Abstract：Ultimate deformation of tunnel surrounding rock has been regarded as a critical index for evaluation of surrounding rock stability. This study attempts to work on the approach to the tunnel surrounding rock ultimate deformation. This approach relies on an assumption that the rock mass materials obey the H-B criterion，according to the mechanical characteristics of weak rocks as well as their response mechanism to excavation. Based on this assumption, the radius of loose region，generated within the surrounding rock of circle tunnels，is formulated. Next，this formulation is combined with Rabcewicz?s initial instability mode，attaining a method of computing support resistance that is required to stabilize the tunnel. Furthermore，the approach is established to calculate the ultimate deformation of tunnel surrounding rock. This established evaluation approach is validated through a comparison to numerical data provided by existing studies. Parametric analysis is also conducted，investigating the effect of rock mass properties and of tunnel geometric parameters on the ultimate deformation/strain of tunnel surrounding rock. It reflects that the tunnel surrounding rock ultimate strain has relatively high sensitivity to far-field stress，unconfined compression strength and H-B constant，while that is low in terms of intact rock Young?s modulus，Poisson?s ratio and tunnel radius.
苏 雅，苏永华，赵明华. 基于Hoek-Brwon准则的软岩隧道围岩极限变形估算方法[J]. 岩石力学与工程学报, 2021, 40(S2): 3033-3040.
SU Ya，SU Yonghua，ZHAO Minghua. An evaluation approach to ultimate deformation of tunnel surrounding rock in weak rocks based on the Hoek-Brown criterion. , 2021, 40(S2): 3033-3040.
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2021, Vol. 40 
