大采高工作面沿空留巷底鼓控制技术研究及应用

Research and Application of Floor Heave Control Technology for Gobside Entry Retaining in Large Mining Height Face

为解决端氏煤矿沿空留巷底鼓大变形问题,对巷道底鼓机理进行了分析,提出并应用切顶卸压和顶底板双梁联合支护技术来控制底鼓。切顶减小了采空区上方顶板往实体煤帮传递的应力,使留巷巷道处于卸压区,弱化了实体煤帮的应力集中程度,进而控制实体煤帮和底板的变形。通过采用“单体+π型梁+工字钢梁”一体化顶底板双梁联合支护技术,避免了单体钻入底煤导致支护失效现象,实现了顶板压力的有利转换,通过顶板压力有效控制底鼓。监测结果表明,切顶卸压使超前底鼓量平均降低25.6%;在切顶条件下,使用底梁较未使用底梁留巷底鼓量降低51.7%。切顶卸压及顶底板双梁联合支护技术能有效控制底鼓,解决端氏煤矿沿空留巷底鼓大变形问题,为类似条件下的沿空留巷底鼓控制提供借鉴。

In order to solve the problem of large deformation of floor heave in gob-side entry retaining in Duanshi coal mine,the floor heave mechanismis analyzed,and the roof cutting pressure relief and roof and floor double beam combined support technology is proposed and applied to control the floor heave.Roof cutting reduces the pressure transmitted from the roof above the goaf to the solid coal side,makes the retaining roadway in the pressure relief zone,weakens the stress concentration degree of the solid coal side,and then controls the deformation of the solid coal side and the floor.The"single pillar+π-type beam+I-beam"is adopted to form the joint support mode of roof and floor double beams,which avoids the support failure caused by single pillar drilling into the bottom coal,and realizes the favorable conversion of the roof pressure,and effectively controls the floor drum through the roof pressure.The monitoring results show that the floor heave before the working face after cutting the top can be reduced by 25.6%on average.Under the condition of cutting the roof,the floor heave of entry retaining with floor beam is 51.7%lower than that without floor beams.Roof cutting,pressure relief and roof and floor double beam combined support technology can effectively control floor heave,solve the problem of large deformation of floor heave along goaf retaining roadway in Duanshi coal mine,and provide reference for floor heave control of gob-side entry retaining under similar conditions.