隧道围岩构造软岩大变形发生机理及分级方法

通过系统分析国内外隧道围岩大变形案例,发现应力场、地质构造、地层岩性等因素是驱动隧道围岩大变形孕育发生的根本条件,并严格受构造控制,进而提出构造软岩大变形的基本概念;根据大变形的构造控制理念与发生机理,对隧道构造软岩大变形分类进行了重新界定(断层型、碎裂型和小夹角型).以岩石强度应力比为基础,突出构造运动影响,量化考虑...

Mechanism and Classification of Tectonic-induced Large Deformation of Soft Rock Tunnels

Based on the analysis of large deformation cases of tunnel surrounding rock both at home and abroad, the present study found that the factors such as in-situ stress, geological structure and formation lithology are the basic conditions for the occurrence of large deformation of tunnel surrounding rock. Then, a concept of tectonic-induced large deformation of soft rock was proposed. According to the concept and mechanism of tectonic-controlled large deformation of tunnel surrounding rock mass, the classification of large deformation of soft rock in tunnel was redefined (fault type, fragmentation type and small angle type). Based on the ratio of rock strength and in situ stress, emphasizing the influence of structural movement, and considering five factors including stratum age, occurrence of dominant structural plane, rock strength, rock strata thickness and rock mass integrity, a new grading method for large deformation of tunnel surrounding rock in different geological exploration stages was proposed. The new grading method for tectonic-induced large deformation of tunnel surrounding rock mass proposed in this paper was systematically verified by employing 18 large deformation cases of Yakou tunnel, Yanbian tunnel, Xinlin tunnel and so on. Results demonstrated that the grading method proposed in the present study is reliable. The research results are of great importance for the understanding of the large deformation mechanism as well as the identification and control of large deformation disasters of tunnel surrounding rock mass.