高瓦斯隧道新型喷射混凝土配制及气密性

为研究适用于高瓦斯隧道的新型喷射混凝土的材料性能及气密性影响因素，以桐梓隧道为工程依托，通过配合比试验、气密性测试和现场试喷确定了满足强度、和易性及气密性要求且施工性能好的新型喷射混凝土，运用气压差值法和压汞法分析了气压和孔隙结构对新型喷射混凝土气密性的影响，给出了适用于新型喷射混凝土气密性测试的最佳测试压力及其透气系数。结果表明：新型喷射混凝土配合设计为：水灰比0.38，水泥：粉煤灰：玄武岩纤维=360: 90: 1.5（kg/m3）；与孔隙率相比，最可几孔径的拟合相关系数更高，能更好的反映其与混凝土透气系数的关系。

Preparation and Air Tightness of New Type Shotcrete for High Gas Tunnel

In order to research the material properties and air tightness influencing factors of new shotcrete suitable for high gas tunnels, Tongzi Tunnel is taken as the project support, and through mix ratio test, air tightness test and on-site trial spraying, a new shotcrete with good construction performance and meeting the strength, workability and air tightness requirements is determined. The influence of air pressure and pore structure on the air tightness of new shotcrete is analyzed by using air pressure difference method and mercury intrusion method, and the optimum test pressure and air permeability coefficient for the air tightness test of new shotcrete are given. The results show that the mix design of new shotcrete is: water cement ratio 0.38, cement: fly ash: basalt fiber=360: 90: 1.5 (kg/m3); compared with porosity, the fitting correlation coefficient of the most probable pore size is higher, which can better reflect the relationship between it and the permeability of concrete.