摘要
煤层倾角突变区是深部煤炭采掘过程中极易发生煤与瓦斯突出的复杂地质条件之一。以河南平顶山某矿为研究对象,开展不同倾角突变条件下突出模拟试验研究,设置倾角突变界面,界面上侧为原煤,下侧为型煤,分别用于模拟原生煤层与构造煤层。定义煤层倾角突变初始角度θ_(I)、突变角度θ_(M)、突变角临界值θ_(T)、瓦斯在倾角突变区集中系数I_(θ),用以分析煤层倾角突变对突出强度造成的影响。引入单位突出强度IU表征试验过程中的突出强弱,期间利用声发射技术对突出过程中能量演化规律进行监测,并通过内置于试样中的温度传感器记录各区域温度的变化情况。研究结果表明:(1)煤层倾角突变区对突出时临界瓦斯压力及单位突出强度具有显著影响,在10°<θ_(I)≤20°、10°≤θ_(M)≤20°范围内存在煤层倾角突变临界值θ_(T),当θ_(I)与θ_(M)均大于等于θ_(T)时,易发生低指标突出;当θ_(I)或θ_(M)一定时,单位突出强度随瓦斯在倾角突变区集中系数增大而增大。(2)煤层倾角突变初始角度θ_(I)及突变角度θ_(M)与声发射能量峰值及累计声发射能量间呈负相关关系,随着θ_(I)与θ_(M)的增大,煤体达到破裂失稳所需能量逐渐降低,当所处地应力环境相同时,其在低瓦斯压力条件下即可发生突出。(3)突出孕育与激发阶段,煤体内部温度变化存在显著差异,煤层倾角突变区附近温度变化明显高于其余各区域,突出口近端区域煤体温度波动较其他区域表现出了更强的不稳定性。
The abrupt change area of coal seam dip is one of the complex geological conditions that significantly increase the risk of coal and gas outburst during deep mining.Using a mine in Pingdingshan,Henan Province,as the research subject,we conducted experimental research to simulate coal and gas outburst under various inclination mutation conditions.An interface with a dip mutation was established,positioning raw coal on the upper side and type coal on the lower side to emulate primary and tectonic coal seams,respectively.The initial angle(θ_(I))of abrupt change in coal seam dip,the abrupt change angle(θ_(M)),the critical value of the abrupt change angle(θ_(I)),and the gas concentration coefficient(I_(θ))in the abrupt change area of coal seam dip were defined.The above parameters were used to analyze the effect of abrupt change in coal seam dip on the intensity of coal and gas outburst.The unit outburst intensity(IU)was introduced to characterize the strength of coal and gas outburst during the test.Acoustic emission technology was employed to monitor the energy evolution pattern during coal and gas outburst,while temperature changes in each area were recorded using sensors embedded in the sample.The findings of the study indicate that:(1)The abrupt change area of coal seam dip significantly impacts on both the critical gas pressure and the unit outburst intensity during coal and gas outburst.There exists a critical value(θ_(T))of the abrupt change angle in coal seam within the range of 10º<θ_(I)≤20º,10º≤θ_(M)≤20º.When bothθ_(I) andθ_(M) exceed or are equal toθ_(T),a low-index coal and gas outburst becomes more likely to occur.Whenθ_(I) orθ_(M) is fixed,the unit outburst intensity in the abrupt change area of coal seam dip increases as the gas concentration coefficient(I_(θ))increases.(2)A negative correlation exists betweenθ_(I) and both the peak and cumulative AE energy.A similar negative correlation exists betweenθ_(M) and both the peak and cumulative AE energy.As bothθ_(I) andθ_(M) increase,the energy required for the coal body to reach rupture and destabilization progressively diminishes.Under identical geostress conditions,this phenomenon facilitates coal and gas outburst even at lower gas pressures.(3)Notable temperature variations occur within the coal body during the incubation and excitation phases of coal and gas outbursts.Temperature changes in the abrupt change area of coal seam dip are significantly higher than in other zones.Temperature fluctuations in the proximal region of the outburst vent show greater instability than in other regions.
作者
唐巨鹏
黄磊
潘一山
任凌冉
张昕
张众华
TANG Ju-peng;HUANG Lei;PAN Yi-shan;REN Ling-ran;ZHANG Xin;ZHANG Zhong-hua(School of Mechanics and Engineering,Liaoning Technical University,Fuxin,Liaoning 123000,China;School of Environmental,Shenyang University,Shenyang,Liaoning 110044,China;Institute of Disaster Rock Mechanics,Liaoning University,Shenyang,Liaoning 110036,China)
出处
《岩土力学》
北大核心
2025年第6期1719-1730,共12页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52374122,No.51874165)
辽宁省“兴辽英才计划”项目(No.XLYC1902106)。
关键词
煤层倾角突变
煤与瓦斯突出
单位突出强度:声发射能量
温度
abrupt change in coal seam dip
coal and gas outburst
unit outburst intensity
acoustic emission energy
temperature
