摘要
为研究浸水对煤岩特性的影响,提高综放效率,通过选取煤样利用X射线衍射(XRD)和荧光光谱(XRF)测试进行不同浸水时间的煤岩成分分析,并通过超声波测试系统研究了浸水时间对煤岩细观结构演化特征的影响。XRF测试结果表明,随着浸水时间增加,硬质矿物方解石颗粒脱落或溶解于水中,造成其含量下降,从而使高岭石含量呈相对上升趋势。XRD测试结果表明,随着浸水时间的增加,煤体内细颗粒之间的粘结力将进一步减弱,孔隙变大、裂隙变深,水与煤之间的接触范围增大,相互作用更为强烈,如此反复,使得煤体内软弱结构面产生间隙,煤岩强度减弱,增加顶煤冒放性。超声波测试结果表明,随着浸水时间增大,煤样超声波纵波波速显示出先增后减的规律;浸水前期,孔隙逐渐被水分充填,超声波传递能力增强,波速上升;浸水时间达到4d左右,较大孔隙系统已接近吸水饱和,小孔隙吸水时产生的"水楔作用"增大了煤颗粒间距,再加上内部孔隙系统不断发育连通,纵波传播速度下降。该研究可为放顶煤开采现场确定顶煤注水的最佳时间提供理论依据。
In order to study the influence of water immersion on the characteristics of coal and rock and improve the efficiency of caving,the coal rock composition was analyzed by X ray diffraction（ XRD） and fluorescence spectroscopy（ XRF）,and the influence of immersion time on the microstructure evolution characteristics of coal rock was studied by ultrasonic testing system. The results of XRF test show that the content of kaolinite decreases with the increase of the soaking time. The content of calcite particles drops or dissolves in the water,thus the content of kaolinite is on the rise.The results of XRD test show that with the increase of water immersion time,the cohesive force between fine particles in the coal is further weakened,the pores become larger and the cracks become deeper. The contact range between water and coal is increased and the interaction is more intense. This leads to generation of fissures on weak structural surface of coal,the strength of coal and rock is weakened and the top-coal cavability is increased. The ultrasonic testing results show that,as the soaking time increases, the ultrasonic longitudinal wave velocity of the coal sample increases first and then decreases. The pore is gradually filled with water in the early stage of immersion, the transmission capacity of the ultrasonic wave is increased,the velocity of wave is rising,the soaking time reaches about 4 d,the large pore system is saturated with water absorption and the small pore water absorption leads to ＂water wedge＂,which increases the distance between coal particles,and with the continuous development of internal pore system, and the propagation velocity of longitudinal waves decreases. The study can provide theoretical basis for determining the best time for top coal water injection in top-coal caving site.
作者
鲁杰
于浩
宁掌玄
徐青云
LU Jie, YU Hao, NING Zhang-xuan, XU Qing-yun(School of Mining Engineering, Shanxi Datong University, Datong 037006, Chin)
出处
《煤炭工程》
北大核心
2018年第5期118-122,共5页
Coal Engineering
基金
山西大同大学2017年校级科研基金项目(2017K8)
