The blast-induced ground vibration prediction using scaled distance regression analysis is one of the most popular methods employed by engineers for many decades. It uses the maximum charge per delay and distance of m...The blast-induced ground vibration prediction using scaled distance regression analysis is one of the most popular methods employed by engineers for many decades. It uses the maximum charge per delay and distance of monitoring as the major factors for predicting the peak particle velocity(PPV). It is established that the PPV is caused by the maximum charge per delay which varies with the distance of monitoring and site geology. While conducting a production blasting, the waves induced by blasting of different holes interfere destructively with each other, which may result in higher PPV than the predicted value with scaled distance regression analysis. This phenomenon of interference/superimposition of waves is not considered while using scaled distance regression analysis. In this paper, an attempt has been made to compare the predicted values of blast-induced ground vibration using multi-hole trial blasting with single-hole blasting in an opencast coal mine under the same geological condition. Further,the modified prediction equation for the multi-hole trial blasting was obtained using single-hole regression analysis. The error between predicted and actual values of multi-hole blast-induced ground vibration was found to be reduced by 8.5%.展开更多
Large-scale BF is the tendency of domestic and foreign Iron-making technology.Due to the limit of resource,technology and equipment,we can not reach the planned goal after putting the big BF into production,it is of g...Large-scale BF is the tendency of domestic and foreign Iron-making technology.Due to the limit of resource,technology and equipment,we can not reach the planned goal after putting the big BF into production,it is of great significance to explore the key technologies again for the sound development of the large-scale BF.The paper highlights the unique advantages of large-scale BF and the practical performance of BFs in Baosteel,and explores the related parameter choice,comprehensively matched longevity technology optimization and tapping-stability improvement in terms of structure-design,longevity and equipments etc.The author stresses BF centered basic working regulation,hoping it can exert positive effect on the scientific development of large scale BF in China.展开更多
In this study, the blast performance of steel reinforced concrete(RC) beams was experimentally and analytically investigated. The experiment consists of a total of 10 one-half-scale beams subjected to different levels...In this study, the blast performance of steel reinforced concrete(RC) beams was experimentally and analytically investigated. The experiment consists of a total of 10 one-half-scale beams subjected to different levels of blast loading using live explosives. The reflected pressure-time histories were recorded and different damage levels and modes were observed. The blast resilience of the damaged beams was quantified by measuring the time-dependent displacements. Experiment results show that the damage in steel reinforced concrete beams with higher explosive mass is enhanced compared with that of the beams with smaller explosive mass at the same scaled distance. Based on the experiment data, an empirical expression is developed via dimensional analysis to correct the relationship between the midspan displacement and scaled distance. Besides, a complex single degree of freedom model(SDOF)incorporating complex features of the material behavior, high strain-rate effect and the column geometry was proposed and validated by test results.展开更多
This paper presents the design, test and analysis of a scaled cylindrical blast chamber. The blast chamber is a one-fifth dimensional size replica of the full-scale blast chamber(Emily). The blast chamber is semi-conf...This paper presents the design, test and analysis of a scaled cylindrical blast chamber. The blast chamber is a one-fifth dimensional size replica of the full-scale blast chamber(Emily). The blast chamber is semi-confined as one end is open. The scaled blast chamber is used to test concepts for closing the open end and allows the gas to vent at the same time. ANSYS AUTODYN calculated the pressure time histories for different closure scenarios. Comparing the results suggested a viable scenario, namely a structure consisting of a circular disc and a frame positioned at the open end of the blast chamber. The structure and cylindrical blast chamber were subjected to scaled blast tests and the pressure results are presented and discussed.展开更多
Dynamic Increase Factor (DIF) due to strain rate effect was examined with documented experimental work done by Razaqpur, et al. In the experiment work, two 1000 × 1000 × 70 mm reinforced concrete slabs were ...Dynamic Increase Factor (DIF) due to strain rate effect was examined with documented experimental work done by Razaqpur, et al. In the experiment work, two 1000 × 1000 × 70 mm reinforced concrete slabs were constructed. The slabs were subjected to blast loads generated by the detonation of either 22.4 kg or 33.4 kg of ANFO located at a 3.0 m standoff. Blast wave characteristics, including incident and reflected pressures and reflected impulses were measured. The slabs were modeled by explicit analysis with or without strain rate effect to study their behavior under blast load to compare their predicted and observed behavior. The predicted post-blast damage and mode of failure for each model is compared with the observed damage of experimental work. It was concluded that when the dynamic increase factor added to concrete and reinforcement materials due to strain rate effect, the behavior of model under blast load become closer to experimental work.展开更多
Implicit and explicit analyses were examined with experimental work done by Razaqpur et al. In the experiment work, two 1000 × 1000 × 70 mm reinforced concrete slabs were constructed. The slabs were subjecte...Implicit and explicit analyses were examined with experimental work done by Razaqpur et al. In the experiment work, two 1000 × 1000 × 70 mm reinforced concrete slabs were constructed. The slabs were subjected to blast loads generated by the detonation of either 22.4 kg or 33.4 kg of ANFO located at a 3.0 m standoff. Blast wave characteristics, including incident and reflected pressures and reflected impulses were measured. The slabs were modeled by implicit and explicit analysis to study their behavior under blast load to compare their predicted and observed behavior. The post-blast damage and mode of failure of each slab were observed. It was concluded that explicit analysis provides better modeling than implicit analysis.展开更多
文摘The blast-induced ground vibration prediction using scaled distance regression analysis is one of the most popular methods employed by engineers for many decades. It uses the maximum charge per delay and distance of monitoring as the major factors for predicting the peak particle velocity(PPV). It is established that the PPV is caused by the maximum charge per delay which varies with the distance of monitoring and site geology. While conducting a production blasting, the waves induced by blasting of different holes interfere destructively with each other, which may result in higher PPV than the predicted value with scaled distance regression analysis. This phenomenon of interference/superimposition of waves is not considered while using scaled distance regression analysis. In this paper, an attempt has been made to compare the predicted values of blast-induced ground vibration using multi-hole trial blasting with single-hole blasting in an opencast coal mine under the same geological condition. Further,the modified prediction equation for the multi-hole trial blasting was obtained using single-hole regression analysis. The error between predicted and actual values of multi-hole blast-induced ground vibration was found to be reduced by 8.5%.
