FLAC3D模拟采动岩体渗流规律

为从根本上研究煤层开采工程中因顶板冒落、放顶垮落造成的顶板突水通道的变化规律,首次运用FLAC3D数值软件的应力-渗流耦合系统,结合工程实践,系统分析了采动岩体的渗流矢量、渗流速度、孔隙压力及导水边界线动态发展的普遍规律和分布特征,进行了顶板突水危险区域的识别,得出了一些对防治采场顶板突水有益的结论,可为煤矿顶板突水防治提供理论依据.数值模拟结果表明采动岩体渗流通道的发展明显受煤层开采的影响,且当主关键层破断时,采场最易发生顶板突水事故.在此基础上,将采场的渗流动态变化特征与采动岩体的破断、运动规律结合分析,给出了采场顶板破断及破断岩块再组合压实过程中渗流裂隙的扩展、闭合普遍演化过程.如果水源有限且现有设备能及时排除水患,当煤层采完后,采动岩体能重新压实闭合失去导水性能,地下水位能逐步恢复,即保护第四系及地表水的采煤技术可以实现.同时证明FLAC3D的应力-渗流耦合系统能预测并预算采动岩体裂隙产生、发展、闭合及相关危害性的可靠的数值定量分析软件,可作为一个新方法在顶板突水防治和保水采煤技术中应用.图5,表1,参11.

Numerical Simulation of Seepage Regularities with FLAC3D in the Overlying Strata in Mining Rockmass

To study the change regularities of water inrush channel in the overlying strata induced by the roof breakage and the roof caving, the FLUID-MECHANICAL function of the Fast Lagrange Analysis of Continua in 3 Dimension(FLAC3D)was designed to calculate the cranny expanding and close phases during the roof breakage and recombination. Combined with the practical engineering, the features of dynamic development and distribution of the seepage vector, seepage velocity and its boundary were systematically analyzed. Some reasonable achievements were applied in the prevention and control of water inrush. The result shows that the water inrush channel is influenced obviously by the coal mining phases. The risk of water inrush is highest when the main key strata break. After the coal mined, the overlying strata is reloaded so the cranny is closed until lost its ability of seepage. It is concluded that the underground water level return to normal situation after coal seam is mined, so the coal mining technology with quaternary and surface water conservation is realized. And it proves that the FLAC3D is one of the credible numerical qualitative analysis methods to forecast the cranny's initiation, propagation, close and other hazards (such as the water inrush and the groundwater runoff), which are rationally used to prevent and control of roof water inrush and to conserve water in coal mining. 5figs.,1tab.,11refs.