Blasting Effect Research Of Tunnel Energy Gathering Blasting Tube And Its Engineering Application

At present,the phenomenon of over-excavation and under-excavation widely exists in highway tunnel construction,and the traditional smooth blasting has been unable to meet the needs of development due to the increasing requirements of blasting effect in engineering projects.Therefore,in highway tunnel excavation,the phenomenon of over and under-excavation must be effectively controlled.Previous studies have shown that cumulative hydraulic smooth blasting technology has positive effects on reducing project cost,improving smooth blasting effect,as well as improving operation environment.Therefore,in order to have a further analysis of the effect of tunnel cumulative hydraulic smooth blasting and its internal mechanism,this paper takes Wen Xu Tunnel in Guangxi Province as the engineering background and through the combining research methods of numerical simulation,field test and field examination,it analyzes the influence on the rock caused by the D type,W type and slitting energy gathering blasting tube blasting--the three kinds of blasting commonly used in engineering blasting and the conventional blasting.The influence of the different axial uncoupling coefficient on the blasting effect is also studied and the corresponding blasting parameters are at the same time optimized in this paper.Combined with testing analysis and field experiment,this paper finally carries on the induction of the advantages of cumulative hydraulic smooth blasting.This study mainly includes the following work and the following achievements:(1)By setting up the single-hole blasting geometric model and carrying on analysis and research on the model,it is concluded that for peripheral hole blasting,the blasting effect of D type energy gathering blasting tube is the best,followed by W type and then the slitting energy gathering blasting tube,in terms of crack propagation law of rock mass caused by blasting,stress and time analysis and the effective plastic strain of rock.Conventional blasting effect is the worst of all.(2)Numerical simulation is carried out on the charging structure of the peripheral hole,and the influence of different axial uncoupling coefficient on peripheral hole blasting is analyzed.It is concluded that the blasting effect of the peripheral hole is the best when the axial uncoupling coefficient K1 is 2.0.In addition,establish a full-section blasting geometric model based on the optimized blasting parameters,analyze the feasibility of the optimized blasting parameters,and obtain the feasibility of the optimized blasting parameters through the analysis of the blasting results.(3)Through field tests and studies,it is found that when optimized cumulative hydraulic is used for smooth-surface blasting,the maximum over-excavation is 26.6%less than that of conventional blasting in the early stage and in addition,the number of single-cycle gun holes is reduced by 46,which significantly increased the labor rate.