scholarly journals Analysis of Stability Factors of Roadway Roof and Determination of Unsupported Roof Distance

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Sen Yang ◽  
Xinzhu Hua ◽  
Xiao Liu ◽  
Chen Li

To determine the impact of influencing factors on unsupported roof stability in coal mine roadway, a mechanical model of the unsupported roof was built. FLAC 3D numerical simulation was utilized to study the stability of the unsupported roof under the influence of the depth of the roadway, the thickness of the roof, and the unsupported-support distance. In view of the key influencing factors, the geological conditions of the site, and the relationship between the tensile stress and tensile strength of the unsupported roof, the maximum unsupported roof distance during roadway excavation was determined. Considering the surplus safety factor of the unsupported roof, the reasonable unsupported roof distance during the excavation of roadway 150802 was finally determined to be 2.08 m. The comprehensive roadway excavation speed increased by 62.7%, achieving a monthly progress over 500 m.

2020 ◽  
Vol 2 (7) ◽  
pp. 91-99
Author(s):  
E. V. KOSTYRIN ◽  
◽  
M. S. SINODSKAYA ◽  

The article analyzes the impact of certain factors on the volume of investments in the environment. Regression equations describing the relationship between the volume of investment in the environment and each of the influencing factors are constructed, the coefficients of the Pearson pair correlation between the dependent variable and the influencing factors, as well as pairwise between the influencing factors, are calculated. The average approximation error for each regression equation is determined. A correlation matrix is constructed and a conclusion is made. The developed econometric model is implemented in the program of separate collection of municipal solid waste (MSW) in Moscow. The efficiency of the model of investment management in the environment is evaluated on the example of the growth of planned investments in the activities of companies specializing in the export and processing of solid waste.


2015 ◽  
Vol 60 (11) ◽  
pp. 1-15
Author(s):  
Olga Leszczyńska-Luberek

The author presents the importance of the new European System of National and Regional Accounts (ESA 2010) for statistics of the general government sector. She pays particular attention to the development of data for the excessive deficit procedure. The article explains the methodological changes made to the studies in this field parallel to the ESA 2010. It discusses, among others, issues related to defining the deficit and debt of the general government, as well as the determination of a new way registering transfer of liabilities of pension schemes. It also presents the impact of new methodological guidelines for the relationship of deficit and debt to GDP in the Member States of the European Union.


2013 ◽  
Vol 2 (1) ◽  
pp. 19
Author(s):  
Said JAOUADI ◽  
Lamia ARFAOUI ◽  
Azza ZIEDI

The paper attempted to examine the causal relationship between political instability and growth. Currently, the world continues to record huge number of popular revolutions in the region MENA, to improve the social environment and to consolidate implementing an effective governance. Although, the uprising has harmed the financial and economic situation in these countries, and became a threat for the stability of the countries, in overall.The manuscript accounts for the impact of political instability on the growth of the developing countries, in the shadow of the widespread of the revolutions since 2011. The paper attempted to illuminate the reality of the relationship between political environment and growth through the estimation of panel, comprising 69 developing countries 1985-2012.In the current paper, the authors conducted an empirical investigation, in which we bore out the claims raised in many surveys and the conclusions drawn by several authors about the harmful impact of political instability on the fundamental bases of the economy, in countries recording political instability.


BMJ Open ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. e028553 ◽  
Author(s):  
Florian Schederecker ◽  
Christoph Kurz ◽  
Jon Fairburn ◽  
Werner Maier

ObjectivesThis study aimed to assess the impact of using different weighting procedures for the German Index of Multiple Deprivation (GIMD) investigating their link to mortality rates.Design and settingIn addition to the original (normative) weighting of the GIMD domains, four alternative weighting approaches were applied: equal weighting, linear regression, maximization algorithm and factor analysis. Correlation analyses to quantify the association between the differently weighted GIMD versions and mortality based on district-level official data from Germany in 2010 were applied (n=412 districts).Outcome measuresTotal mortality (all age groups) and premature mortality (<65 years).ResultsAll correlations of the GIMD versions with both total and premature mortality were highly significant (p<0.001). The comparison of these associations using Williams’s t-test for paired correlations showed significant differences, which proved to be small in respect to absolute values of Spearman’s rho (total mortality: between 0.535 and 0.615; premature mortality: between 0.699 and 0.832).ConclusionsThe association between area deprivation and mortality proved to be stable, regardless of different weighting of the GIMD domains. The theory-based weighting of the GIMD should be maintained, due to the stability of the GIMD scores and the relationship to mortality.


1996 ◽  
Vol 04 (01) ◽  
pp. 1-17 ◽  
Author(s):  
LARS KOLVEREID ◽  
ERLEND BULLVAG

Acknowledgements: We would like to thank the Norwegian Royal Ministry of Industry and the Bodø Graduate School of Business for the financial support that made this research possible. We would also like to thank the Society of Associated Researchers in Entrepreneurship under whose auspices the data for this study was collected. An earlier version of this paper was presented at the 3rd Annual Global Entrepreneurship Conference, Lyon, France, March 1993. The present research investigated: (1) the relationship between entrepreneurs’ growth intentions and actual firm growth, (2) the stability of growth intentions, and (3) the relationship between changes in intentions and actual firm growth. Using a longitudinal design, data were collected from Norwegian entrepreneurs for 1990 and 1992. The results indicate that growth intentions may be used to predict actual growth, that past intentions are related to later intentions, and that changes in growth intentions are associated with changes in growth patterns.


