矿柱安全留设尺寸的宽度折减法与应用

Width reduction method and its application to determining safety size of pillar

从岩石强度理论出发，提出房柱式开采中矿柱安全留设尺寸的宽度折减法思想，通过不断折减矿柱宽度，研究矿柱由稳定状态向临界失稳状态演化过程，从而得到矿柱的临界宽度，引入矿柱安全系数，获得矿柱安全留设尺寸。采用宽度折减法对磨坊矿3#井房柱法开采矿柱安全留设尺寸进行研究，获得不同矿房跨度下矿柱的安全留设宽度。将宽度折减法得到的安全矿柱宽度与Lunder经验公式比较，研究发现，宽度折减法得到的安全矿柱宽度和Lunder经验公式的计算结果较为吻合且偏安全。结合磨坊矿3#井的开采条件和矿柱宽度折减法分析结果，确定矿房基本参数为：矿房跨度为13 m左右，矿柱宽度为5.0～5.5 m。通过对磨坊矿3#井采空区上覆岩层移动规律的监测，发现岩层相对稳定，地表沉降量控制在120～150 mm之间，用宽度折减法分析得到的矿房基本参数是合理的。

Based on the strength theory of rock, a width reduction method for determining safety size of pillar is proposed in room and pillar mining. Through reducing pillar width gradually, the process of pillars from stable state to limit equilibrium state is studied;and the pillar critical width is obtained. Then the pillar safety width can be determined via introducing the pillar safety factor. By the width reduction method, the pillar safety width of Mofang mine No. 3 is studied to obtain the pillar safety widths in different spans. It is shown that the pillar safety width calculated by width reduction method is in good agreement with that by the Lunder theory through comparison;and the former is safer. According to the mining conditions of Mofang mine No. 3 and the results calculated by width reduction method, the pillar widths are determined to be from 5 m to 5.5 m, responding to the pillar span of 13 m. By monitoring the goafs overlaying strata of Mofang mine No. 3, it is found that the strata movement is relatively stable;the values of ground surface settlement are controlled in the range between 120 mm and 150 mm. To a certain extent, the fundamental parameters of room obtained by width reduction method are reasonable.