硫化氢隧道喷射混凝土腐蚀破坏机理与防治技术研究

Analysis of Corrosion Failure Mechanism and Construction Technology of Shotcrete in Tunnel Hydrogen Sulfide Environment

结合国道569曼德拉至大通公路段内的祁连山2#隧道的施工实践,分析了隧道因硫化氢环境影响造成的初支混凝土强度降低、腐蚀破坏的机理;提出了采用径向锚杆封堵法减少硫化氢与混凝土接触、增强混凝土自身在硫化氢环境中的抗腐能力(如采用气密性混凝土、硫酸盐水泥替代硅酸盐水泥、无碱速凝剂)等防治措施;并通过混凝土外加剂试验、分层喷射厚度试验,发现喷射混凝土中添加粉煤灰相对于矿粉具有更强的抗硫性能,确定了6~7 cm的分层厚度更有利于控制混凝土的掉块回弹现象。相关研究成果可为类似硫化氢环境中喷射混凝土的施工提供有效借鉴。

Combined with the construction practice of Qilianshan 2#tunnel in the section of Mandala to Datong of National Highway 569,the mechanism of the strength reduction and corrosion damage of the primary support concrete caused by the influence of hydrogen sulfide environment is analyzed.The prevention and control measures are proposed,including using radial bolt plugging method to reduce the contact between hydrogen sulfide and concrete,enhancing the corrosion resistance of concrete itself in the hydrogen sulfide environment(such as using air-tight concrete,sulfate cement to replace silicate cement,and alkali-free quick-setting agent).Through the concrete admixture test and the layered shotcrete thickness test,it is found that the fly ash added to shotcrete has stronger sulfur resistance than the mineral powder,and the layered thickness of 6-7 cm is more conducive to controlling the block rebound phenomenon of concrete.The relevant research results can provide effective reference for the construction of shotcrete in the similar hydrogen sulfide environment.