Gupta, R.N. and Pal Roy, P. and Bagchi, A. and Singh, B. (1987) Dynamic effects in various rock mass and their prediction. Journal of Mines, Metals & Fuels, 35 (11). pp. 455-462. ISSN 0022-2755

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Abstract

Dynamic effects in terms of ground vibrations due to blasting are an undesirable side-effect of the use of explosives to fragment rock for mining, excavation, quarring, and construction. When an explosive charge is detonated in a blast hole, large volume of gas is released instantaneously at high temperature and pressure producing shock waves and heaving effects during rock breakage. The energy liberated is only partially utilsed for breaking the rock and a part of the energy is transmitted to the surrouding rock mass in the form of elastic and or seismic waves. The seismic energy or ground vibration is usually described as a time-varying displacement, velocity or acceleration of a particular point in the ground. The paper describes in detail, the results and findings of statistical analysis of data recorded during blasting in various rock mass in situ including limestone (fissured and highly jointed), sandstone-alluvium, iron ore, basalt (closely jointed), sandstone (weathered), dolomite and granite (hard and fresh, soft and weathered, hard and soft mixed). The analysis considered nine different forms of empirical relations in predicting ground vibrations by blasting. The relations include a general form and inelastic attenuation. For a better understanding of the relations, all ‘simple’ and ‘partial’ regression coefficients as well as ‘simple’ and ‘partial’ correlation coefficients are obtained by the regression analysis of two independent variables. Numerical computations are done using a micro-computer. The required amount of specific charges are obtained for a wide range of peak particle velocity and distance of the measuring transducer. Important discussion are also included with a view to predict dynamic effects. A few relations were suitable for certain rock mass whereas other were unsuitable. The controlling factor was the nature of rock mass. In authors’ view the findings would be helpful in designing blasting patterns to protect nearby structures. Case studies and results obtained are included in the paper.

Item Type:	Article
Subjects:	Blasting
Divisions:	UNSPECIFIED
Depositing User:	Dr. Satyendra Kumar Singh
Date Deposited:	17 Mar 2012 06:19
Last Modified:	14 Jul 2012 11:21
URI:	http://cimfr.csircentral.net/id/eprint/1073

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