Effects of freezethaw on the determination and application of parameters of slope rock mass in cold regions

摘要

Freeze-thaw could significantly affect the deterioration of mechanical properties of slope rock mass, and should be taken into consideration when determining the parameters of slope rock mass in cold regions. In this paper, we first measured the freeze-thaw coefficient using the freeze-thaw cycle test on intact slope rock mass from Mengku Mine, then determined the freeze-thaw correction coefficient by taking field geological investigation and rock hardness into consideration, and established a linear relationship between Geological Strength Index (GSI) and Tianshan slope rock mass rating (TSMR) system (a rock mass classification method applicable in cold regions) by incorporating the freeze-thaw correction coefficient into the expression of rock mass effect. The results show that freeze-thaw correction coefficient varies between 0.71 and 0.93, and GSI varies between 45 and 63. We further determined the parameters of slope rock mass by employing the generalized Hoek-Brown criterion and using it established a numerical rock slope excavation model and analyzed the rock mechanic features and stability status. The results indicate that the maximum ground deformation of slop rock mass is 15 mm, and the floor rebound is about 42 mm. Overall, the method described in the present paper can be used to select slope rock mass in cold regions and calculate the slope rock stability.