综采薄煤层采动底板变形破坏规律实测分析

Measurement of Mining-Induced Floor Failure Regularity for Thin Coal Seams Using Fully Mechanized Coal Caving

为了研究兖州煤田综采薄煤层底板采动变形破坏规律,应用现场应变实测系统在兖矿集团杨村煤矿4602综采工作面进行了现场实测,得到了底板2个监测钻孔8个应变传感器探头的的应变增量随工作面推进的变化曲线,通过2个监测钻孔监测数据的综合比较,确定底板破坏深度介于8.4～10.1m之间;结合现场底板变形实测,分析了煤壁前方超前支承压力影响的范围与底板深度的关系并给出了定量表达式;应变增量曲线反映出的周期来压步距为8.9m,这与工作面矿压监测数据反映的周期来压步距基本一致.在此基础上,结合课题组在兖州矿区底板破坏深度实测的已有数据,提出了适合兖州地区的底板破坏深度的经验公式,为兖州煤田下组煤开采结合其他突水影响因素确定安全可采分区提供了可靠依据.目前,位于可采区内的杨村井田2个工作面的安全回采已经证实了预测的准确性.这一问题的研究对鲁西南下组煤煤炭资源的安全开采具有重要的理论与现实意义.

In order to research the mining-induced floor deformation and failure of thin coal seams using fully mechanized caving method,we performed the in-situ test by strain testing system in No.4602 fully mechanized coal face of Yangcun coal mine,Yanzhou coal mining company and get the variation curve of strain increment of eight strain transducers in two monitoring borehole.Through the comprehensive comparison of monitoring data,we determined that the failure depth of the floor is in a range of 8.4~10.1 m.Taking the in-situ strain test as example,we discussed the relationship between the fore abutment pressure influence range and the depth of floor and gave out the quantitative expressions.The strain increment curve reflects that the pace of periodic breakage is 8.9 m,much similar to monitoring results of ground pressure.Based on this,empirical formula of failure depth of floor applicable in Yanzhou area is put forward based on the existing measured data.This formula,in combination with other factors,is used to determine the safe area for mining the lower coal seam with a certain risk of water inrush.Up to now,the result is verified to be reliable by the successful mining of the two coal faces in the safe area.So the research of this problem has a profound significance in both the theory and the reality for successful mining of the lower coal in southwest Shandong.