急斜煤层顶板裂隙扩展诱导能量时-空演变特征

1.西安科技大学 能源学院,陕西 西安 710054; 2.西安科技大学 陕西省岩层控制重点实验室,陕西 西安 710054; 3.西安科技大学 西部矿井开采及灾害防治教育部重点实验室,陕西 西安 710054; 4.神华新疆能源有限责任公司,新疆 乌鲁木齐 830027

急斜煤层; 裂隙扩展; 释能与迁移; 模拟实验; “声-热”指标

Spatio-temporal evolution mechanism of induced energy with roof-crack propagation in extremely steep coal seams
LAI Xing-ping1,2,3,LIU Jian-ning1,CUI Feng1,LIU Jin-ji4,MENG Ping-yuan1,LIU Hui1,CAO Jian-tao1

(1.College of Energy Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Shaanxi Provincial Key Laboratory of Ground Controlling,Xi'an University of Science and Technology,Xi'an 710054,China; 3.Key Laboratory of Western Mine Exploitation and Hazard Prevention,Ministry of Education,Xi'an University of Science and Technology,Xi'an 710054,China; 4.Shenhua Xinjiang Energy Co.,Ltd.,Urumchi 830027,China)

extremely steep coal seams; crack propagation; release and migration of energy; model experiment; acoustic-heat indicators

DOI: 10.13800/j.cnki.xakjdxxb.2018.0407

备注

水平分段综放开采面顶板断裂失稳预测对急斜煤层开采动力灾害防治至关重要。以碱沟矿495 m水平B1+2煤层综放工作面为背景,基于现场开采条件分析,开展顶板能量演变理论计算,构建急斜煤层顶板裂隙扩展能量演变物理平面模型实验,采用声发射与红外热像综合监测手段,揭示急斜煤层顶板裂隙扩展诱导能量时-空演变特征。研究表明:急斜煤层顶板积储的可释放应变能大于耗散能,采动作用致使顶板岩体内部损伤加剧,裂隙扩展诱导能量释放速率必然骤增; 采动岩体裂隙动态扩展过程中声发射信号与红外热量同时变化,其中声发射事件数与能率呈缓慢与快速演化特征,红外热像出现热量异常(区)迁移; 顶板破裂过程中“声-热”时序演变特征的实质为裂隙扩展诱导能量非均匀释放,形成缓慢与加速释放迁移的时-空演化过程,能量加速释放易造成顶板断裂失稳并诱发动力灾害。这为现场灾害预报与防治提供科学依据。

Prediction methodology for roof instabilityinduced by crack fracturingwith horizontal sectional top-coal caving in extremely steep coal seams is crucially important for the prevention and control of dynamic hazards.Research set fully mechanized caving face of B1+2 coal seam of +495 m level in Jiangou colliery as research area.Spatio-temporal evolution mechanism of induced energy with roof-crack propagation was revealed with hybrid methods including in-situ mining setting analysis,theoretical computation of the energy evolution of the roof and physical simulation of energy evolution with roof-crack propagation,the parameters of physical simulation were recorded with the infrared thermal instruments and AE sensors.The results show that value of released strain energy in the roof is obviously greater than that of dissipation energy.Excavation disturbance increase the damage of rock and the releasing velocity of the strain energy increase remarkably due to roof-crack propagation.The acoustic emission index and infrared heat in the dynamic expansion of crack of mining rock mass are changed simultaneously.The results indicate that AE parameters value composes both slow evolution and rapid evolution.Heat Abnormal Zone(HAZ)emerges from the infrared thermal images and all the images could present the migration phenomena of HAZ.The migratory phenomenon of acoustic-heat indicators is a result by inhomogeneous release of the induced energy with roof-crack propagation.Spatio-temporal migration of the induced energy is divided into slow evolution and rapid evolution,and the roof fracturing-caused instability results in dynamic hazards while the induced energy is in the rapid evolution.The achievement will provide a scientific basis for site hazard prediction and prevention.