急倾斜中厚煤层双斜开采顶板垮落堆积与应力演化特征

Roof collapse accumulation and mining stress evolution characteristics of double inclined mining in steeply inclined medium-thick coal seam

  • 摘要: 摘要:60°以上急倾斜中厚煤层长壁综合机械化开采方法亟待突破,以四川绿水洞煤矿3212工作面为工程背景,基于系统研究和现场实践,在俯伪斜开采的基础上提出双斜开采的采煤方法,明确双斜开采的优点、工程难点和致灾隐患,并采用物理相似模拟、数值模拟等方法,分析双斜开采基本顶破断矸石充填滑移堆积规律,以及顶板应力演化过程。结果表明:双斜开采工作面布置需要与矿井开采设计相协调,工作面两巷维护难度大,其中回风巷侧受采动应力影响大,而运输巷与工作面支架的协调配合难度大;双斜开采由于其异形采空区顶板结构,垮落步距更大,其矸石垮落堆积呈倒三角形态并且存在周期性滑移特征,并且由于大块矸石堆积造成的工作面上部和中部来压的非均匀来压现象;双斜开采原岩应力随工作面的推进逐渐增大,工作面倾斜上、中、下三部分来压强度不同,一般倾斜中上部来压大于下部,但倾斜下部支承压力应力集中系数大于工作面中上部,双斜开采顶板应力演化特征受工作面形状和推进距离的影响,并由于巷道调斜角作用,应力释放范围呈现由倾斜上部至下部逐渐变小的非对称特征。

     

    Abstract: Abstract :Longwall comprehensive mechanized mining method for steeply inclined medium-thick coal seams above 60 ° urgently needs to be broken through. Taking the 3212 working face of Sichuan Lvshuidong Coal Mine as the engineering background, based on systematic research and field practice, the mining method of double-inclined mining is proposed on the basis of dip-pseudo-inclined mining. The advantages, engineering difficulties and hidden dangers of double-inclined mining are clarified. Physical similarity simulation and numerical simulation are used to analyze the filling and sliding accumulation law of broken gangue in the basic roof of double-inclined mining and the evolution process of roof stress. The results show that the layout of the double inclined mining face needs to be coordinated with the mining design of the mine, and the maintenance of the two lanes of the working face is difficult. Among them, the side of the return air lane is greatly affected by the mining stress, and the coordination between the transport lane and the working face support is difficult ; due to its special-shaped goaf roof structure, the double-inclined mining has a larger caving step, and its gangue caving accumulation is inverted triangle and has periodic sliding characteristics, and the non-uniform weighting phenomenon of the upper and middle parts of the working face caused by the accumulation of large gangue. The stress of the original rock in the double in-clined mining increases gradually with the advance of the working face, and the pressure intensity of the upper, middle and lower parts of the working face is different. Generally, the pressure in the upper part of the inclined middle is greater than that in the lower part, but the stress concentration coefficient of the sup-porting pressure in the lower part of the inclined is greater than that in the upper part of the working face. The stress evolution characteristics of the roof in the double inclined mining are affected by the shape of the working face and the advancing distance, and the stress release range is gradually reduced from the upper part of the inclined to the lower part due to the effect of the inclined angle of the roadway.

     

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