浅埋煤层大采高工作面顶板结构分析

Roof structure analysis on large mining height longwall face in shallow coal seam

浅埋煤层大采高工作面应用普遍,其顶板结构理论和支护阻力计算有待深入研究。大采高工作面随着采高增大,顶板冒落带高度增大,部分地质基本顶具有等效直接顶特征。根据等效直接顶垮落充填程度的不同,将等效直接顶分为3种类型,常见的是一般充填型,基本顶将形成高位台阶岩梁结构。在实测和模拟研究的基础上,考虑顶板破断角,建立了浅埋煤层大采高"斜台阶岩梁"结构模型,给出了支架工作阻力的计算公式。最后,实例分析了等效直接顶厚度、基本顶关键块长度、基本顶关键块厚度对支架支护阻力的影响,验证了公式的可靠性。

The face with large mining height is widely used in shallow coal seams, but its roof structure theory and support resistance have not been well studied. With the increase of mining height, the caving roof increases, and part of geological main roof has features of equivalent immediate roof. According to the caving roof filling degree, the equivalent immediate roof is classified to three types. The common type is general filling type where the main roof forms step voussoir beam structure. Based on the field measurement result and simulation test, the ＂oblique step beam＂ structure model is established with the roof breaking angle into consideration, and the proper support resistance calculation formula is put for- ward for faces with large mining height in shallow coal seam. Finally, the effects of equivalent thickness of immediate roof, the main roof key block length and thickness on the support resistance are analyzed in real example, and the support resistance formula has been validated.