2018 ◽  
Vol 227 (2) ◽  
pp. 307-316
Author(s):  
Lect. Intisar Sukkar Khioun

     The relationship between man and climate is of great importance in climate studies, as climate is the most natural climatic element in the sense of comfort or distress of man, and humans can live comfortably if the degree of heat between (17-31 m) and the human feeling of heat and cold and then rest or discomfort not only caused by the air temperature but depends on many elements including solar radiation, air movement, relative humidity, the level of human activity and the type of clothing worn, and the presumption has used Biophysiological temperature and Cooling guide in this study to demonstrate the impact of climate on human comfort in the city of Rutba and relying on the climatic data for thirty years.


2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Quang Huy Nguyen

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working.


2017 ◽  
pp. 81-85
Author(s):  
G. L. IGNATOVA ◽  
V. N. ANTONOV

The article discusses the problem of COPD combined with CAD, determination of inflammatory markers and the prognostic BODE, DOSE and ADO indices. The aim of the study was to evaluate the effect of PCV13 immunization on clinical and functional manifestations of systemic inflammation in patients with COPD and CAD, as well as the relationship with the prognostic markers. Material and methods: The study included 36 male patients with COPD and 36 patients with COPD and CAD, FC II-III stable angina who were treated at Regional Clinical Hospital _4 in Chelyabinsk during the period 2015--2016. Conclusions: 1. Patients with COPD combined with CAD had statistically significant clinical and functional disorders manifested by an increase in the degree of dyspnea and reduction in FEV1. 2. In patients with COPD concomitant with CAD, against the background of the comorbidities, the levels of systemic inflammation markers — C-reactive protein, fibrinogen and procalcitonin — were more overt than in patients only with COPD. 3. Monitoring changes in procalcitonin levels could be used as an additional highly informative method for estimating the probability of the presence of bacterial inflammation and effectiveness of therapy. 4. The prognostic BODE, DOSE and ADO indices tend to decrease unidirectionally under the impact of vaccination with pneumococcal conjugate vaccine. 5. PCV13 can reduce the level of systemic inflammation within 1 year after its application.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jun-hua Xue ◽  
Ke-liang Zhan ◽  
Xuan-hong Du ◽  
Qian Ma

In view of the damage of dynamic stress to the rock surrounding a mine roadway during coal mining, based on the actual geological conditions of Zhuji mine in Huainan, China, a UDEC model was established to study the influences of the thickness and strength of the direct roof above the coal seam and the anchorage effect on the stability of the roadway. The failure mechanism and effect of the dynamic stress on the rock surrounding a mine roadway were revealed. Under dynamic stress, cracks appear near the side of the roadway where the stress is concentrated. These cracks rapidly expand to the two sides of coal and rock mass. At the same time, the coal and rock mass at the top of the roadway fall, and finally, the two sides of coal and rock mass were broken and ejected into the roadway, causing a rock burst. However, when the same dynamic stress is applied to the roadway after supports are installed, there is no large-deformation failure in the roadway, which shows that, under certain conditions, rock bolting can improve the stability and seismic resistance of the surrounding coal and rock mass. Furthermore, by simulating the failure of surrounding rock with different strengths and thicknesses in the immediate roof, it is found that the thinner the roof, the greater the influence of the dynamic stress on the roadway; the stronger the roof is, the more likely the rock burst will occur with greater intensity under the same dynamic stress. A numerical simulation method was used to analyze the factors influencing rock bursting. The results provide a theoretical basis for research into the causes and prevention of rock bursts in deep mining areas.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhigang Tao ◽  
Senlin Luo ◽  
Di Wu ◽  
Yafei Qiao ◽  
Gang Zhao ◽  
...  

The grotto rock mass is a type of cave structure, formed under the complex forces of environment, geology, and human interventions. Many scholars have carried out a lot of work in the protection of cultural relics. However, the research on detection and monitoring methods based on the parametric evolution system remains incomplete. In recent years, with the intersection and integration of disciplines, IoT (IoT: Internet of Things) systems and sensor technologies have developed rapidly. Under this background, a new monitoring system suitable for the protection of cultural relics was independently developed and applied to the protection and research work of Yuanjue rock cave, and the system was corrected and improved in practice. In this paper, according to the complex force characteristics of the sandstone roof of the Yuanjue rock cave at Dazu Rock Carvings and the geological conditions. Initially, a detailed survey of the geological conditions of the Yuanjue rock cave area was conducted; furthermore, according to the unique structural and load characteristics of the outer and inner surfaces of the roof, the monitoring methods and principles of each main control factor were explored, while the layout of monitoring points was optimized; finally, based on the microsensing technology, intelligent high-precision sensing hardware was installed and debugged for each main control factor, while the network was formed to form a multisource monitoring IoT system for the roof stability of the circular sense hole. After nearly half a year of continuous monitoring, the deformation and denudation rules of the roof of Yuanjue Cave were revealed, and a new approach of evaluating roof stability was proposed. This research provided technical support and research ideas for monitoring the stability of similar cultural relics.


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