Application Research Of Broken Surrounding Rock Cutting And Concentrated Water Pressure Smooth Blasting Technolog

Drill and blast method because of its simple operation,low construction costs and is widely used in mining shafts,tunnel excavation and other projects.In the tunnel drilling and blasting excavation process,light surface blasting is necessary to control the contours of over-under excavation,affecting the stability of the excavation surrounding rock and construction safety,while tunnel blasting excavation instantly produces a large amount of dust seriously affect the health of the construction personnel.In this study,in view of the problems of fractured surrounding rocks,poor light blasting excavation effect and large dust concentration generated by blasting in Meng Province tunnel,the technique of tangential polyenergy hydrodynamic light surface blasting is proposed.This technology is based on adjusting the explosive blast energy distribution to strengthen the cracking effect of energy on the rock in the direction of tangent,which is a new technology of rock directional fracture control blasting,effectively improving the effect of light surface blasting,improving the stability of surrounding rock,reducing the concentration of blasting dust,and achieving the purpose of safe,green and efficient tunneling construction.In this paper,we have carried out research related to slit polyhydrodynamic light surface blasting technology based on the research of slit pack directional fracture control blasting technology,and the main findings are as follows:（1）Based on blasting theory,comparative analysis of the slit pack,conventional charge blasting mechanism,further elaborated the slit pack directional fracture control blasting technology on the control of the blast product mechanism,that is,in the direction of the slit opening has a certain"concentrated energy"effect,can achieve the directional fracture control blasting of the medium,to improve the effective utilization of explosive energy in the direction of the slit.The results of the analysis of the factors affecting the blasting effect of the slit package show that the radial uncoupling factor has a significant effect on the controlled blasting effect of its directional fracture.（2）Dynamic focal dispersion test and blast damage fractal dimension calculation analysis of slit pack blasting show that the best effect of slit pack directional fracture control blasting is achieved when the radial uncoupling coefficient is 1.71,with the longest extension distance of16.3 cm for the main crack and one secondary crack,and the peak stress intensity factor at the tip of the left main crack reaches 2.6 MN?M^-3/2,and the energy in The energy is strongly concentrated in the direction of the cut.By comparing the degree of damage to the medium after the tangential package and conventional charge blasting under this factor condition,the damage to the medium in the non-tangential direction of the former is reduced by 35%,and the damage to the medium in the tangential direction is increased by 40%.Under the effect of tangent tube restraint,the explosive energy in the tangent direction to strengthen the fracture of the media,in the non-tangent direction to play a certain protective effect on the media.（3）Compared with conventional charge blasting,when the radial uncoupling coefficient of perimeter hole charge is 1.54,the field application study of slit pack blasting shows that compared with conventional charge blasting,the slit pack blasting technology can increase the feed of one blasting cycle by 0.4m,increase the utilization rate of gun hole by 12%,and reduce the explosive unit consumption of one cycle by 0.1kg/m³;the perimeter hole distance is enlarged from55cm～65cm to 70cm～100cm,21.5%～35%,the tunnel surrounding rock is excavated smoothly,the half-hole rate reaches 93%,the contour line is controlled better,the average over-excavation is reduced by 80.7%;the spraying volume of one cycle is reduced from 52.76m³/m to 41.36m³/m,21.6%,and the spraying time is shortened by 35min.（4）The field application study of tangential poly-energy hydro-pressure blasting shows that the perimeter holes are charged with tangential poly-energy hydro-pressure blasting structure,and the auxiliary holes and hollowing holes are filled with water bags.The application results show that the average dust concentration after hydraulic blasting is reduced by about 35.4%compared with conventional blasting,the time to maintain the dust concentration at the peak of1000mg/m³ is shortened by 10min,the time to exceed the alarm value of 500mg/m³ after blasting is reduced by 11min,and the site construction environment is improved;the perimeter hole half-hole rate reaches 94%,and the maximum over-excavation is reduced from 110cm to The half-hole rate of peripheral holes reached 94%,the maximum over-excavation was reduced from110cm to 10cm,a reduction of 91%,the average over-excavation was reduced from 69cm to 8cm,a reduction of 88%,the wall excavation flatness was high,the stability of the surrounding rock was improved and safe construction was guaranteed.It has achieved high efficiency excavation and improved the tunnel construction environment,which has significant advantages compared with conventional blasting.