Analysis of Mechanical Characteristics and Instability Law of Inverse Fault under the Influence of Mining

• Main Authors: Yuanhui Li, Rui Zhou
• Format: Article
• Language: English
• Published: Universidad Nacional de Colombia 2018-04-01
• Series: Earth Sciences Research Journal
• Subjects: Reverse fault; Normal stress; Shear stress; Fault instability; Rock burst
• Online Access: https://revistas.unal.edu.co/index.php/esrj/article/view/72249
• ISSN: 1794-6190; 2339-3459

In order to explore the mechanical characteristics and stability of the reverse fault under the influence of mining, an inverse mechanics model has been built under work face mining conditions, according to the law of working surface pressure distribution. As a result, a theoretical calculation equation of the normal and shear stresses in the fault zone have been deduced to obtain the stress variation rule between the working surface and the fault layer, under distance conditions of 10, 30, 50, and 70m. With distance conditions of 10 and 30m, the working surface mining stress had an obvious effect on the reverse fault, resulting in a changing trend of firstly increasing, then decreasing, and increasing again in the normal and shear stresses of the fault zone as a whole. With distance conditions of 50 and 70m, the working face mining stress had little effect on the reverse fault; furthermore, the normal and shear stresses exhibited a changing trend of gradually increasing. At a later stage, a simulation of the above distance plans was conducted using the FLAC3D numerical simulation software. The results demonstrated that the influence range of the mining stress on the working face under the spacing distances of 10 and 30m included the fault zone, while under the distance conditions of 50 and 70m, the fault zone was excluded. On this basis, the fault zone stability was analysed under four types of spacing conditions by means of the Mohr Coulomb theory rule and fault activation determination. It is concluded that the fault zone stability was high, with increasing distances between the working face and fault zone. The least sufficient stability was located near the working face, where the fault zone stability was so poor that it is likely to result in impact fracture.