浅埋煤层长壁开采顶板岩层灾害控制研究

根据浅埋煤层顶板岩层的赋存特点和长壁开采时基岩老顶的断裂下沉特征，应用初始后屈曲理论和突变理论探讨了初次来压期间基岩老顶的灾害机制和灾害控制，补充了基岩老顶破断后控制岩块滑落失稳的充分条件和岩块触矸前后台阶下沉的判据，确定了台阶下沉量，给出了控制台阶下沉和维持顶板稳定的支护力计算公式，并以神东矿区大柳塔1203工作面为例给出了工程实例。研究发现，顶板破断后岩块处于不平衡状态，台阶下沉的机制是结构的滑落失稳；岩块触矸前后的台阶下沉分别与断裂下沉和开采高度之间存在着确定的关系；顶板强烈来压主要是由结构滑落失稳造成的，控制台阶下沉的实质是控制岩块沿煤壁的滑落失稳。研究结果表明，综合应用初始后屈曲理论和突变理论，可根据顶板结构的赋存状况和结构特征，确定基岩老顶触矸前是否会出现全厚度切落；根据工作面的开采高度和采空区有效充填厚度等，可确定基岩老顶触矸后岩块的运动形式；根据顶板的破断步距、断裂下沉量和岩块摩擦因数等，可确定岩块触矸前后控制台阶下沉的支护力

Study of controlling catastrophe for roof strata in shallow seam longwall mining

In accordance with the occurrence behavior of roof strata and the breaking convergence characteristics of main roof in shallow seam longwall mining, this paper studied the catastrophe mechanism and the catastrophe control of main roof during the first weighting by using the initial post-buckling theory and the catastrophe theory, added the sufficient conditions of instability due to sliding for controlling rock blocks after the main roof breaking, perfected the criteria of step convergence of rock blocks for contacting and not contacting with the waste rock from fallen roof, determined the step convergence values, derived the formulae of support force for controlling the step convergence and ensuring the roof stability, and presented an application with the example of Daliuta 1203 face. It is pointed that the rock blocks are in a state of non-equilibrium after main roof breaking, the mechanism of the step convergence is instability due to sliding of structure; the step convergences before and after contacting with the waste rock from fallen roof have some determinate relations with the breaking convergence and the mining height respectively; the intense roof weighting is mainly caused by key roof block sliding; and controlling step convergence is essentially controlling sliding for rock blocks. The results also indicate that the synthetical application of initial post-buckling theory and catastrophe theory can determinate whether step convergence will take place before contacting with the waste rock from fallen roof in accordance with the occurrence state and structure characteristics of roof rock layer, can determinate the motion form after contacting with the waste rock from fallen roof according to mining height of working face and effective filled thickness, and can determinate the support force for controlling step convergences before and after contacting with the waste rock from fallen roof in accordance with the breaking span, the breaking convergence value and the friction coefficient.