Study on Parameters of Support for Control of Roof Fall and Rib Spalling in Large Fully Mechanized Top Coal Caving End Face

2012 ◽  
Vol 616-618 ◽  
pp. 421-425 ◽  
Author(s):  
Fu Lian He ◽  
Xiao Ming Wang ◽  
De Quan Zhang ◽  
Shang Sen He
Keyword(s):  
Numerical Simulation ◽  
Regression Analysis ◽  
Rock Mass ◽  
Mechanical Model ◽  
Key Factors ◽  
Factors Affecting ◽  
Roof Fall ◽  
Effect Of Support

Key factors affecting the control of roof fall and rib spalling are identified relying on the statistics for characteristics of roof fall and rib spalling distribution, and the regression analysis of the relationships of roof fall and rib spalling to support parameters by measuring actual ground pressures. The effect of support in controlling roof fall and rib spalling is analyzed by setting up a caving arch mechanical model of cataclastic coal and rock mass on fully mechanized caving face, and the key parameters of support are also determined using numerical simulation.

scholarly journals Key Factors Affecting the Deformation and Failure of Surrounding Rock Masses in Large-Scale Underground Powerhouses

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Meng Wang ◽  
Jia-wen Zhou ◽  
An-chi Shi ◽  
Jin-qi Han ◽  
Hai-bo Li
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Surrounding Rock ◽  
Rock Masses ◽  
Affecting Factors ◽  
Key Factors ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Factors Affecting ◽  
Geological Conditions

The stability of the surrounding rock masses of underground powerhouses is always emphasized during the construction period. With the general trends toward large-scale, complex geological conditions and the rapid construction progress of underground powerhouses, deformation and failure issues of the surrounding rock mass can emerge, putting the safety of construction and operation in jeopardy and causing enormous economic loss. To solve these problems, an understanding of the origins and key affecting factors is required. Based on domestic large-scale underground powerhouse cases in the past two decades, key factors affecting the deformation and failure of the surrounding rock mass are summarized in this paper. Among these factors, the two most fundamental factors are the rock mass properties and in situ stress, which impart tremendous impacts on surrounding rock mass stability in a number of cases. Excavation is a prerequisite of surrounding rock mass failure and support that is classified as part of the construction process and plays a pivotal role in preventing and arresting deformation and failure. Additionally, the layout and structure of the powerhouse are consequential. The interrelation and interaction of these factors are discussed at the end of this paper. The results can hopefully advance the understanding of the deformation and failure of surrounding rock masses and provide a reference for design and construction with respect to hydroelectric underground powerhouses.

scholarly journals Determination of the Ultimate Underground Mining Depth considering the Effect of Granular Rock and the Range of Surface Caving

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Rongxing He ◽  
Jing Zhang ◽  
Yang Liu ◽  
Delin Song ◽  
Fengyu Ren
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Mechanical Model ◽  
Surface Deformation ◽  
Underground Mining ◽  
Mining Area ◽  
Open Pit ◽  
Open Pit Mining ◽  
Mining Depth

Continuous mining of metal deposits leads the overlying strata to move, deform, and collapse, which is particularly obvious when open-pit mining and underground mining are adjacent. Once the mining depth of the adjacent open-pit lags severely behind the underground, the ultimate underground mining depth needs to be studied before the surface deformation extends to the open-pit mining area. The numerical simulation and the mechanical model are applied to research the ultimate underground mining depth of the southeast mining area in the Gongchangling Iron mine. In the numerical simulation, the effect of granular rock is considered and the granular rock in the collapse pit is simplified as the degraded rock mass. The ultimate underground mining depth can be obtained by the values of the indicators of surface movement and deformation. In the mechanical model, the modified mechanical model for the progressive hanging wall caving is established based on Hoke’s conclusion, which considers the lateral pressure of the granular rock. Using the limiting equilibrium analysis, the relationship of the ultimate underground mining depth and the range of surface caving can be derived. The results show that the ultimate underground mining depth obtained by the numerical simulation is greater than the theoretical calculation of the modified mechanical model. The reason for this difference may be related to the assumption of the granular rock in the numerical simulation, which increases the resistance of granular rock to the deformation of rock mass. Therefore, the ultimate underground mining depth obtained by the theoretical calculation is suggested. Meanwhile, the surface displacement monitoring is implemented to verify the reasonability of the ultimate underground mining depth. Monitoring results show that the indicators of surface deformation are below the critical value of dangerous movement when the underground is mined to the ultimate mining depth. The practice proves that the determination of the ultimate underground mining depth in this work can ensure the safety of the open-pit and underground synergetic mining.

scholarly journals Empirical regularities investigation of rock mass discharge by explosion on the free surface of a pit bench

