浅埋薄基岩高强度开采工作面初次来压基本顶结构稳定性研究

Stability of main roof structure during the first weighting in shallow high-intensity mining face with thin bedrock

为了更合理地进行浅埋采场围岩控制设计,针对工作面出现的顶板沿煤壁大范围切落压架等异常矿压现象,对其发生机理进行了理论分析,得到载荷层厚度、采高、工作面长度的增加导致基本顶破断岩块的高长比增大;由最小势能原理得到了基本顶岩块发生回转失稳的极限位置,由于破断岩块的高长比增加,岩块回转过程中水平挤压力变化曲线斜率减小,而铰接面高度变化曲线斜率增大,铰接结构达到极限平衡位置所需回转的角度增大,导致基本顶结构不容易出现回转失稳,而极易发生滑落失稳。根据浅埋高强度采场顶板结构所特有的失稳形式,提出了确定支架合理工作阻力的动载荷法,并对乌兰木伦井田31402工作面初次来压进行了分析。

For achieving better surrounding rock control in shallow working face, the mechanism of abnormal overlying strata behavior such as large-scale shear-caving along the rib is analyzed in this paper. The scale between the height and the length of key block increases because of the increase of the overburden load, mining height and the length of working face. Limit position of rotary instability is obtained according to the principle of minimum potential energy. The slope of horizontal extrusion pressure curve decreases while the slope of the height of articulated surface increases in the turning process of the key block because of increasing of the scale between the height and the length, and the allowing rotation angle before the hinged structure turning to the limit equilibrium position also increases, which is not likely to cause rotary instability of the hinged structure. However, sliding instability is apt to occur. According to the specific instability form of shallow high-intensity mining face, dynamic method for the determining of the supporting resistance is put forward, then first weighting of 31402 working face in Wulanmulun Mine is analyzed.