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| Research on acoustic emission and fragmentation characteristics of segmented high temperature hard coal under axial static loads |
| WANG Cheng1，LEI Binbin1，WANG Chun1，2，XIONG Zuqiang1，ZHANG Yaohui3，TAN Yi1 |
| (1. School of Energy Science and Engineering，Henan Polytechnic University，Jiaozuo，Henan 454003，China；
2. Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization，Henan Polytechnic University，Jiaozuo，Henan 454003，China；3. Henan College of Industry and Information Technology，Jiaozuo，Henan 454003，China) |
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Abstract 基于深部煤层注热、地下气化、煤层自燃等工程所处的高温、高静载、不均匀受热等环境，以深部硬煤为研究对象，采用自制加热设备加热煤样模拟深部的高温环境，施加轴向静载模拟煤层所受的高静载，开展不同加热长度的分段高温轴向静载声发射试验研究，分析煤体的变形破坏特征。研究结果表明：分段高温处理后的煤样应力–应变曲线可划分为压密、弹性、塑性和破坏4个阶段，且同一加热温度下，加热长度越长，煤样的压密过程越明显；煤样的抗压强度、弹性模量和泊松比随着加热长度的增加出现一定的波动，但整体上来说呈线性趋势减小；轴向压缩过程中没有始终伴随着声发射，且压密、弹性和塑性阶段，声发射的幅值、计数、能量的值较小，一旦进入破坏阶段，声发射参量便产生剧烈波动，且煤样发生宏观破坏时应力曲线跌落，声发射信号随之停止；轴向压缩过程中的声发射累计值从常温到100 ℃高温的变化非常明显，且累计值与常温状态下相比会有不同程度的降低，但在同一温度下，随着加热长度的增加声发射累计值与分段长度并没有明显的规律；对破碎后的煤块进行筛分试验及分形特征分析，发现煤样发生拉伸破坏的同时也伴随着剪切破坏，且分形维数的变化特征和煤样破坏块度的变化规律较一致，能较好的反映煤样破碎特征。
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