基于数据分析的近直立煤层冲击地压致灾因素研究

Study on factors affecting rock burst of sub-erectcoal seam based on data analysis

为了掌握乌东煤矿南区近直立特厚煤层冲击地压致灾因素,基于矿井采掘布局及B3+6煤层上覆煤柱赋存特征,采用数据统计的方法分别对矿井微震事件分布和B3+6煤层综放工作面冲击地压事故进行了统计分析。研究结果表明:上覆煤柱是冲击地压显现的主要致灾因素,采掘扰动、采深、煤柱资源回采情况是冲击地压显现的影响因素。不同煤层综采和掘进工作面相向80 m、相错110 m时,采掘扰动影响较明显,相向0~30 m时微震频次达到峰值;B3+6煤层冲击地压事故集中分布在大洪沟煤矿小井工业广场煤柱和大洪沟煤矿工业广场煤柱区域,经过多分层开采后,上覆煤柱应力影响作用仍存在,且随煤层开采层数增加,冲击地压显现时工作面的位置与煤柱关系呈“进煤柱前-煤柱下-出煤柱后”规律性变化。发生冲击地压时综放工作面集中分布在距煤柱边界50 m范围内,随着上覆煤柱走向长度增加,冲击地压事故发生时综放工作面与煤柱边界的距离增大,同时煤柱附近区域冲击地压事故的概率和破坏强度也随之增加。

In order to grasp the hazardous factors of rock burst in sub-erect coalseamin the southernpart of Wudong coal mine,based on the mining layout and occurrence characteristics of overlying coal pillars in B3+6 coal seam,the data statistics method is used to separately distribute the mine microseismic events and rock burst accidents in fully-mechanized caving face of B3+6 coal seam.The results show that the overlying coal pillar is the main disaster-causing factor of rock burst,and mining disturbance,mining depth and coal pillar resource recovery are the influencing factors of rock burst.The influence of mining disturbance is obvious when the distance of fully mechanized mining face and the development face of different coal seams during mining is 80 m and when the mining crossing distance is 110 m,and the frequency of microseisms reaches the peak when advancing difference of the two faces is with in 0~30 m.B3+6 coal seam rock burst accidents are concentrated in the pillar area of a small shaft and the industrial square areaof Dahonggou coalmine.After multi-layer mining,the stress effect of overlying coal pillar still exists,and with the increase of the numbers of coal seam mining layers,the relationship between the location of the working face and the coal pillar changed following a regular law as"before the coal pillar-under the coal pillar-after the coal pillar".When the bump pressure occurs,the fully-mechanized top coal caving face during rock burst accident concentrated in the 50 m range of coal pillar boundary,and the location and times of rock burst accident are related to the length of the coal pillar.With the increase of the striking length of the overlying pillar,the distance between the fully-mechanized caving face and the boundary of the pillar increases when the rock burst accident occurs.At the same time,the probability and failure strength of the rock burst accident in the area near the coal pillar also increase.