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根据工程地质资料分析,岩爆是秦岭公路隧道2号通风竖井施工过程中的主要难题。岩爆机制是指岩爆发生的物理过程,与岩石的颗粒大小、颗粒胶结和粒间孔隙等结构特征密切相关。根据颗粒流基本理论和竖井混合片麻岩的基本力学特性,进行混合片麻岩细观颗粒参数标定研究。颗粒大小不是一个自由参数,通过颗粒流模拟的相似比分析,采用强度折减方法进行竖井岩爆机制的颗粒流模拟。研究表明,岩爆孕育的细观机制为平行于开挖面的微裂纹萌生—微裂纹扩展、聚合—宏观裂纹的形成,为压致张剪断裂破坏,主要是由张拉裂纹扩展、聚合引起的,是一个渐近破坏过程。研究成果为竖井岩爆稳定性分析提供初步依据。
According to the analysis of engineering geological data, rock burst is the main problem in the construction of ventilation shafts on No. 2 Qinling Highway Tunnel. Rockburst mechanism refers to the physical process of rockburst and is closely related to the structural features of rock particle size, particle cement and intergranular porosity. According to the basic theory of particle flow and the basic mechanics characteristics of shaft mixed gneiss, the study on the parameter calibration of mesoporous mixed gneiss was carried out. The particle size is not a free parameter. Through the similarity analysis of particle flow simulation, the particle flow simulation of shaft rock burst mechanism is carried out by strength reduction method. The results show that the meso-mechanism of rock burst is the micro-crack initiation, micro-crack growth and polymerization-macro-crack formation parallel to the excavation face. It is the fracture caused by compressive tension and shear failure, which is mainly caused by the expansion of the tensile crack and the polymerization It is an asymptotic destruction process. The research results provide a preliminary basis for rockburst stability analysis.