Analysis of Influence of Stress Lode Angle on Stability of Roadway Surrounding Rock

Abstract

Based on the variation range of the stress lode angle, the in situ rock stress is divided into σ v -type stress field, σ H -type stress field, and σ h -type stress field. Through theoretical analysis, the principal stress difference distribution law and plastic zone distribution pattern around the roadway in different types of stress fields are obtained. Theoretical and numerical simulation calculation results show that under different stress lode angle conditions, the principal stress difference distribution of the surrounding rock of the roadway is greatly different, which has a direct effect on the shape and range of the plastic zone of the surrounding rock of the roadway. In the σ v -type stress field and the σ H -type stress field, the shape of the plastic zone of the roadway surrounding rock is mainly oval and “butterfly,” while in the σ h -type stress field, the shape of the plastic zone of the roadway surrounding rock is mainly oval. The laboratory test proves that the stress gradient has an important effect on the damage degree of the surrounding rock of the roadway. The larger the stress gradient, the higher the strength of the rock mass and the more severe the damage. The change of the stress lode angle will affect the distribution law of the stress gradient of the surrounding rock of the roadway, thus affecting the degree of fragmentation of the surrounding rock. In type σ v and type σ H stress fields, the surrounding rock of the shoulder can be regarded as a key part of the roadway. In the σ h -type stress field, the plastic zones of the surrounding rocks of the roadway are more evenly distributed, and the damage range is less affected by θ. The influence law of the stress lode angle on the stability of the roadway has been well verified by field observation, and effective support measures have been proposed.