为了使综放工作面遇小煤矿采空区不搬家倒面,提高煤炭采出率,对工作面前方小煤矿采空区实施有限充填加固,使综放工作面能直接回采通过该采空区,为此,提出了人工顶板承载关键层理论,并设计计算出其厚度不小于5 m;试验选用了抗压强度为5.59～7.43 MPa发泡水泥和抗压强度1.93～3.95 MPa的瑞米充填材料作为人工顶板材料,其力学性能可满足要求;采用分层注浆充填方法,使充填材料与实体煤得以充分胶结,形成整体。试验结果表明:采用该技术,回采工作面用25 d复采完126 m长的小煤矿采空区,多采出煤炭近100万t,成功地实现了工作面在厚煤层小煤矿采空区直接推过的安全高效复采。

In order not to have a mining face removing when a fully mechanized top coal caving mining face met a goaf of a former small mine and to improve the C oal mining recovery rate, a limited backfill reinforcement would be conducted in the goaf of the former small mine which was in the front of the coal mining face and thus the fully mechanized top coal caving mining face could be directly passed through the goaf.Therefore a key loading layer theory of an artificial roof was proposed and th e thickness over 5 m of the key layer was designed and calculated. Foaming cements with a compressive strength of 5.597 .43 MPa and a Ruimi backfill material with a C ompressive strength of 1.933 .95 MPa were tested and selected for the artificial roof material.The mechanics performances of the materials could meet the requirement s.A slicing grouting backfill method was applied and thus the backfill materials and solid coal could be fully bound to be integrated.The test results showed that with the backfill technology, within 25 days, the coal mining face had completed the 126 m mining in the goaf of the former small mine and about 1 million t coal was recovered.T he coal mining face successully realized the safety high efficient secondary mining directly passing through the goaf of the former small mine.