Theoretical analysis of grouting reinforcement of surrounding rock with strength drop in deep chamber

Excavation disturbance of deep chamber can easily cause the broken and deterioration of surrounding rock, bringing hidden danger to construction safety. Based on post-peak strength drop model, considering the influence of grouting seepage force, the analytical solutions of stress and displacement of surrounding rock in deep circular chamber before and after grouting were deduced by using orthogonal non-associated flow rule. Then, the evolution laws of stress and displacement with different chamber depths, radii and grouting thicknesses were analyzed in detail. Finally, the correctness of the theoretical solutions was verified by an engineering field. Results show that grouting has a good modulating control effect on the stress contribution and displacement of the surrounding rock, while on the magnitudes of the stress is not obvious; the influence of chamber depth on the stress and displacement of surrounding rock is significant, while chamber radius and grouting thickness is insignificant.