Abstract
Rock damage and vibration attenuation are the basis of blasting design, which will affect rock breaking results and the safety of structures (buildings). In this paper, the effect of blast-hole arrangement, delay time, and decoupling charge on the rock damage and the vibration attenuation in multihole blasting were numerically investigated. Through dynamic analysis software ANSYS/LS-DYNA, the JOHNSON_HOLMQUIST_CONCRETE (JHC) rock model and fluid-solid coupling method were used to establish single-hole and multihole rock blasting models. Based on the analysis of single-hole rock damage and vibration, firstly, the effect of the above three factors on the rock damage characteristics of multihole blasting was analyzed. Then, the extracted peak particle velocity (PPV) data of multihole blasting were fitted to the United States Bureau of Mines (USBM) equation to obtain the blasting vibration attenuation parameters (the site constant K and α). It is found that the blast-hole arrangement, delay time, and decoupling charge have a much smaller effect on α than K. At the same time, a delay-time-dependent model of PPV correction coefficient was proposed, and its rationality was verified by field data. The results obtained in this paper have reference significance for optimizing the blasting design and improving the blasting effect.
Highlights
As an important construction method, engineering blasting is widely used in production and construction activities such as mining engineering, hydraulic engineering, tunnel engineering, and nuclear power engineering [1]
E range of the near zone of the blasting source is affected by the lithology, explosive performance, and blasting methods, and it is estimated to be approximately 2–33/100 times the charge radius [2]. e near-zone damage characteristics caused by the explosion have an important influence on the subsequent grinding, crushing, or slagging efficiency and energy utilization. e remaining part of the explosion energy will be dissipated in the form of shock waves, thermal energy, and blasting seismic waves, accompanied by adverse effects such as vibrations, shock waves, fly rocks, toxic gas, and noise [3]
A calculation equation of peak particle velocity (PPV) correction coefficient with delay time as the independent variable is proposed, and the rationality of the equation is verified by field data. e blasting vibration parameters and PPVs of different numbers of blast-holes are compared. e following conclusions are obtained
Summary
As an important construction method, engineering blasting is widely used in production and construction activities such as mining engineering, hydraulic engineering, tunnel engineering, and nuclear power engineering [1]. Based on field tests and numerical simulations, Li et al [15] studied the explosive load characteristics, the blast-induced damage characteristics for rock mass, and the PPV attenuation law and established the relationship between PPV at 30 m away from the charge hole and the damage depth of rock mass. Blasting with decoupling charge can greatly reduce underexcavation, overexcavation, and side pumice, improve construction efficiency, and have an important effect on rock damage and blast-induced vibration. Existing studies have used the methods of theoretical analysis, field test, numerical simulation, and model test to study rock blasting damage and blast-induced vibration. Numerical simulations were carried out, and the results of single-hole blasting rock damage and vibration were taken as comparison standards to analyze the influence of hole arrangement, delay time, and decoupling charges on the blasting effect
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