Hoek-Brown强度准则在隧道岩体稳定分析中的应用研究

Application of Hoek-Brown Failure Criterion to Stability Analysis of Tunnel Rock Mass

Hoek-Brown强度准则适宜于描述完整岩石或节理岩体的破坏特征,并在岩体工程中得到了广泛应用。基于Hoek-Brown强度准则对某隧道工程岩体稳定进行分析,并与Mohr-Coulomb强度准则计算进行比较。结果表明:Hoek-Brown强度准则计算得到的关键点位移、塑性半径及塑性区范围均稍大于Mohr-Coulomb强度准则的结果;Hoek-Brown强度准则能够反映施工开挖扰动对岩体力学参数的影响。同时,假设施工扰动系数从隧道内向外逐渐减小,应用Hoek-Brown强度准则研究了开挖扰动程度对隧道塑性半径的影响规律。研究表明:随着扰动的增大,塑性半径非线性增大。

The Hock-Brown strength criterion is extensively used in geotechnical engineering field because it can describe the failure characters of integral rock or jointed rock mass. The stability of tunnel rock mass was analyzed by Hock-Brown and Mohr-Coulomb strength criterion respectively, and the results were compared. Results showed that displacements of key points, plastic radius and plastic zone size from Hock-Brown strength criterion were larger than those from Mohr-Coulomb strength criterion. Hock-Brown strength criterion reflects the effect of excavation disturbance on mechanical parameters of rock mass, which makes the analysis results more reasonable. Furthermore, based on the assumption that the disturbance coefficient gradually decreases from the inner wall to the outside of the tunnel, the regularity of excavation disturbance on plastic radius was analyzed by using Hock-Brown strength criterion. Result showed that plastic radius increased nonlinearly with the increment of excavation disturbance coefficient.