地面充填钻孔钻进过程应力-位移演化规律数值模拟研究

Numerical simulation study on stress-displacement evolutionlaw during ground filling drilling process

为掌握地面充填钻孔钻探施工过程中孔壁围岩应力-位移分布及演化规律,探索地面钻孔发生变形破坏的力学机制,从而为钻孔结构设计提供理论支撑,以典型矿井地面充填钻孔施工为研究对象,运用FLAC3D对钻孔钻进过程进行了数值模拟,着重分析了钻进至50、250、500m时钻孔围岩的应力-位移演化规律。研究结果表明:钻孔孔身围岩应力-位移分布是造成其变形破坏的直接诱因,垂直应力、水平应力随着钻孔深度增加呈线性增长;最大垂直位移位于钻孔顶部,钻进到一定深度后增长趋势明显减缓,呈非线性递增趋势,垂直位移的不同步将造成钻孔产生离层;水平位移随钻孔深度整体呈线性增长,峰值位于钻孔底部围岩,水平位移是孔身产生剪错、缩颈变形破坏的直接诱因。研究成果可为类似地面充填、注浆和瓦斯抽放钻孔结构设计优化及施工提供理论指导。

In order to obtain the stress-displacement distribution and evolution law of surrounding rock during ground filling drilling process,explore the mechanical mechanism of deformation and failure in ground drilling,and provide theoretical support for drilling structure design.Taking the construction of typical mine ground filling boreholes as the research object,numerical simulation of the drilling process was carried out using FLAC3D,with a focus on analyzing the stress displacement evolution.law of the surrounding rock of the borehole when drilling to 50 m,250 m,and 500 m.The research results indicate that the stress-displacement distribution of the borehole surrounding rock is the direct cause of its deformation and failure.The vertical stress and horizontal stress increase linearly with the increase of drilling depth.The maximum vertical displacement is located at the top of the borehole,and the growth trend slows down significantly after drilling to a certain depth,showing a non-linear increasing trend.The asynchronous vertical displacement will cause the borehole to produce delamina tion.The horizontal displacement increases linearly with the depth of the borehole,with its peak loca-ted in the surrounding rock at the bottom of the borehole.Horizontal displacement is the direct cause of shear failure and necking in drilling.The research results can provide theoretical guidance for the design optimization and construction of ground filling,grouting,and gas drilling.