Frequency channeling: a concept to increase the frequency and control the PPV of blast-induced ground vibration waves in multi-hole blast in a surface mine

Author(s):  
Chitranjan Prasad Singh ◽  
Hemant Agrawal ◽  
Arvind Kumar Mishra
2019 ◽  
Vol 56 (7) ◽  
pp. 929-941 ◽  
Author(s):  
Jhon Silva-Castro

Ground vibration prediction and control from mine blasting is a complex task involving disciplines such as geotechnical engineering, explosives engineering, and geology. Despite the importance of controlling ground vibrations, the mining industry commonly uses empirical methodologies based on concepts related to the nuclear tests era (charge weight scaling relationships). Over the past decade, attempts have been made to popularize more elaborate methodologies. These methods range from basic waveform superposition to analytical and numerical methods. Such methodologies are difficult to utilize daily because of their complexity, sometimes low accuracy (despite their sophistication), requirement for difficult to obtain parameters, and time needed to reach solutions using complex algorithms. In this paper, a different methodology to control and predict ground vibrations from blasting is presented. This methodology uses a semi-empirical approach, where the generation and propagation of ground vibration waves and the ground vibration characteristics at a point of interest are considered through the collection of a signature waveform. The methodology allows assessment of the optimum delay between charges to minimize and control ground vibration levels. A case study is included to demonstrate the benefits and the methodology in detail.


2012 ◽  
Vol 170-173 ◽  
pp. 1414-1418 ◽  
Author(s):  
Dong Tao Li ◽  
Jing Long Yan ◽  
Le Zhang

Beijing East Road No.1 tunnel in Guiyang city has the most complexity in arround, so prediction and control the blasting vibration is the most important task. In order to improve the accuracy of the prediction of the blasting vibration to mitigate the possible hazard in tunnel construction, studied on method of predicting peak particle velocity (PPV) using support vector machine (SVM) and established regression prediction model based on SVM. Comparisons between the predicted PPV using the empirical equation regression and SVM was made, find that the SVM gives much better prediction of PPV than does the empirical equation regression.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yingguo Hu ◽  
Zhaowei Yang ◽  
Erlei Yao ◽  
Meishan Liu ◽  
Yu Rao

This paper focuses on the investigation and control of the blasting-induced ground vibration under cold condition. The mechanical performance and wave propagation characteristics of the frozen rock mass are quite different from that of the conventional condition. Laboratory tests were implemented to investigate the wave impedance of rock mass in the frozen, saturated, normal, and drying states. Results reveal the longitudinal wave velocity could be enlarged by 40 percent in the frozen state. Then long-term monitoring of blasting vibration was implemented based on the blasting excavation of the Fengman hydropower station reconstruction project in the north of China. Results demonstrate the PPV and frequency both attenuate much slower when the rock mass is frozen, and the obvious turning points of PPV could be found between different temperatures, where the change of the PPV relationship happens. At last, numerical simulation of the blasting seismic wave attenuation and the response in the protected structure was implemented. The equivalent freezing simulation method was proposed and verified with the site experiment data. Results demonstrate that the attenuation coefficient decreases obviously as the frozen depth of the rock mass increases. The dynamic degree response in structure is much stronger and the maximum charge weight per delay was limited more strictly under the frozen condition. A most adverse frozen depth was determined when the charge weight per delay gets the minimum value. With the above control approaches, a total of 676 blasting was completed in Fengman hydropower station reconstruction and no case of excessive measurement could be found.


Author(s):  
R. R. Dils ◽  
P. S. Follansbee

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.


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