scholarly journals Statistical Characterization of Damage of Different Surface P-Wave Velocity Sets under Dynamic Load and Study on Overall Radon Detection Consistency

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Shuai Zhang ◽  
Jiantao Cao ◽  
Yong Liu ◽  
Jun Liu ◽  
Changshou Hong ◽  
...  

Abstract On the basis of reviewing the existing research status of cumulative damage of the rock mass and summarizing the existing engineering application fields of radon, this paper attempts to apply radon detection technology to the research field of rock damage mechanics so as to monitor the evolution process of cumulative damage of the rock mass. Based on the above research purposes, a test device for detecting cumulative damage of radioactive rocks by surface radon gas was designed, and the test results were obtained by integrating the system to implement the test scheme. Due to the limitation of the nonmetallic ultrasonic detector, a single blasting damage value of 25 detection points appears after a single blasting measurement, which is a surface longitudinal wave velocity characterization damage set, while the surface radon exhalation rate in the subsequent analysis process is an overall characterization value; that is, the existence of damage directly affects the whole body radon exhalation rate of the test block, and the data dimensions of the two are different. In order to solve this problem, we try to introduce three data evaluation methods, the average weighting method, grey prediction method, and K-means clustering algorithm, and compare the feasibility of these three methods. It is proved that there is a certain linear relationship between the radon exhalation rate and the cumulative damage, which further verifies the feasibility of using radon to detect cumulative damage. The results show that the cumulative damage of loaded radioactive rock test blocks can be reflected by surface radon detection technology, and finally, the correlation between the cumulative damage characteristics and the continuous change of the body radon exhalation rate is obtained. Based on the correlation, the body radon exhalation rate is introduced into the field of fractured rock mass damage characterization, which is mutually improved with common monitoring methods such as acoustic emission and microseismic monitoring, supplementing and enriching the means of rock mass damage evolution characterization, providing a theoretical basis for finely describing the whole process of fracture closure and initiation, and finally accurately ensuring the stability of surrounding rock under the action of deep underground engineering excavation disturbance.

2015 ◽  
Vol 713-715 ◽  
pp. 304-313
Author(s):  
Shu Guang Wang ◽  
Wei Yang ◽  
Qing Chen ◽  
Jian Hua Chen ◽  
Cong Han

The regularity of radon exhalation rate in the over-broken granite tunnel is susceptible to weather conditions and ventilation styles. Based on the calculation model of radon exhalation in tunnel, some experiments have been carried out to analyze the variations of radon exhalation in cases of natural ventilation, blowing ventilation and exhaust ventilation separately. The results show that there is a linear relation between the radon exhalation and the natural ventilation quantity, and also between the radon exhalation and the ambient temperature; the radon exhalation in the case of exhaust ventilation is 63% higher than that in the blowing case under the condition of the same ventilation quantity and ambient temperature. Therefore, it is suggested that operation in the tunnel in high temperature be avoided in summer, and the blowing ventilation be adopted as an effective way for ventilation.


Nukleonika ◽  
2016 ◽  
Vol 61 (3) ◽  
pp. 281-288 ◽  
Author(s):  
Karol Holý ◽  
Monika Műllerová ◽  
Martin Bulko ◽  
Oľga Holá ◽  
Terézia Melicherová

Abstract Radon activity concentration (RAC) in the outdoor atmosphere was monitored in four localities of Slovakia. The distance between the localities were up to 130 km. The localities had a diverse orography, ranging from flatland to hilly terrain. A significant influence of orography and 226Ra and 222Rn content in soil on diurnal time series of RAC was found. A simple approach of determining radon exhalation rate from soil based on the increase of RAC from daily minima to maxima and removal characteristic of radon is presented. A linear dependency between radon exhalation rate from the soil and RAC in the soil gas at a depth of 0.8 m was found for sandy soils.


2018 ◽  
Vol 10 (9) ◽  
pp. 3005
Author(s):  
Ling-feng Xie ◽  
Shu-liang Zou ◽  
Xiang-yang Li ◽  
Chang-shou Hong ◽  
Hong Wang ◽  
...  

Radon is internationally recognized as one of the seven seismic precursors. A self-assembly ultrasonic generator and experimental apparatus for radon measurement were utilized to explore the radon exhalation regularities of water-bearing porous media under different ultrasonic intensities. The experimental results showed that there was a coupling relationship among radon exhalation rate, moisture content, and ultrasonic frequency. With the increase of the frequency of the ultrasonic wave, its effect on the promotion of radon exhalation rate was found to be a more obviously positive linear correlation. The radon exhalation rate, which could climb to a maximum value of 0.179 Bq·m−2·s−1 in a naturally air-dried sample, increased at first and then decreased along with increased moisture content. Moreover, this study found that the ultrasonic wave had the most remarkable promoting effects on the radon exhalation rate of porous media with high moisture content, and there is a positive linear correlation between the growth rate of the radon exhalation rate and moisture content. The experimental results could provide a beneficial reference for the continual monitoring of radon in a seismically active belt and an explanation of radon anomalies; however, the proposed experimental model was simplified, so further insights are strictly required for a reliable correlation with the real monitoring of radon in a seismically active belt.


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