scholarly journals Study on hydraulic-controlled blasting technology for pressure relief and permeability improvement in a deep hole

2017 ◽  
Vol 159 ◽  
pp. 433-442 ◽  
Author(s):  
Qing Ye ◽  
ZhenZhen Jia ◽  
Chunshan Zheng
Keyword(s):  
Deep Hole ◽  
Pressure Relief

scholarly journals Optimization and Practice for Partition Pressure Relief of Deep Mining Roadway Using Empty-Hole and Deep-Hole Blasting to Weaken Coal

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Baobao Chen ◽  
Changyou Liu ◽  
Fengfeng Wu
Keyword(s):  
Large Diameter ◽  
Elevation Angle ◽  
Failure Behavior ◽  
Deep Hole ◽  
Pressure Relief ◽  
Deep Mining ◽  
Safe Level ◽  
Drilling Parameters ◽  
Decoupling Coefficient ◽  
Stress Boundary

Rockbursts are among the most harmful dynamic disasters, threatening the personnel safety and mine operation. In order to alleviate stress concentration of roadsides and prevent rockbursts, the large-diameter boreholes and deep-hole blasting are employed for partition pressure relief in the deep mining roadway. Combined with failure behavior and stress distribution of the coal, the multilevel division of risk degree for roadsides stress is determined. Based on the orthogonal test of borehole pressure relief in the general danger partition, the response degree of quantitative indexes to main factors influencing the pressure relief effect is considered. The optimal drilling parameters of 120.0 mm diameter, 20.0 m depth, 1.0 m hole spacing, and 5° elevation angle are obtained, determining the stress boundary of safe pressure relief with boreholes. At higher dangerous stress divisions, the optimized blasting parameters through numerical simulation could be obtained as follows: 15.0 m depth, 1.3 decoupling coefficient, and 2.0 m hole spacing, and meanwhile, a stress relief partition of crisscross cracks with 0.61 m height is formed. The roadsides stress could be well controlled within the safe level. Then, an optimal combination of pressure relief is applied to different stress partition of roadsides, and the effectiveness is validated by field test, which proves remarkably applicable for engineering.

scholarly journals Application of Presplitting Blasting Technology in Surrounding Rock Control of Gob-Side Entry Retaining with Hard Roof: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Shuang Gong ◽  
Yi Tan ◽  
Yunpeng Liu ◽  
Dan Zhu ◽  
Yang Yu
Keyword(s):  
Crack Formation ◽  
Formation Rate ◽  
Industrial Test ◽  
Surrounding Rock ◽  
Control Measures ◽  
Deep Hole ◽  
Pressure Relief ◽  
Factors Affecting ◽  
Hard Roof ◽  
Implementation Effect

Through the analysis of the mining situation and geological data of Qidong mine and working face, the key factors affecting the roof cutting and pressure relief roadway retention along the goaf are defined. Combined with numerical simulation and field test, the reasonable parameters of combined presplitting blasting of deep hole and shallow hole in hard roof are determined, and the roof cutting effect is tested through field observation and borehole peeping. The comprehensive control measures for the surrounding rock of 7135 roadway with roof cutting and pressure relief and gob retaining are formulated, including safety assurance technical measures, such as advanced precrack and seam cutting, roof reinforcement and support, gangue retaining protection beside the roadway, lagging temporary support, and on-site industrial test monitoring scheme. Aiming at the hard rock roof, the “deep hole + shallow hole” presplitting blasting roof cutting technology is developed, and the economic and reasonable blasting parameters are determined. The drilling peep results show that the implementation effect of presplitting blasting technology is good. The results showed that deep holes and shallow holes with small spacing and parallel to each other shall be arranged on the planned seam line. The peeping results show that the crack formation rate in the charging section exceeds 85% in the process of deep hole blasting. In shallow hole blasting, the crack formation rate of charging section is more than 90%.

On the assessment of ventricular reconfiguration after intracranial pressure relief. What information is encoded in size and form?

2004 ◽  
Vol 31 (S 1) ◽  
Author(s):  
C Preul ◽  
M Tittgemeyer ◽  
D Lindner ◽  
C Trantakis ◽  
J Meixensberger ◽  
...  
Keyword(s):  
Intracranial Pressure ◽  
Pressure Relief

Revisão sistemática sobre os posicionamentos de tilt e recline para usuários de cadeira de rodas

2018 ◽  
Vol 19 (3) ◽  
pp. 417
Author(s):  
Luma Carolina Gradim ◽  
Paulo Vinícius Braga Mendes ◽  
Debora Caires Paulisso ◽  
Daniel Marinho Cezar Da Cruz
Keyword(s):  
Web Of Science ◽  
Pressure Relief

Introdução: O uso prolongado de cadeira de rodas pode acarretar em lesões por pressão, dores e perda de independência funcional. O método de inclinação e/ou de reclinar (tilt/recline) é prescrito para neutralizar e minimizar esses efeitos nocivos. Porém, não há um consenso de qual ângulo destes recursos é o ideal, bem como a eficiência destes para os usuários. Objetivos: a) conhecer e verificar quais angulações dos sistemas de posicionamento de tilt e recline são mais utilizadas e favoráveis para os usuários de cadeira de rodas e; b) classificar pesquisas encontradas pelo seu nível de evidência. Métodos: Trata-se de uma revisão sistemática sem meta-análise. Foram recuperados artigos publicados até setembro de 2017, na Biblioteca Virtual em Saúde-BVS, Pubmed, Scopus, Web of Science e OTseeker, utilizando as palavras-chave: “wheelchair”, “tilt-in-space”, “tilt-recline”, “recline”, “pressure relief” e “repositioning systems”. Resultados: A maioria dos artigos selecionados correspondeu ao nível IV de evidência, que se caracteriza como estudos não experimentais. Os principais resultados apontam que a combinação de tilt e recline favorece o alívio de pressão na região das nádegas dos usuários de cadeira de rodas e promove conforto postural, mas para existir eficácia, há a necessidade de maiores angulações. Identificou-se que os menores ângulos são os mais realizados pelos usuários de cadeira de rodas, com a finalidade de gerar conforto e alívio de pressão. Conclusão: A prescrição e utilização dos sistemas de posicionamentos variáveis favorecem o usuário de cadeira de rodas, sendo os efeitos proporcionalmente relacionados ao grau de angulação adotado.Palavras-chave: úlcera por pressão, reabilitação, traumatismos da medula espinal, cadeiras de rodas.

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