沿充填体掘巷“二次掘采”全过程底板稳定性研究

Study on the Floor Stability in the Whole Process of Twice Excavation and Mining Along the Backfill

首先对沿空留巷、沿空掘巷的研究进展进行了简要梳理。在此基础上引出了一种新型无煤柱开采技术——巷内预充填无煤柱掘巷(沿充填体掘巷),阐述了其“三阶段”顶板应力分布规律,并运用数值模拟对沿充填体掘巷在“二次掘采”全过程底板的稳定性进行分析。结果表明:在“二次掘采”整个过程中充填体始终处于高应力状态,巷道围岩经历了反复加卸载,充填体与煤帮的支承压力峰值呈交替出现。在本工作面回采阶段,充填体帮和煤帮处应力峰值均达到掘采全过程中的最大值,分别为24.2 MPa、27.2 MPa,且在距超前工作面5 m处底鼓量达到最大,为321.8 mm。

Firstly,the research progress of gob-side entry retaining and gob-side entry driving were briefly summarized.On this basis,a new type of mining technology without coal pillar was introduced,that is,pre-filling in the roadway without coal pillar(Roadway driving along the backfill),and the roof stress distribution law of“three stages”was expounded.The floor stability in the whole process of twice excavation and mining was analyzed by numerical simulation.The results show that the backfill always maintains a high stress state in the whole process of twice excavation and mining,the rock mass around the roadway has undergone repeated loading and unloading,and the peak abutment pressure of backfill and solid coal wall appears alternately.At the mining stage of this working face,the peak values at the backfill wall and solid coal wall both reach the maximum,which are 24.2 MPa and 27.2 MPa respectively,and the floor heave reaches the maximum value of 321.8 mm at 5 m away from the working face.