Study On Application Of Slope Cutting Technology In The Tunnel Excavation

This paper, which is based on the blasting excavation of the Huaguo mountain tunnel in the Hubei-Enlaienqian Highway, adopts the method of theoretical analysis,field experiment and numerical simulation to determine the reliability and practicability of slope cutting blasting technology in the tunnel. We also obtain that best method for Ⅳ level of surrounding rock blasting is large slope cutting technology. But to Ⅱ,Ⅲ level, because of its high resistance line and hard rock, we need to add some small slash, about 4 or 6 shallow boreholes, in the middle to eliminate the " clamping force " between the foundation rock.This is called slotting technology of Large and Small slope. At the same time,we analysis the angle of cutting hole and come to a conclusion that the best angle is 70°.At the end, my paper fed the numerical simulation results back to engineering practice, then we obtain a best method in the tunnel excavation construction:(1) At first,this paper expounds current research status and existing problems of slope cutting technology in the tunnel, and indicates that the cutting technology can effectively improve the utilization rate of explosives and blasting energy and obtain good cutting effect. Finally, these aspects lead to to the topic of this article.It is“the application and research of slope cutting technology in the tunnel excavation” and then these aspects expounds the purpose and significance of this study.(2) Through the mechanism of rock blasting classification, the rock blasting, rock blasting internal and external effect, slope cutting technology mechanism, cutting parameters and so on in detail, these aspects provide a theoretical basis for the research of this paper.(3) ANSYS14.5/LS-DYNA finite element software is used to establish the numerical model and we need different cutting methods for different level of rock excavation. The results show that the rock blasting effect by large slope cut technology is good for Ⅳ level of surrounding rock excavation and we need add short blasting hole for Ⅱ,Ⅲ level of surrounding rock excavation.(4) We establish three different numerical models. The cutting angle is 60°,70°,80°. Through the analysis, we determine that blasting effect of 70° angle is best.(5) We feed the numerical simulation results back to engineering practice to verify the accuracy of the numerical simulation results. Results show that blasting effect is good by the the results of the three or four chapter optimal conclusion. It is concluded that the results of numerical simulation is feasible. We obtain a economic and efficient cut blasting technology for the highway tunnel excavation.(6) Based on the theoretical analysis,field test,numerical simulation and so on, we point out the problems and difficulties existing in the research work. This paper fed the research outcome back to the engineering and then form a new comprehensive and practical cut blasting technology and provide a reference for blasting design.