文摘Large-scale BF is the tendency of domestic and foreign Iron-making technology.Due to the limit of resource,technology and equipment,we can not reach the planned goal after putting the big BF into production,it is of great significance to explore the key technologies again for the sound development of the large-scale BF.The paper highlights the unique advantages of large-scale BF and the practical performance of BFs in Baosteel,and explores the related parameter choice,comprehensively matched longevity technology optimization and tapping-stability improvement in terms of structure-design,longevity and equipments etc.The author stresses BF centered basic working regulation,hoping it can exert positive effect on the scientific development of large scale BF in China.
基金supported by The National Natural Science Foundation of China under Grant No.11390362 and No.11221202
文摘In this study, the blast performance of steel reinforced concrete(RC) beams was experimentally and analytically investigated. The experiment consists of a total of 10 one-half-scale beams subjected to different levels of blast loading using live explosives. The reflected pressure-time histories were recorded and different damage levels and modes were observed. The blast resilience of the damaged beams was quantified by measuring the time-dependent displacements. Experiment results show that the damage in steel reinforced concrete beams with higher explosive mass is enhanced compared with that of the beams with smaller explosive mass at the same scaled distance. Based on the experiment data, an empirical expression is developed via dimensional analysis to correct the relationship between the midspan displacement and scaled distance. Besides, a complex single degree of freedom model(SDOF)incorporating complex features of the material behavior, high strain-rate effect and the column geometry was proposed and validated by test results.
文摘This paper presents the design, test and analysis of a scaled cylindrical blast chamber. The blast chamber is a one-fifth dimensional size replica of the full-scale blast chamber(Emily). The blast chamber is semi-confined as one end is open. The scaled blast chamber is used to test concepts for closing the open end and allows the gas to vent at the same time. ANSYS AUTODYN calculated the pressure time histories for different closure scenarios. Comparing the results suggested a viable scenario, namely a structure consisting of a circular disc and a frame positioned at the open end of the blast chamber. The structure and cylindrical blast chamber were subjected to scaled blast tests and the pressure results are presented and discussed.
文摘Dynamic Increase Factor (DIF) due to strain rate effect was examined with documented experimental work done by Razaqpur, et al. In the experiment work, two 1000 × 1000 × 70 mm reinforced concrete slabs were constructed. The slabs were subjected to blast loads generated by the detonation of either 22.4 kg or 33.4 kg of ANFO located at a 3.0 m standoff. Blast wave characteristics, including incident and reflected pressures and reflected impulses were measured. The slabs were modeled by explicit analysis with or without strain rate effect to study their behavior under blast load to compare their predicted and observed behavior. The predicted post-blast damage and mode of failure for each model is compared with the observed damage of experimental work. It was concluded that when the dynamic increase factor added to concrete and reinforcement materials due to strain rate effect, the behavior of model under blast load become closer to experimental work.
文摘Implicit and explicit analyses were examined with experimental work done by Razaqpur et al. In the experiment work, two 1000 × 1000 × 70 mm reinforced concrete slabs were constructed. The slabs were subjected to blast loads generated by the detonation of either 22.4 kg or 33.4 kg of ANFO located at a 3.0 m standoff. Blast wave characteristics, including incident and reflected pressures and reflected impulses were measured. The slabs were modeled by implicit and explicit analysis to study their behavior under blast load to compare their predicted and observed behavior. The post-blast damage and mode of failure of each slab were observed. It was concluded that explicit analysis provides better modeling than implicit analysis.
