Showing papers in "Engineering Blasting in 2014"
Journal Article•
TL;DR: In this article, the dynamic compression mechanical properties of granites under different gas pressures were investigated using Split Hopkinson Pressure Bar (SHPB), and the stress-strain characteristics and failure process of the rock material were discussed.
Abstract: The dynamic compression mechanical properties of granites under different gas pressures were investigated using Split Hopkinson Pressure Bar(SHPB),and the stress-strain characteristics and failure process of the rock material were discussed.The testing results showed that there had an obvious fitting relationship between the average strain rate and the impact pressure,and the time-history curves of strain showed significantly difference under various impact pressures;the rock stress-strain curve could be divided into four stages,and the impact pressure had a reasonable value that demonstrated impact on the broken rock;the damage forms of fracturing presented an axial cleaving mode as the major and crushing mode under the high impact pressure.
1 citations
Journal Article•
TL;DR: Based on a number of urban pit controlled blasting practice, the characteristics of urban controlled blasting excavation and the influencing factors of safety were summarized and a summary and reflection were put up from different angles including undertaking the projects,the safety costs of inputs, construction methods and means, and management system of the project for the controlled blasting safety construction of city foundation pit under complex environment as discussed by the authors.
Abstract: Based on a number of urban pit controlled blasting practice,the characteristics of urban controlled blasting excavation and the influencing factors of safety were summarizedAnd a summary and reflection were put up from different angles including undertaking the projects,the safety costs of inputs, construction methods and means,and management system of the project for the controlled blasting safety construction of city foundation pit under complex environmentIt could provide a reference for similar projects
1 citations
Journal Article•
TL;DR: In this paper, a prediction model of the blasting vibration velocity of existing tunnel was established using BP neural network, which was compared with a variety of empirical formulas, and the results indicated that the prediction data of blasting vibration were in a good coincidence with experimental data,BP neural network had characteristics of fewer error and high accuracy.
Abstract: Based on Nanjing airport line metro project,field monitoring tests were carried out on existing tunnel vibration response induced by blasting excavation of adjacent tunnel.A prediction model of blasting vibration velocity of existing tunnel was established using BP neural network,which was compared with a variety of empirical formulas.The results indicated that the prediction data of blasting vibration velocity by BP neural network were in a good coincidence with experimental data.Compared with empirical formula,BP neural network had characteristics of fewer error and high accuracy.The research could provide a theoretical reference for controlling blasting vibration of existing tunnel induced by blasting excavation of adjacent tunnel and improve blasting excavation program of new tunnel.
1 citations
Journal Article•
TL;DR: In order to prevent the phenomenon of "blasting and not collapse", two feasible blasting programs of block disintergration and cutting blasting were made and the stress distribution was analyzed as mentioned in this paper.
Abstract: The original bridge had to be removed by blasting due to the road to be extended from Luoyang to Sanmenxia in Lianhuo highway.It's a bridge of door structure which containing intensive reinforcement in the main bearing component.In order to prevent the phenomenon of "blasting and not collapse",two feasible blasting programs of block disintergration and cutting blasting were made and the stress distribution was analyzed.Comparing with the two programs,the technology which combination of cutting by collecting energy and drilling blasting was used.Because of making the corresponding pretreatment measures and strict safety protection measures,an ideal blasting effect was achieved.It provided a reference for the similar projects.
1 citations
Journal Article•
TL;DR: In this paper, the authors used a high-speed camera to study the nonel tube detonation reliability under different special circumstances, including single broken hole and continuous broken hole nonel.
Abstract: Indoor laboratory experiments of the nonel tube detonation propagation reliability under different special circumstances had been conducted by using high-speed photography.The special circumstances included single broken hole nonel and continuous broken hole nonel.The average velocity of the normal nonel tube using in the test was 1750m/s.Through the observation and calculation analysis of the slow motion picture taken by the high-speed camera,the results showed that after the nonel's pipes were destroyed caused by broken holes,for single broken hole nonel,the maximum length of half-broken groove to maintain a reliable propagation was 15mm,and it may propagate successfully or maybe not when the length of half-broken groove was between 15mm and 30mm,the chance of propagating successfully decreased with the increased of half-broken groove′s length.When the length of half-broken groove exceeded 30mm,it would fail to propagate certainly.The delay time caused by 20mm single broken hole was 195μs at least.For continuous broken hole,the larger of the half-broken grooves′length and density,the lower reliability of the detonation propagation,and the overall delay time caused by 3continuous 5mm length half-broken groove was 255μs.The test conclusions can provide references and reasonable recommendations for the network connection on blasting construction site.
1 citations
Journal Article•
TL;DR: In this paper, domestic and foreign research on the open-pit bench blasting of millisecond delay interval time was analyzed from the aspects of improving fragmentation effect and vibration reduction, which brought much confusion to the users; while majority of domestic scholars gave the experience value based on engineering practice.
Abstract: The domestic and foreign research on the open-pit bench blasting of millisecond delay interval time was analyzed from the aspects of improving fragmentation effect and vibration reduction.Based on the study of improving fragmentation effect,foreign scholars mostly proposed formulas with different parameters,which brought much confusion to the users;while majority of domestic scholars gave the experience value based on engineering practice.Based on the research on vibration reduction,foreign scholars proposed different calculation methods,but their results had certain limitations;domestic scholars gave the optimal range according to the engineering practice.The direction of future research on open-pit bench blasting interval time was also forecasted,which could provide a reference for the blasting workers.
1 citations