic modulus shows a gradual decreasing trend,mainly related to the rock properties within the composite.Under water-rock interactions,the coal body acts as a trigger point for the overall instability and failure of the composite,impacting both rock body ends.The lateral plane constraint force at the interface enhances the axial deformation resistance of the coal body but diminishes rapidly with increasing coal height.The composite progressive deformation and failure process is categorized into four stages:crack-pore compaction,crack initiation,and stable development,accelerated crack development and penetration,and the post-failure stage.
作者
张博成
吴斌斌
杨逾
ZHANG Bocheng;WU Binbin;YANG Yu(CHN Energy Shendong Coal Group Co.Ltd.,Ordos 017000,Inner Mongolia Autonomous Region China;Shendong Coal Branch,China Shenhua Energy Co.Ltd.,Yulin 719000,Shaanxi China;School of Civil Engineering,Liaoning Technical University,Fuxin 123000,Liaoning China)
出处
《河南科学》
2024年第1期55-61,共7页
Henan Science
基金
国家重点研发计划资助项目(2018YFC0604705)
国家自然科学基金资助项目(51774167)
辽宁省重点实验室资助项目(LJZS002)。
关键词
水岩作用
煤岩组合体
强度劣化
力学行为
裂隙演化
water-rock interactions
coal-rock composite
strength deterioration
mechanical behavior
crack evolution
