西南复杂艰险山区铁路隧道超前地质预报技术

Advanced Geological Forecasting Techniques for Railway Tunnels in the Complex and Treacherous Mountainous Areas of Southwest China

西南复杂艰险山区铁路具有隧线比高、隧道深埋特长、地质条件复杂等特点,工程地质问题突出,隧道施工过程中易发的塌方、突泥涌水、瓦斯爆炸(突出)等危害。为提高隧道超前地质预报的针对性、有效性和系统性,分析总结了各类常规超前地质预报方法的适用条件、优缺点以及应用环境,从而提出不同工况、不同类型的不良地质情况的超前预报方法选择与组合,进而构建不同预报方法选择与组合和“四结合”的综合超前地质预报模式。实践表明:(1)各种超前地质预报方法有其方法特点和一定的适用范围;(2)西南山区工程地质问题复杂,应根据隧道施工环境及主要的不良地质特征,充分发挥各方法优势并采用合理的方法组合,开展综合预报;(3)铁路隧道综合超前地质预报应采用勘察资料与洞内预报相结合、地质与物探相结合、长距离预报与中短距离预报相结合、不同物探方法相互结合的“四结合”模式;(4)构建的超前地质预报方法选择及组合和“四结合”模式可提高不良地质探测的针对性、有效性和系统性,有利于工程地质问题的解决,达到预报成果有效指导施工、降低施工风险的目的。

The railways in the complex and treacherous mountainous areas of Southwest China are characterized by high percentage of tunnels,deep and long tunnels,and complex geological conditions,which highlight prominent en⁃gineering geological issues and hazards like collapses,mud outbursts,and gas explosions(outbursts)during tunnel construction.To enhance the specificity,effectiveness,and systemic of advanced geological forecasting for tunnel construction,this paper analyzes and summarizes the applicable conditions,advantages and disadvantages,and the application environments of various conventional advanced geological forecasting methods.It proposes the selection and combination of forecasting methods for different working conditions and types of adverse geological situations,thereby establishing a comprehensive advanced geological forecasting model integrating different methodological se⁃lections and combinations with a"Four-combination"approach.Practice has shown that:(1)each advanced geologi⁃cal forecasting method has unique characteristics and a certain application scope;(2)due to the complex engineering geological issues in the Southwest mountainous areas,it is crucial to fully utilize the advantages of each method and adopt a reasonable combination for comprehensive forecasting based on the tunnel construction environment and pri⁃mary adverse geological features;(3)comprehensive advanced geological forecasting for railway tunnels should adopt a"Four-combination"model,integrating survey data with in-tunnel forecasting,geological and geophysical meth⁃ods,long-distance forecasting with medium and short-distance forecasting,and the integration of different geophysi⁃cal methods;(4)the established method selection and combination for advanced geological forecasting and the"Four-combination"model can enhance the specificity,effectiveness,and systemic of detecting adverse geological conditions,with facilitating the resolution of engineering geological issues,effectively guiding construction,and re⁃ducing construction risks.