川西高原某隧道幔源气逸出机理及防控研究

Research on the Mechanism of Mantle-derived Gas Emission and Prevention&Control Measures in a Tunnel in the Western Sichuan Plateau

川西高原地区特殊的构造和岩性为幔源气提供了赋存环境。本文针对幔源气成因、出气段落超前地质预报探测原则、检测与监测进行了阐述,总结了幔源气出气段工作思路:(1)辨识幔源气类型及其不同浓度下的危害;(2)树立“物钻结合,长短结合”的超前地质预报理念;(3)加强气体的检测与监测,加强幔源气的通风管理。通过以上探测及防控手段,实现了对岩浆岩幔源气的可防可治,保证了施工安全。研究成果可为类似地质背景环境的隧道施工提供针对性探测及防控思路。

The distinctive structure and lithology of the western Sichuan Plateau offer an occurrence environment for mantlederived gas.This paper delves into the origin of mantle-derived gas,the advanced geological prediction principles for gas emission sections,as well as detection and monitoring methods.The working strategies for gas emission sections are summarized as follows:(1)Identifying the type of mantle-derived gas and assess its hazards under varying concentrations.(2)Combining geological surveys with drilling and long-range with short-range prediction.(3)Enhancing gas detection and monitoring,as well as ventilation management for the emission of mantle-derived gas.These detection and prevention measures enable the prevention,control and mitigation of magma-derived mantle gas,thereby ensuring construction safety.The research findings can offer targeted detection and prevention strategies for tunnel construction in similar geological settings.