Analysis of influencing factors of rockburst surrounding rock failure under dynamic and static loads

Abstract

Rockburst is a serious hazard in tunnel engineering. The key to preventing and controlling rockburst is to clarify the main factors affecting its occurrence. The influence of various factors on rockburst failure under combined dynamic and static disturbance is analyzed by orthogonal test from both theoretical and numerical simulation perspectives. The results show that the amplitude of dynamic load is the key factor inducing rockburst in horseshoe tunnels, playing a dominant role in surrounding rock failure. The sidewall of shallow tunnel is more sensitive to dynamic loads. As the tunnel radius increases, the failure depth of the surrounding rock increases linearly, with the roof growing faster. A tunnel radius of 3–4 m is considered the optimal design range. Intact large-size rocks have a stronger ability to accumulate energy during rockburst, forming deeper burst pits and larger shedding rock blocks, resulting in higher rockburst intensity. The failure of surrounding rock decreases with increasing elastic modulus and increases with increasing buried depth, with the roof being less affected than the sidewall. When the lateral pressure coefficient is lower than 0.8, failure is primarily concentrated in the sidewall, while for coefficients higher than 0.8, failure is primarily concentrated in the roof. Under the same conditions, sidewall failure is more severe than roof failure. The tunnel radius and buried depth have a greater impact on sidewall failure, with smaller tunnel radius being more conducive to sidewall stability. The lateral pressure coefficient and buried depth have a greater impact on roof failure. Overall, sidewall failure is more severe than roof failure under the same conditions.