中文摘要：

大倾角煤层群长壁采场所形成的顶板结构较单一大倾角煤层更为复杂,采用理论分析和相似材料模拟实验研究手段,揭示了该类煤层顶板结构形成及演化特征.研究表明,大倾角煤层群下层煤采场顶板易形成非对称低位梯阶关键层,一般为二级梯阶,且层位低、厚度小、稳定性差,该结构的周期性失稳直接影响到下层煤采场覆岩、区段煤柱及支护系统的稳定性.低位梯阶关键层受覆岩及上方采空区矸石的法向与切向力作用,易发生拉、剪或复合型失稳,其破坏后可形成倾向堆砌型倾斜砌体结构.低位梯阶关键层破坏易引发层上方区段煤柱压剪失稳,并导致上方梯阶结构群发生大范围破坏.

英文摘要：

The overburden structure in steeply dipping seam group mining area is more complex than sin- gle steeply dipping seam mining, especially in the lower seam mining area, which is analyzed by using theoretic analysis and experimental research, and the result indicate that the asymmetry key lower ladder strata is formed in the mining area of lower seam, which has the characteristic of two steps, lower layer, thickness and instability, and also, the periodic failure of the key lower ladder strata is very important to the stability control of the overlying, section pillar and supporting system. Furthermore, when normal and tangential direction stress ,which is formed at the overlying and failure roof, affect on lower ladder strata structure, tension, shear and composite failure occurred, and incline masonry structure formed in the fail- ure key lower ladder strata, which also induce shear failure of section pillar in the lower Seam, and then large scale overlying strata movement occurs.