The Research Of Blasting Seismic Effect Controlling With Precise Time Delay Technology Nearby Slope

With the high-speed development of national economy, a lot of artificial steep slopesderived from blasting excavation of geotechnical engineering, and the costs and difficultyof slope maintenance becomed much bigger. However, the slope stability is theprecondition of the outdoor safety production, so there is very important theoretical andpractical significance to carry out the dynamic response research of the high and steepopen pit slope, analysis rock damage mechanism under blasting load, seek effective wayof controlling blast seismic hazards, strengthen the relevant application research of digitalelectronic detonator and promote the blasting technology more precise, digital andscientific.The paper combined with electronic detonator and YiBo initiation system, based onblasting excavation of controlled blasting with precise delay time interval nearby theslope, the means of theoretical research, model test, numerical calculation and fieldapplication were used to deeply analyze propagation attenuation rule and effect ofseismic wave caused by control blasting with precise delay time interval, optimizingmethod of delay time interval between blasting holes, rock blasting damage, slopeblasting vibration response and so on. The main work is as follows:(1) A new blasting vibration duration prediction formula is given, the predictionaccuracy is improved through introducing signal energy(Es) into predictive formula. Theresults prove that, the duration is negatively related to the proportional velocity(Vmax/R)and positively related to the proportional charge weight(Q1/3/R). In the case of a certainexplosive section number, the superposition is more serious, the signal energy improvesprediction accuracy much higher.(2) The frequency domain details characteristics of controlled blasting with precisetime delay are fully revealed by wavelet packet decomposition of signal energy. Theresults show that, with the increase of propagation distance, the energy of high frequencyband decays fast and predominant frequency of energy focus on the low frequency band. Signal energy mainly concentrate in the frequency range of0~300Hz, which can bedivided into multiple sub-frequency band. Under the action of damping ditch, decreasingamplitude ratio of peak vibration velocity and energy reach more than40%and60%respectively, and average decrease rate of radial and tangential strain on slope surfacereach49.4%and35.2%respectively. The maximum radial and tangential stress on theslope surface value from2.26MPa and1.16MPa to0.84MPa and0.95MParespectively.(3) Based on theoretical analysis, numerical analysis and experimental research,according to the different blasting environment, objectives and requirements, three kindsof calculation method for optimizing reasonable millisecond delay time are provided.Especially the method based on theory of energy distribution for explosive material,which can realize the interference cancellation of seismic waves, reduce the blastingseismic intensity and improve the blasting effect of rock mass. At the same time thismethod is not affected by the quality and the space position explosive cartridge.(4) Acomplete set of experimental study system made up of high-speed photographytechnology and the dynamic strain test system is established. The integration andautomation of blasting test is realized under the condition of multiple parameters, the keytest technological problem of controlled blasting with precise time delay is resolved. Thecalculation method of blasting damage based on ultrasonic wave measurement isperfected, and the control measures of damage are proposed from two aspects of blastingenergy and the energy transfer process.(5) The spectrum analysis of blasting vibration signal is done through seismicresponse spectrum analysis technology, the influence law to structure dynamic effect ofblasting vibration caused by controlled blasting with precise time delay is revealed. Thevibration response analysis method of controlled blasting with precise time delay basedon mode combination method of CQC is proposed, the dynamic effect evaluation resultsof slope deviates from the actual situation because of the unequal sex of each order modalresponse is resolved. The results show that, the total effect values of velocity and standard velocity decrease at first, then increase gradually, and decrease slowly at last,there is a minimum for both of them. So, choosing of reasonable time delay shouldcomprehensive consider blasting vibration intensity, blasting effect of rock mass anddynamic response of construction.The results of experimental study and engineering application show that: theproposed predictor formula for duration of blasting vibration has high accuracy, which isfeasible to predict duration of blasting vibration. The method based on theory of energydistribution for explosive material is more active and flexible when the explosive holeand segment explosive quantity are setting, and the calculation method is simple, socompared with other two methods, the method based on theory of energy distribution forexplosive material is more convenient for engineering application. The establishedexperimental study system can conduct multi-faceted, multi-parameter dynamic real-timemonitoring for process of crushing rock, and it’s feasible to optimizing the blastingparameter. The vibration response analysis method of controlled blasting with precisetime delay based on mode combination method of CQC can make the dynamic evaluationresult of the slope more reasonable and objective, which is more consistent with theactual situation.