The influence of the heterogeneity of rock mass for surrounding rock stability evaluation of a tunnel

摘要

In this study, we reviewed the influence of various heterogeneity factors of rock mass on the displacement of the tunnel. Wederived the critical deformation formula and proposed the stability evaluation method via the elastoplastic analytical solutionof a circular tunnel. The traffic tunnel of the Sanhekou hydro-junction project was taken as an example to establish theheterogeneous rock mass finite difference method model. A new method is proposed to obtain the most basic heterogeneousrock mass parameters, and evaluated the stability of the heterogeneous rock mass tunnel. The results showed that whenthe weak interlayer is randomly distributed, the deformation of the wall increases with the decrease in the average valueof the parameters, and it is significantly affected by its standard deviation. The core of the stability evaluation process ofthe heterogeneous rock mass tunnel is to obtain the radius of the plastic zone and the distribution of weak interlayer. If thedistribution characteristics of the interlayer are not determined, the critical deformation may be appropriately reduced by15% to evaluate the stability of the tunnel. We also verified the reliability of the stability evaluation method by monitoringthe 2# diversion tunnel of the Zipingpu hydraulic project.