scholarly journals The Prevention and Control Mechanism of Rockburst Hazards and Its Application in the Construction of a Deeply Buried Tunnel

2019 ◽  
Vol 9 (17) ◽  
pp. 3629 ◽  
Author(s):  
Heng Zhang ◽  
Yimo Zhu ◽  
Liang Chen ◽  
Weidong Hu ◽  
Shougen Chen
Keyword(s):  
Prevention And Control ◽  
High Stress ◽  
Field Application ◽  
Underground Engineering ◽  
Global Challenge ◽  
High Geostress ◽  
Jinping Ii Hydropower Station ◽  
Active Release ◽  
Water Swelling ◽  
And Control

Rockburst hazards induced by high geostress are particularly prominent during the construction of underground engineering. Prevention and control of rockburst is still a global challenge in the field of geotechnical engineering, which is of great significance. Based on the tunnel group of the Jinping II hydropower station of China, this paper analyzed the mechanical principle of support in the process of construction, and discussed in detail the active release and passive support by numerical simulation and field application. The results show that as two active measures, stress relieve holes and advanced stress relief blasting can release the energy of the microseismic source and transfer the high stress to the deeper surrounding rock, make the surface rock wall with a relatively low stress act as a protective barrier. Their stress release rate is about 12% and 33% in this project, respectively. In term of passive measure, the combined rapid support, which is mainly composed of water swelling anchor and nano-admixture shotcrete, is also an effective way to prevent and control the rockburst under high geostress.

scholarly journals Techniques for Progressive Failure Simulation of Hard Brittle Surrounding Rockmass: Taking the URL Test Tunnel as an Example

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Daning Zhong ◽  
Jianlin Chen ◽  
Hui Zhou ◽  
Xiangrong Chen ◽  
Yali Jiang ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Progressive Failure ◽  
Failure Process ◽  
High Stress ◽  
Constitutive Models ◽  
Discrete Element ◽  
Discontinuous Deformation Analysis ◽  
Deformation Analysis ◽  
Underground Engineering ◽  
And Control

Accurate simulation of the failure process of hard brittle surrounding rockmass is very important for the analysis and control of the structural stability in deep underground engineering. In order to simulate the progressive failure process of the hard brittle surrounding rockmass, a continuous discontinuous deformation analysis method that couples the finite element and discrete element is adopted. Taking the URL test tunnel in Canada as an engineering case, the constitutive model of the contact considering the effects of cohesion weakening and friction strengthening is applied, and the 2D approximation to 3D excavation by applying elastic modulus reduction technology is adopted to simulate the range and depth of crack growth of the surrounding rockmass. Then, the comparison between simulated results and on-site monitoring results is performed, which shows good consistency. At the same time, the key factors in the numerical simulation of progressive failure in hard brittle rockmass are identified, including the number of elements, excavation effects, and constitutive models. The results show that the constitutive model determines the basic form of crack propagation, but in order to accurately simulate the progressive propagation of cracks, the number of elements must be sufficient enough and the effects of 3D excavation must be considered. The analysis accurately simulates the progressive failure characteristics of hard brittle surrounding rockmass under high stress, achieving the purpose of reasonably grasping the degree of damage to the surrounding rockmass, and provides technical reference and support on how to accurately simulate the failure of hard brittle surrounding rockmass using the finite discrete element method.

scholarly journals Mechanism of Coal Burst and Prevention Practice in Deep Asymmetric Isolated Coal Pillar: A Case Study from YaoQiao Coal Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Chengchun Xue ◽  
Anye Cao ◽  
Wenhao Guo ◽  
Songwei Wang ◽  
Yaoqi Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Mine ◽  
Prevention And Control ◽  
High Stress ◽  
Coal Pillar ◽  
Support Pressure ◽  
Mining District ◽  
Coal Pillars ◽  
And Control ◽  
The Impact

