Because the upper rocks are influenced after the mining lower coal, they glide along the primary bursting surface, and the upper rock layers can form surface-contact fabric by its shear and bulge function.

• 作者认为，下煤层开采后上覆顶板岩层受到二次扰动，其破坏移动主要是沿原有破裂面滑移，由于剪胀的作用，上覆岩层能够形成面接触的覆岩基本结构特征。