Study On Shaped Charge And Effect Of Condensing Water Pressure Blasting In Large-section Tunnel

With the improvement of the requirements for blasting effect,the traditional smooth blasting method can not meet the needs.Therefore,how to better control the over-under-excavation in the tunneling process has become a direction of current research.By studying the condensing water pressure blasting technology,it has important engineering significance to improve the smooth blasting effect,reduce the surrounding rock damage,save the project cost and improve the working environment.In order to study the mechanism and effect of large-section tunnel shaped water blasting blasting,this paper analyzes the wall thickness and slit width of the collecting tube by theoretical analysis,numerical simulation,field test and on-site detection.The influence of the coupling condition with the explosive on the stress state of the rock and the stress state of the peripheral eye in the presence or absence of the shaped tube,combined with the field test and detection,analyzed the advantages of the shaped water blasting.The main work and results of this paper are as follows:1.By establishing a single hole blasting geometric model,when the slit width of the shaped tube is 4mm,the wall pressure of the blasthole at the slit is the largest,indicating that the optimal slit width is 4mm;When it is 3mm,the wall pressure of the blasthole at the slit is the largest,indicating that the optimal wall thickness is 3mm;when the energy of the energy collecting tube and the explosive is coupled,the rock breaking efficiency is higher than that of the concentrating tube and the explosive.2.Based on the numerical simulation of the two-hole non-polymerization tube and the numerical simulation of the double-hole polycondensation tube,the stress wave propagates uniformly in the form of concentric circles after the detonation of the charge tube without the energy-generating tube;The shaped energy jet from the slit reaches the surface of the blasthole,causing stress concentration,which provides an initial prerequisite for generating the initial crack.3.When the adjacent blastholes of the tunnel perimeter are simultaneously detonated,the concentrating blasting enhances the superposition of the stress field at the blasthole connection,which is about 1.4 times that of the condensed tube without condensing,which is beneficial to the formation of through cracks between the blastholes.4.Through field test of condensing water calendering blasting,the maximum over-excavation amount of condensed water calendered blasting is reduced by 25%compared with the previous conventional blasting over-excavation;the average over-excavation area of??condensing water calendered blasting Compared with the traditional blasting in the previous period,it decreased by 46.8%.Compared with the traditional smooth blasting,the energy-saving blasting of the condensing water reduced the amount of wet-spraying concrete by 3.2m~3 per metre.5.Due to the water“water wedge”effect and“water atomization”effect in the water bag,the dust content in the air after blasting is greatly reduced,which ensures the health of the construction workers.The ventilation time after blasting is reduced by 10 minutes,and the large slag is reduced.Significantly improved labor efficiency.6.After the water pressure concentrating smooth blasting,the number of eyes in the single cycle is reduced by 10%,the detonator consumption is reduced by 10%,the explosive consumption is reduced by 27%,and the concentrated water blasting blasting is saved compared with the traditional smooth blasting.1589 yuan,achieved good economic results.