Based on the concept of extruded surrounding rock,the stability of surrounding rock was evaluated using the safety factor method of surrounding rock expressed by shear strength.The expres-sion of safety factor of surrounding rock expressed by stress partial tensor was derived.The numerical expression of safety factor of surrounding rock was realized through the secondary development of FLAC3D.The influence of deformation grade and cross-sectional shape on the stability of surrounding rock was discussed,and the influence of grouting reinforcement on the stability of surrounding rock was studied.The results show that compared with the plastic zone evaluation method,the surrounding rock safety factor method can realize the quantitative evaluation of the failure degree of surrounding rock at any position;The failure boundary of surrounding rock is in butterfly-shaped distribution;The larger the cross-sectional area of the tunnel is,the greater the damage range of the surrounding rock is;The closer the tunnel is to the circle,the smaller the relative failure range of the surrounding rock is,and the circle is the optimal cross-sectional shape;The improvement effect of advanced grouting reinforcement on the stability of surrounding rock is better than that of radial grouting reinforcement.The research results provide a reference for the structural design and construction deformation control of extruded surrounding rock tunnel.
关键词
挤压性围岩隧道/围岩安全系数/围岩稳定性/变形分级/注浆加固
Key words
extruded surrounding rock tunnel/safety factor of surrounding rock/stability of sur-rounding rock/deformation classification/grouting reinforcement
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