Coal pillar bursts continue to be a severe dynamic hazard. Understanding its mechanism is of paramount importance and crucial in preventing and controlling its occurrence. The extreme roadway deformations from the asymmetric isolated coal pillars in the central mining district of YaoQiao Coal Mine have responded with frequent intense tremors, with risky isolated coal pillar bursts. The theoretical analysis, numerical simulation, and field measurements were done to research the impact of spatial overburden structure and stress distribution characteristics on the isolated coal pillar area, aiming to reveal the mechanism of coal pillar burst leading to the practice of prevention and control in the asymmetric isolated coal pillar area. The study shows that the overburden structure of the asymmetric is an asymmetric “T” structure in the strike-profile, and the stress in the coal pillar is mostly asymmetric “saddle-shaped” distribution, with the peak stress in the east side of the coal pillar, and the coal pillar is a “high stress serrated isolated coal pillar.” Numerical simulation results showed that the support pressure in the isolated coal pillar area on the strike profile was asymmetrically “saddle-shaped” distribution. The peak vertical stress in the coal pillar area continued to rise and gradually shifted to the mining district's deep part. As a result, the response of the roadway sides to the dynamic load disturbance was more pronounced. They developed a coal burst prevention and control program of deep-hole blasting in the roof of asymmetrical isolated coal pillar roof and unloading pressure from coal seam borehole. Monitored data confirmed that the stress concentration was influential in the roadway’s surrounding rock in the asymmetric isolated coal pillar area, circumventing coal pillar burst accidents. The research outcomes reference the prevention and control of coal bursts at isolated working faces of coal pillars under similar conditions.

scholarly journals Current efforts towards safe and effective live attenuated vaccines against African swine fever: challenges and prospects

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Tao Wang ◽  
Rui Luo ◽  
Yuan Sun ◽  
Hua-Ji Qiu
Keyword(s):  
Prevention And Control ◽  
African Swine Fever Virus ◽  
African Swine Fever ◽  
Field Application ◽  
Stable Cell Line ◽  
Effective Vaccine ◽  
Hemorrhagic Disease ◽  
Wide Field ◽  
Live Attenuated Vaccines ◽  
And Control

Abstract Background African swine fever (ASF) is a fatal hemorrhagic disease in domestic pigs and wild boar caused by African swine fever virus (ASFV). Since ASF has been introduced into Europe and Asia, the major pig-raising areas, posing a huge threat to the pork industry worldwide. Currently, prevention and control of ASF are basically dependent on strict biosecurity measures and stamping-out policy once ASF occurs. Main text The major risks of ASF spread are insufficient biosecurity measures and human behaviors. Therefore, a safe and effective vaccine seems to be a reasonable demand for the prevention and control of ASF. Due to the efficacy advantage over other types of vaccines, live attenuated vaccines (LAVs), especially virulence-associated genes deleted vaccines, are likely to be put into emergency and conditional use in restricted areas if ASF is out of control in a country with a huge pig population and pork consumption, like China. However, the safety, efficacy, and genetic stability of current candidate ASF LAVs require comprehensive clinical evaluations prior to country-wide field application. Several critical issues need to be addressed to commercialize an ideal ASF LAV, including a stable cell line for manufacturing vaccines, differentiation of infected from vaccinated animals (DIVA), and cross-protection from different genotypes. Conclusion A safe and effective DIVA vaccine and an accompanying diagnostic assay will facilitate the prevention, control, and eradication of ASF, which is quite challenging in the near future. Graphical Abstract

scholarly journals International leadership for the control of disease outbreaks relating to “One Health”

2018 ◽  
Vol 32 (2) ◽  
pp. 106-110
Author(s):  
Samlee Plianbangchang
Keyword(s):  
Leadership Development ◽  
Cultural Context ◽  
Prevention And Control ◽  
Design Methodology ◽  
One Health ◽  
Disease Outbreaks ◽  
Content Type ◽  
Global Challenge ◽  
Areas Of Concern ◽  
And Control

Purpose In view of the current global challenge of infectious diseases transmitted from animal to man, this is a complimentary piece of paper to promote, in particular, the inter-sectorial and multi-disciplinary coordination and cooperation in their prevention and control, among all concerned agencies/organizations at both policy and operational levels, with special emphasis on the importance of leadership development within the socio-cultural context of health, and with particular reference to the concept of “One Health” that implies the intimate interaction between man and animal within their own environments/ecosystems. The paper aims to discuss these issues. Design/methodology/approach This is a commentary piece. Findings The paper directly and indirectly suggests lacunae in several areas of concern for further research and development to fill the knowledge gap in such a prevention and control. Originality/value This is a commentary piece.

Linking decision-making research and cancer prevention and control: Important themes.

2005 ◽  
Vol 24 (4, Suppl) ◽  
pp. S106-S110 ◽  
Author(s):  
Kevin D. McCaul ◽  
Ellen Peters ◽  
Wendy Nelson ◽  
Michael Stefanek
Keyword(s):  
Decision Making ◽  
Cancer Prevention ◽  
Prevention And Control ◽  
Cancer Prevention And Control ◽  
And Control
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