Airflow-Dust Migration Law and Control Technology Under the Simultaneous Operations of Shotcreting and Drilling in Roadways

Chen, Lianjun; Liu, Guoming

doi:10.1007/s13369-018-3673-5

Cited by 59 publications

(19 citation statements)

References 18 publications

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“…Bolts are vital to the advancement of underground excavation in engineering work, such as subway tunnels and coal mines, as they connect broken rock mass, enhance the stability of underground coal mine roadways and surrounding rock, and reduce the occurrence of rock burst . In countries such as China where huge amount of coal is mined, problems of roof falling (roof collapse), land subsidence, and collapse result in a series of secondary disasters, directly threatening production, and life safety . Monitoring and evaluation of the anchoring performance is an important basis to judge the effectiveness of bolts, and hence, to ascertain the safety of the underground coal mine roadways.…”

Section: Introductionmentioning

confidence: 99%

Monitoring and correction of the stress in an anchor bolt based on Pulse Pre‐Pumped Brillouin Optical Time Domain Analysis

Liu

Chai

Chen

et al. 2020

Energy Science & Engineering

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Bolt is an important connection in underground construction and monitoring its stress characteristics is essential to evaluate the effectiveness of bolt. The strain information collected along a rock bolt reveals the long-term movement characteristics of rock mass, which greatly helps toward disaster prevention and risk warning.Grooving on the surface of a bolt and embedding an optical fiber is one of the main methods for monitoring the anchorage performance and stress distribution around the bolt in underground engineering. In this study, Pulse Pre-Pumped Brillouin Optical Time Domain Analysis (PPP-BOTDA) technology is used to evaluate the stress, axial force, and shear stress distribution of the bolt under tensile load for different types (grooved and nongrooved) of bolts embedded in concrete with resin as anchoring agent. The results show that the PPP-BOTDA sensor can be used to monitor the stress state of the bolt embedded in concrete with resin as anchoring agent when the bolt is subjected to a tensile force. However, the apparent stress value measured in this way is not the actual stress value of the bolt, but is an increased value caused due to the groove. The closer to the exposed end of the bolt, the greater is the deviation between the apparent stress value and the actual stress value of the bolt. Based on the monitoring results from this experimental study, a stress reduction calculation method is proposed, which can change the measured value into the actual stress of the bolt. K E Y W O R D Saxial force, bolt, PPP-BOTDA technology, pullout test, shear stress 2012 |

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Section: Introductionmentioning

confidence: 99%

Monitoring and correction of the stress in an anchor bolt based on Pulse Pre‐Pumped Brillouin Optical Time Domain Analysis

Liu

Chai

Chen

et al. 2020

Energy Science & Engineering

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“…During the accelerated pressure drop experiment, the conveying of concrete particles was accelerated at a specific speed from one point and finally reached the movement trend at a constant speed [30][31][32]. e momentum equation was used to calculate the pressure drop during this process:…”

Section: Resultsmentioning

confidence: 99%

“…Pressure drop should be considered in the design of a concrete conveying system. When calculating the pressure drop in delivery lines, the classic phase diagram is often applied, in which the pressure drop in unit length of the line is expressed as a function related to speed [4,5]. Forces in concrete and on the pipe walls predict the pressure drop in the conveying of concrete.…”

Section: Introductionmentioning

confidence: 99%

Research on Pressure Drop in the Accelerate Zone of Horizontal Conveying of Concrete Spraying

Gong

et al. 2019

Advances in Civil Engineering

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A pressure transmitter was installed at a specific position in a concrete conveying line to disclose the pressure drop when compressed air was conveyed during concrete spraying. A statistical analysis of the pressure at different positions was undertaken. Experimental results demonstrated that in the accelerate zone of horizontal conveying of concrete in the line, the pressure drop mainly occurred during the acceleration, collision, and friction processes. The momentum equation was introduced during the experiment, which interpreted the pressure drop caused by the accelerated conveying of concrete. The theoretical equation was corrected based on the results of theoretical experiments by introducing the value of α, and the experimental results were then optimized, thus obtaining an approximate model of pressure drop during the conveying of concrete. In addition, experimental results were compared with a model equation that showed the reliability of the proposed model. Research conclusions are of great significance to regulate the pressure drop in the conveying line of concretes, to design working parameters of concrete spraying devices, and to predict the ultimate distance for the conveying of concrete.

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“…By the end of 2015, the dust phthisis is still serious in reported occupational diseases [14]. As for a tunnel or mine roadway in China, the number of people exposed to dust is the largest in the world and the condition of dust in the process of anchoring and shotcreting is the worst, as is shown in Figure 1 [15,16]. erefore, it is urgent to weed out the traditional drymix shotcrete technology and develop the technology of dust suppression.…”

Section: Introductionmentioning

confidence: 99%

Research on Dust Suppression Technology of Shotcrete Based on New Spray Equipment and Process Optimization

Zhou

Chen

et al. 2019

Advances in Civil Engineering

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In order to reduce the dust hazard of shotcrete, the paper analyzed the mechanism of dust production from the perspective of various dust sources and developed the plunger-type wet spraying machinery and wet mixer which can be applied in the small-section tunnel for reducing dust on the root cause. The dust concentration between dry-mix shotcrete and wet-mix shotcrete was compared and analyzed. The results showed that the average total dust concentration and respirable dust concentration in the process of dry spraying were 99.4 mg/m3 and 52 mg/m3, respectively, while 9.8 mg/m3 and 4.08 mg/m3 in the wet-mix shotcrete process, and the average dust concentration decreased by more than 90% after applying new wet-mix shotcrete outfits. The clean zone of dust was divided according to the dust distribution. Finally, the dust suppression technology was optimized by using an accelerator and adjusting wind pressure and spraying angle. Results indicated that the application of the accelerator reduced the dust production efficiently; moreover, when the wind pressure was 0.2 MPa with 1 m spraying distance and 90° angle of spraying, the dust concentration and rebound reached the minimum.

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Airflow-Dust Migration Law and Control Technology Under the Simultaneous Operations of Shotcreting and Drilling in Roadways

Cited by 59 publications

References 18 publications

Monitoring and correction of the stress in an anchor bolt based on Pulse Pre‐Pumped Brillouin Optical Time Domain Analysis

Monitoring and correction of the stress in an anchor bolt based on Pulse Pre‐Pumped Brillouin Optical Time Domain Analysis

Research on Pressure Drop in the Accelerate Zone of Horizontal Conveying of Concrete Spraying

Research on Dust Suppression Technology of Shotcrete Based on New Spray Equipment and Process Optimization

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