(1. State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan，Hubei 430072，China；2.Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Ministry of Education，Wuhan University，Wuhan，Hubei 430072，China)
Abstract：Blasting excavation is one of the significant factors which would lead to cracking even instability of jointed rock mass of slope. Based on fracture dynamics mechanics，this paper explores the disturbance of blasting excavation on crack growth in slope rock mass and analyses the effect of in-situ unloading under excavation disturbance and explosion stress wave on stress intensity factor of crack tip and growth mode of cracks. Results show that both of the explosion stress wave and geostatic stress determine the growth mode of cracks in slope rock mass. The growth mode of cracks is mainly I-II compression-shear under in-situ stress. The unloading effect caused by blasting excavation would change the condition of in-situ，which transforms the mode from I-II compression-shear to I-II tensile-shear，therefore increases the risks of crack growth and the cracks become more likely to grow with the rise of unloading degree. The explosion stress wave also increases the risks of crack growth.
2015, Vol. 34 
