Influence Of Blasting Vibration On The Stability Of Slope With Structure Planes

Rock mass is a discontinuous, anis otropy, heterogeneity structure, whic h random dis tributes many structure planes including faults, joints and fracture zone s.The slope rock mas s of Zuangou open-pit mine containe gray limestone and black with fli nt limest one, this two kind of limes tones obviously c ontaine wit h structure planes. Because of structure plane and the freque nt mining blasting, i ts stabilit y has become an important fac tor which c onstraining the safety and production of mine.Therefore, it's ne cessary to study the infl uence of blasti ng vibration on the st abil ity of slope.The geological investigat ion, phys ical and mechanical propert ies tests of roc k mass and experiments of blasting vibration wer e carrie d out at the blasting engineering of Zuangou open-pit mine. The blasting vibration s ignals were analyzed with t he methods of wavelet packet. Moreover, LS-DYNA software was used to si mulate the blasting of mine as well as analyzed the impact of structure planes on the dynamic sta bility of slope. The whole resea rch works ar e as followed:(1) The distribution of s tructure plane i n the slope rock mass was obtained through the geological i nvestigation on site. The structure planes are down-slope direction, and t he horizontal angle is 70.(2) The result s of blasting vibration showed that when the seismic wave passed through t he structure planes, the particle pe ak velocities of blasting vibration was obvious ly attenuated, its average attenuation rate was 48.59 percent. However, the seismic wave was n't passed t hrough the structure planes, the particle peak ve locitie s of blasting vibration was generally attenua ted. Results from wavele t packet anal ysi s showed that the seismic wave passed t hrough the structure planes made the proportion of the energy of higher-frequency signal decreas ed, and the proportion of the energy of lower-freque ncy signal increased.(3) The results of numerical simulation showed that when the seismic wave passed t hrough the struct ure plane s, the particle peak velociti es of blasting vibration was obvi ously attenuated, its average attenua tion r ate was more t han 50 pe r cent.Compared t he numer ical simulation r esults wi th field testing results, we found that when t he seismi c wave passed through the structure pla nes, the average a tte nuationrate of field testi ng was about 48.59 percent, and the average attenua tion rate of numerical simulat ion was about 56.29 percent, the relative error was about 9.68 percent. And the law of numerica l si mulation results was consistent with the field testing results from wavel et packet a nalysis.(4) When the dista nce of the center from the center of blasting source increased from 20 m to 40 m, t he diameter of the hole decreased from 160 mm to 90 mm, the holes of bl as ting from three to one hole, the delay times i ncrease d from 25 ms t o65 ms a nd pr e-splitting blasting, t he infl uence of blasting vibration on the st ability of sl ope decreased. Thus, it need the vibration reducing measures of sma ll hole blasting ? hole by hol e blasting ? 65 ms millis econd delay blasting and pre-s plitting blasting to make sure of the stability of the slope.(5) The correl ati on degree of blasting vi bration characteristic parameters and the blasting condition was analyzed by using the path coefficient analysi s method.When we ne ed to cont rol the par tic le peak ve locitie s, conside r the blasting distance and blasting charge. Whe n we need to control the fr equency of blasti ng vibration,consider the blasti ng distance and t he rock complet e coefficient.(6) I n order to promis e the stability of the slope under the blasting load,combine t he sa fety criterion of vel ocit y of blasting vibration; propose scientific and rational bl as ting vibrat ion control measures when dea ling with the near slope blasting. The nomora l bla sting parameter and pre-splitting blasting paramete r were designed which can promise t he stabili ty of the slope.According t o the above resea r ch, t he i nfluenc e of different blasting loads on the sl ope st abil ity with structural plane was obtained, proposed scient ific and rational blasting vibr ati on control measures,promi sed the stability of the slope.