临空工作面坚硬顶板初次来压的步距端部切断控制法

Step End Cutting Control Method for the Initial Weighting of Hard Roof in Gob Side Working

针对具有坚硬顶板的临空初采工作面,建立了其采空区1边简支、3边固支的力学模型,并据此确定出初次来压步距为63 m。为了避免顶板大面积突然冒落产生的工作面飓风事故,确定采用端部切断坚硬顶板法弱化顶板以降低工作面的初次来压步距。按照顶板切落碎胀后充满采空区并有效支撑上覆岩层的原则,确定坚硬顶板端部切断高度为12 m,此时坚硬顶板已成为悬臂梁;通过建立悬臂梁力学模型确定出此时工作面的初次来压步距为22 m,符合安全生产的要求。现场试验表明,该工作面坚硬顶板端部切断12 m后,初次来压步距减小为16.5 m,消除了顶板大面积突然冒落的安全隐患,保证了工作面的安全回采。

Aiming at the initial mining face with hard roof,the mechanical model of one side simply supported and three sides fixed supported in the goaf is established,and the initial weighting step is determined to be 63 m.In order to avoid the hurricane accident of the working face caused by the sudden collapse of the roof in a large area,it is determined to cut the hard roof at the end to weaken the roof to reduce the initial weighting step of the working face.According to the principle that the roof is full of goaf after cutting and expanding and effectively supports the overlying strata,the cutting height of the hard roof end is determined to be 12 m.At this time,the hard roof has become a cantilever beam.Through the establishment of cantilever beam mechanics model,it is determined that the initial weighting step of the working face is 22 m,which meets the requirements of safe production.The field test shows that after the hard roof end of the working face is cut off by 12 m,the initial weighting step is reduced to 16.5 m,which eliminates the hidden danger of sudden roof caving in a large area and ensures the safe mining of the working face.