Dynamic Failure Model of Thin Coal and Rock Mass under Uniform Impact Load

Abstract

During the excavation of deep coal and rock mass, the radial stress of the free face changes from three-dimensional compression state to two-dimensional stress, bearing the combined action of dynamic disturbance and static load at the same time. With that, many mines suffer from dynamic disasters, such as coal and gas outburst, rock burst and rock caving during deep mining excavation, which is often accompanied by plate crack, spalling and other disasters, seriously affecting the stability of stope and roadway. Taking thin rectangular coal and rock mass as the research object, the dual equation of the free vibration was derived and the exact solution model of the free vibration was established with the use of Hamilton dual system. Based on the action characteristics of the uniform impact load, the effective mode of the forced vibration was obtained by using the Duhamel integral principle and the orthogonality of the mode function. Based on the third strength theory and the numerical simulation results, the dynamic damage process and development trend of coal and rock mass were analyzed under uniform impact load. It was concluded that the starting position of dynamic damage can be judged by the first order main mode, and the development direction and trend of the damage can be judged by the fifth and sixth order main modes. It was concluded that the vibration mode functions of coal and rock mass with four side fixed

Stress wave propagation and incompatible deformation mechanisms in rock discontinuity interfaces in deep‐buried tunnels

“…The dynamic load response of a rock mass is the synthesis result of the rock response to various weak structural planes and fault zones. The overall dynamic performance is mainly determined by large-scale weak structural planes (Gong et al, 2021;Li et al, 2017Li et al, , 2020Moon et al, 2001;Peng & Zhu, 2012). The vibrational characteristics of rock masses can be also the result of the superposition of forced vibrations caused by excited seismic waves and free vibrations (Kekeç et al, 2015;Li et al, 2018).…”

The Dynamic Response and Failure Model of Thin Plate Rock Mass under Impact Load

“…In the whole dynamic process of mining, and during the beginning, formation, development, and termination of coal and rock dynamic disaster, rock mass will bear the dynamic disturbance from mine earthquake, such as blasting, roof and floor breaking, and rock instability. At present, the mechanical characteristics of rock mass are mainly studied under static load, while the research studies on dynamic mechanical response characteristics are only in the stage of experimental exploration, and the mechanisms of dynamic damage, failure, and disaster-causing are still unclear [35][36][37][38][39][40], because the vibration of rock mass under external force has a significant impact on its mechanical properties [35,37,41].…”