渭北矿区厚黄土层采动变形数值模拟研究

Mining deformation numerical simulation of thick loess layer in Weibei mining area

渭北矿区黄土层覆盖厚度占开采深度的30%～70%,采煤沉陷规律具有特殊性。以渭北矿区大佛寺煤矿首采工作面开采为实例,利用FLAC软件分析了基岩开采沉陷引起的黄土层附加应力与变形的基本特征。数值模拟表明,采动黄土层中的附加竖向应力随着深度增加而增大,在地表附近水平向附加应力相对增量远大于竖直方向,地表变形由水平向附加应力所主导,在采空区上方产生体积压缩,在煤柱上方产生体积膨胀,地表土体单元的体积变形与水平变形及竖向变形具有相同的分布特征。本文揭示了采动黄土层变形的特殊机理,为建立厚黄土层矿区开采沉陷变形预计模型奠定了基础。

The thickness of loess layer in Weibei mining area accounts for 30%～70% of mining depth and the rules of mining subsidence has particularity.Taking the first coal mining face of Big Temple Mine in Weibei mining area for example,the basic characteristics of additional stress and deformation which caused by bedrock subsidence is analyzed by using FLAC software.The numerical simulation indicates that additional stress of loess layer in vertical direction will increase with the increase of mining depth and the relative increment of additional stress in horizontal direction is much larger than that of in vertical direction near ground surface.Surface deformation is led by additional stress in horizontal direction.Volume compression will occurs upon the mined out area and volume expansion will occurs upon coal pillars.The volume deformation of soil mass and horizontal deformation has the same distribution characteristics.Meanwhile,the volume deformation of soil mass and vertical deformation has the same distribution characteristics.The special mechanisms of loess layer deformation will be revealed and the foundation of subsidence prediction model in thick loess layer mining area will be established.