近距离下穿既有隧道的矿山法隧道支护方案选择

随着城市基础设施建设的不断推进，地下隧道建设已经成为重要的组成部分。然而，在地质条件复杂、既有隧道密集的城市环境下，隧道建设往往会遇到各种挑战，尤其是采用矿山法近距离下穿既有隧道更为困难。在这种建设中，设计技术方案、支护措施、施工方案等方面都需要考虑到。以贵阳某在建项目为例，从设计技术方案和施工要求入手，结合有限元分析和现场监测数据，探讨如何在泥岩地层条件下安全施工近距离下穿既有小净距隧道的问题，旨在为同类型工程提供参考和指导。

Selection of Mining Method Tunnel Supporting Schemes for Undercrossing Existing Tunnels at Close Range

With the continuous advance in the construction of urban infrastructure, the construction of underground tunnel has become an important part. However, in cities with the complex geological conditions and dense existing tunnels, the tunnel construction often faces various challenges, especially it is more difficult to undercross the existing tunnels in the close range by the mining method. In this construction, the design technological scheme, supporting measures and construction scheme are required to consider. Taking a project under construction in Guiyang as an example, starting from the design technical scheme and construction requirements, combined with the finite element analysis and the on-site monitoring data, the problem how to achieve the safe construction in close range to undercrosss the existing small-distance tunnel under the mudstone formation condition is discussed. The aim is to provide the reference and guidance for similar projects.