深部煤层底板岩体能量演化特征及卸荷劣化破坏机制研究  

Study on energy evolution characteristics and unloading degradation failure mechanism of deep coal seam floor rock mass

作　　者：张风达 ZHANG Fengda(CCTEG Coal Mining Research Institute,Beijing 100013,China;Coal Mining and Designing Department,Tiandi Science and Technology Co Ltd,Beijing 100013,China;Coal Mining and Designing Branch,China Coal Research Institute,Beijing 100013,China)

机构地区：[1]中煤科工开采研究院有限公司,北京100013 [2]天地科技股份有限公司开采设计事业部,北京100013 [3]煤炭科学研究总院开采研究分院,北京100013

出　　处：《采矿与安全工程学报》2023年第2期346-353,共8页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(51704158);天地科技股份有限公司开采事业部科技创新基金项目(KJ-2019-TDKCMS-02,KJ-2021-KCMS-06);天地科技股份有限公司科技创新创业资金专项项目(2020-TD-QN007)。

摘　　要：为研究深部煤炭回采过程中底板岩体能量变化特征及卸荷劣化机制,开展了不同围压卸载速率下岩石力学试验,综合理论分析和实验室试验分析了不同卸载阶段的岩石损伤断裂能量、弹性模量的变化特征。研究表明:卸围压过程中的岩石变形破坏可划分为围压卸载起始点至失稳破坏、失稳破坏到加速破坏、进入加速破坏3个阶段。在围压卸载起始点至失稳破坏阶段和失稳破坏到加速破坏阶段,相同轴压下,不同围压卸载速率对岩石弹性模量劣化程度产生的影响较小;在围压卸载起始点至失稳破坏阶段,损伤断裂能量消耗较少,但岩石弹性模量劣化程度较为明显;在失稳破坏到加速破坏阶段,弹性模量的劣化程度相比于围压卸载起始点至失稳破坏阶段趋缓,但损伤断裂能量消耗呈现增长变化趋势。在岩石进入加速破坏阶段,卸载速率越快,岩石卸围压过程中释放的损伤断裂能量越大,越易形成宏观贯穿式裂纹,煤层底板突水危险性随之增大。In order to study the energy characteristics and unloading degradation mechanism of floor rock mass during deep coal mining,rock mechanics tests under different confining pressure unloading rates were carried out.The characteristics of rock damage fracture energy and elastic modulus at different unloading stages were analyzed by comprehensive theoretical analysis and laboratory tests.According to the analysis results,the deformation and failure of rock in the process of confining pressure unloading can be divided into three stages:from the starting point of confining pressure unloading to instability failure,from instability failure to accelerated failure,and into accelerated failure.Under the same axial pressure,different confining pressure unloading rates had little effect on the degradation degree of rock elastic modulus from the starting point of confining pressure unloading to instability failure stage and from instability failure to accelerated failure stage. From the starting point of confining pressure unloadingto instability failure stage,the energy consumption of damage and fracture was less,but the rock elasticmodulus obviously deteriorated. In the stage of instability failure to accelerated failure,the degradation degreeof elastic modulus was slower than that from the starting point of confining pressure unloading to instabilityfailure stage,but the energy consumption of damage and fracture showed an increasing trend.When the rock entered the accelerated failure stage,the energy consumption of damage and fracture increasedwith the increase of confining pressure unloading rate,and the macroscopic penetrating cracks ofcoal seam floor was easy to form,which increased the risk of water inrush in deep mining.

关 键 词：卸荷劣化 损伤断裂 弹性模量 能量 

分 类 号：TD745[矿业工程—矿井通风与安全]