Experimental Study On Seismic Effect Of Deep-hole Bench Blasting In Open-pit And Its Numerical Simulation

The deep-hole bench blasting is used as the main production order in open-pit mining, and is also adopted as a main constructive method of rock and soil excavation in hydraulic and traffic engineering. By this way, the seismic effect resulting from blasting is inevitable. The control of seismic effect is concerned with not only the blasting quality, the slope constructive efficiency and the benefit of the construction, but also the stability of the slope rock and the safety of buildings around the slope. In order to reach the aim of controlling the seismic harmness, the seismic effect in blasting may be studied according to the used blasting method.In view of the production blasting in Sichuan Golden Summit Group limestone open-pit, the field experiments on seismic effect have been done. By measuring vibration velocities of particles in the ground, the blasting seismic waves' characters around have been studied and some shock absorption measures have been set. By analysing the change character of the vibration velocities of each step around, it is found that in the same distance, the explosive seismic effect of blasting step is about twice strong of lower step in the front, and the vibration velocities at the ground of the back are larger than those of the side. Through grey relational analyses, the primary and secondary relation of the multifactor of compartment which is concerned with the production of mine had been determined. Thereof, likely measure to shock absorption include: control the quantity of detonator, change charge design, adopt rational method of ignition and dilatory hour, rationally adjust the push heading ahead of the working face, etc.According to 700m bench in this limestone mine, the corresponding numerical model has been created with dynamic finite element method. By analysing the figure and field experiments on seismic effect, it is found that the figure is much close to field performance test at vertical direction. The rational model parameteris obtained, which is for analysing seismic effect of bench blast with finite element method. The numerical simulations analyses have been done. By studying the change character of the blasting seismic waves' along the vertical direction of the slope, it is found that the vibration velocities at the ground of the top of slope are larger than those of the bottom, to a certainty higher level up explosion platform. That is, there is the magnification effect of the vibration velocities.