综放工作面多放煤口协同放煤方法

针对当前综放工作面存在顶煤采出率低、混矸率高、放煤效率低等问题,提出综放工作面多放煤口协同放煤方法。根据给出的综放工作面多放煤口协同放煤方法的定义,以理论分析和数值模拟为手段,研究了多放煤口放煤条件下,起始放煤、中间放煤和末端放煤3个阶段的放煤方法和煤岩分界面特征,提出"多放煤口同时开启逆次关闭"的起始放煤方法。根据放煤口放煤的影响范围,以及顶煤冒落过程中的速度方程和顶煤颗粒移动方程,建立了多放煤口起始放煤方式的算法模型,理论上推导出起始放煤过程中放煤间隔时间差的计算方法,为起始放煤方法的应用提供了方法。通过分析综放工作面的特点,得出综放工作面顶板稳定性、瓦斯浓度、后部刮板输送机运输能力、粉尘浓度、工作面采放协调等是影响和限制放煤口数量的主要因素。以同忻煤矿8202综放工作面煤层条件为例,建立沿工作面方向的数值模拟模型,模拟并对比不同的单放煤口放煤方式和不同放煤口数量的多放煤口放煤的放煤规律、顶煤采出率和放煤效率,得出在多放煤口放煤条件下,放煤过程中的煤岩分界面相对平滑,顶煤采出率随同时打开的放煤口数量增加而增大。多放煤口放煤效率是单放煤口放煤效率的4～8倍,多放煤口放煤的顶煤采出率比单放煤口高5%左右。

Method of synergetic multi-windows caving in longwall top coal caving working face

In terms of the problems of low top coal recovery rate,high gangue mixing rate and low top coal caving efficiency in longwall top coal caving working face,the method of synergetic multi-windows caving was put forward in this paper. Based on the definition of synergetic multi-windows caving method,by means of theoretical analysis and numerical simulation,the top coal caving method and the characteristics of coal rock mass interface at three stages top coalcaving including initial stage top coal caving,intermediate stage top coal caving and end stage top coal caving were studied under the conditions of synergetic multi-windows top coal caving. The initial stage top coal caving method of “open window at the same time and close window in reverse” was proposed. According to the influence range of coal caving at the coal caving point,the velocity and movement equation of top coal particle during the caving process of topcoal,an algorithm model for the initial stage top coal caving method was established,and the calculation method of the time intervals among caving windows in the initial stage caving process was deduced theoretically,which provides a method for the application of the initial stage top coal caving method. By analyzing the characteristics of fully mechanized caving face,it was concluded that roof stability,gas concentration,the transport capacity of rear scraper conveyor,dust concentration and coordination of mining and caving in longwall top coal caving working face are the main factors affecting and limiting the number of caving windows which are opened at the same time with synergetic multi-windows caving method. Taking the coal seam conditions of the 8202 longwall top coal caving working face in Tongxin Coal Mine as an example,a numerical simulation model along the advance direction of the working face was set up tosimulate and compare the top coal caving laws,top coal recovery rate and the top coal caving efficiency of the different top coal caving methods. It was concluded that under the condition of multi-windows top coal caving method,the coalgangue interface is relatively smooth in the process of top coal caving,and the top coal recovery rate increases with the increase of the number of caving windows at the same time,and the efficiency of the multi-windows top coal cavingmethod is 4-8 times as much as the single-window,and the top coal recovery rate of the multi-windows caving method is 5% higher than that of the single-window.