隧道揭煤区域预测最小超前距研究及应用

当公路隧道在掘进过程中穿越煤系地层时，将会面临煤与瓦斯突出的风险。确保隧道安全生产，提前准确测定煤层突出参数是关键。隧道在大断面开挖应力扰动情况下，研究分析隧道揭煤区域预测最小超前距、确保隧道安全施工，具有重要的意义。以宝鼎2号隧道工程为例，采用理论分析和数值模拟的方式，对隧道开挖时应力分布规律进行研究分析，得出煤岩应力场分布特征，并推导出宝鼎2号隧道揭煤区域预测最小超前距为14 m。对宝鼎2号隧道ZK15+895 m煤层进行现场预测应用，测得煤层原始应力区瓦斯含量远大于煤层应力扰动区内瓦斯含量，说明在煤层原始应力区内测定的瓦斯参数指标更能真实、准确地反映本煤层突出危险性。

Research and application of minimum advanced distance in tunnel uncovering coal area

When the road tunnel passes through the coal measures strata，it will face the risk of coal and gas outburst.To ensure safe production of tunnel，it is the key to determine the parameters of coal seam ahead of time.In the case of large section excavation stress disturbance，it is of great significance to study and analyze the minimum lead distance of tunnel uncovering the coal area to ensure the safety construction of the tunnel.In this paper，taking Baoding No.2 tunnel as an example，using theoretical analysis and numerical simulation analysis of and research on the distribution of the stress of tunnel excavation，the coal rock stress field distribution characteristics，and deduced the minimum distance for the advanced regional prediction of coal uncovering tunnel 14 m.At the same time，the application of Baoding No.2 tunnel ZK15+895 m coal field prediction，coal seam gas content should be measured the original stress area is far greater than the stress of coal seam gas content in disturbance area，gas parameters in original coal seam stress area was more true and accurate response of the coal seam outburst danger.