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The need for better control of the adverse implications of blasting operations, especially blast-induced damage is of major importance. It determines the stability of excavations and has a major impact on for improving production efficiency, personnel and equipment safety and environmental concerns.A detailed experimental investigation was carried out to study blast-induced damage from small-scale blasts in a competent granodiorite rock formation. It employed small diameter boreholes (40mm) drilled to a depth of 6m. The blasts with 0.5--1.0 kg of explosive placed in the donor holes were surrounded by an array of monitor holes located at varying distances. A number of low-pressure pneumatic and high-pressure hydraulic sensors installed in receptor boreholes along with an acceleration station were used to monitor the time history of explosion pressure activity in the vicinity of the donor borehole. Interpretation of the magnitude and time history of the transmitted pressure yielded the extent of blast-induced damage. It was found that blast induced damage routinely propagated 16 blasthole diameters, and in some cases reached 29 blasthole diameters for short lengths of emulsion explosive in this rock type.
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1. Introduction. Growing interest in the topic addressed in this paper over the past few decades has led to several lines of research, such as identifying rock mass failure mechanisms and understanding their importance; estimating the extent of blast-induced damage (BID) in remaining rock mass from data collected in situ; developing predictive models to estimate the extent of BID; and Cited by: Field scale measurements of blast-induced damage are not common either, and are limited to specific rock types and conditions. Ouchterlony et al. ( & ) and Olsson et al. (), for example, have contributed with the study of blastinduced damage in rock by conducting crack measurements in granite blocks and bench by: 2. A sensitivity analysis of the modified model showed that the size of the blast-induced damage area is mainly affected by the following factors: rock mass properties, in . According to Sun, there are no less than 18 methods that have been proposed to predict damage due to rock of the methodologies to assess rock blast damage are based on numerical modeling, such as Blair, Ansys, Jaroslav, and few proposals are based on observations (empirical approach) from testing, including Esen et al., Olsson and Bergqvist, Olsson et al.
In this field little newer research has been undertaken to scientifically observe the onset of cracking, and there is a particular lack of information about which role the frequency content of the vibration plays. In this study the onset of blast induced cracking was observed in two instrumented test structures located in a rock quarry. The blast damage can easily extend few meters into the rock and the loosened rock can give rise to serious safety and stability problems to the surrounding rock mass of the underground openings. Reduction of shear strength due to blast induced rock movement, and Vibration induced displacement affecting slope stability or tunnel perimeter integrity Unwanted blast-induced damage assessment has a direct impact on safety, productivity, cost, and functioning of both surface and underground workings. In book: Rock Fracture and Blasting (pp) stemming a ﬀ ects the size of this damage zone in DSB blasts. As stem- Blast-induced dynamic rock fracture in the surfaces of tunnels.
1. Introduction. Blasting is an effective method for rock mass excavation in construction of nuclear power station. In the process of blasting excavation, blast-induced damage to surrounding rocks is detrimental to the rock mass integrity and engineering safety (Henrych, , Gao and Yang, ).Studies of the wave propagation characteristics and damage quantification in rock mass are of. Request PDF | On , P. Perazzelli and others published Empirical and numerical analysis of the blast - induced structural damage in rock tunnels | Find, read and cite all the research. rock, cut into manageable sizes, sprayed with penetrants (to make the blast-induced cracks traceable or visible) and crack parameters (length, quantity and pattern) investigated. The size and pattern of blast-induced damage were observed to depend on various parameters, namely; explosive parameters (explosive type, charge length, initiation. Blast fracturing increases with decrease in rock mass quality. Observations on exposed joint surfaces in open pit slopes indicate that the blasting process has induced varying forms of damage on these surfaces. Finite-discrete element numerical modelling of blast induced damage indicates that blast damage develops in different forms from the.