浅埋煤层长壁开采顶板岩层的不稳定性态

针对浅埋煤层顶板关键层破断后的不平衡特性和运动特征，应用初始后屈曲理论和突变理论探讨了顶板结构的不稳定性态，给出了关键层破断后顶板结构回转失稳的必要充分条件，建立了铰接体系在回转状态下的稳定性准则，确定了有无支护时顶板岩层稳定状态下的开采高度.研究发现，顶板破断后岩块的台阶下沉与回转失稳必居其一；回转失稳由两岩块相向旋转形成；岩块在铰接处出现塑性铰只是顶板结构回转失稳的必要条件，顶板结构呈瞬变体系才是体系失稳的充分条件.结果表明，根据浅埋煤层长壁工作面顶板结构的结构特征、岩体材料和上覆厚松散沙层等赋存状况，可进一步确定顶板破断后岩块的运动状态和结构呈瞬变体系时的几何特征；采高是人为控制顶板结构稳定的要素之一，单纯降低采高并不一定安全，控制最大回转角才能保证老顶破断后岩块的稳定性.

Instability behavior for roof strata in shallow seam longwall mining

According to the non-equilibrium characteristics and the motion properties of the broken key stratum in shallow seam long-wall mining,studied the instability behavior of the roof structure by applying the initial post-buckling theory and the catastrophe theory to derive the necessary and sufficient conditions for the rotary instability of rock blocks after main roof breaking,built stability criteria for hinge structure in a state of rotation and determined the mining height with and without the support in a...