2021 ◽  
Vol 249 ◽  
pp. 334-341
Author(s):  
Igor Alenichev ◽  
Ruslan Rakhmanov
Keyword(s):  
Rock Mass ◽  
Slope Angle ◽  
Rock Breaking ◽  
Key Factors ◽  
Technological Parameters ◽  
Factors Affecting ◽  
Geological Conditions ◽  
Empirical Regularities ◽  
Main Discharge ◽  
Mass Discharge

Minimizing the discharge of blasted rock mass into the developed space of the pit is a very relevant area for study, as it allows to increase the processability of work and reduce the cost of mining. The article presents the results of experimental industrial explosions, during which the study of this issue was conducted. The main purpose of the work was to establish the key factors affecting the volume of rock mass discharge to the pit haulage berm. During the analysis of the world experience of research on this topic, the key factors affecting the formation of collapse and discharge – natural and technological – are identified. The method of conducting experiments and collecting data for analyzing the influence of technological parameters of location, charging and initiation of wells on the volume of rock mass discharge is described. It is established that the main discharge to the pit haulage berm is formed by the volume of rock mass limited by the prism of the slope angle. With a sufficient rock mass displacement from the edge of the bench crest towards the center of the block, only the wells of the 1st and 2nd rows participate in the discharge formation. Empirical dependences of the total volume of rock mass discharge on the length of the block along the bench crest, the specific consumption of explosives, the size of a rock piece P50 and the rate of rock breaking are obtained. The obtained results can be used to design the parameters of the drilling and blasting operations (DBO), as well as to predict and evaluate the possible consequences of a mass explosion in similar mining and geological conditions.

Numerical Simulation of Unloading Zone Division for Excavated Rock Slope

2014 ◽  
Vol 919-921 ◽  
pp. 701-705
Author(s):  
Xing Xia Wang ◽  
Chen Jing Deng
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Rock Slope ◽  
Stress Component ◽  
Key Factors ◽  
Slope Excavation ◽  
Before And After ◽  
Calculation Results ◽  
Slope Rock ◽  
Zone Division

Excavation unloading zone corresponds to stress decreased area of slope rock mass after excavation. Quality of slope rock mass in this area will be degraded due to excavation disturbance, and the mechanical parameters of rock mass will be also degraded accordingly. Therefore, determining the range of excavation unloading zone accurately is one of the key factors to ensure the rationality and validity of numerical simulation results of rock slope excavation. In this paper, the range of excavation unloading zone is determined by comparing stress field before and after excavation, choosing stress component perpendicular to excavation face as comparative standard in calculation, which can be calculated by computer program with FLAC software. Stress adjustment of slope rock mass due to excavation is a dynamic and changing progress, so the range of excavation unloading zone is changing during excavation, which can be achieved by a cycling program in numerical simulation. The correctness and usefulness of this method is proved by the calculation results of example analysis.

Dynamic Numerical Simulation for the Problem of Tunnel Rock Mass Large Deformation of a Hydropower Project in the Upper Reaches of Lancang River

2011 ◽  
Vol 250-253 ◽  
pp. 1315-1319
Author(s):  
Yu Sheng Li ◽  
Guang Peng Cao ◽  
Jie Bao
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Large Deformation ◽  
Surrounding Rock ◽  
Underground Engineering ◽  
Rock Mass Structure ◽  
Roof Fall ◽  
Relaxation Stress ◽  
Stress Environment ◽  
Dynamic Numerical Simulation

It is a very effective technology methods that using dynamic numerical simulation of discrete element method to study the large deformation problems of underground engineering rock mass which in the complex rock mass mechanics environmental conditions.Research achievements show that the development of deformation failure of the tunnel surrounding rock and the final convergence stability are mainly controlled by rock mass structure and its stress environment in the special toppling deformation rock mass. Deformation of the rock mass that in the lateral unloading and relaxation and also has a complex rock mass structure developed sustainably and progressivity over time,will eventually seriously damaged in roof fall. The surrounding rock deformation of the tunnel ,which have a good rock mass integrity and do not have the obvious unloading and relaxation stress environment, gradually tended to be stable after the initial deceleration-type development.

scholarly journals Factors Affecting Online Customer Satisfaction: The Sri Lankan Perspective

2019 ◽  
Vol 14 (2) ◽  
pp. 99 ◽  
Author(s):  
Piruni A. Deyalage ◽  
Dushyantha Kulathunga
Keyword(s):  
Regression Analysis ◽  
Customer Satisfaction ◽  
Multiple Regression Analysis ◽  
Conceptual Model ◽  
Customer Service ◽  
Online Shopping ◽  
Website Design ◽  
Sri Lankan ◽  
Key Factors ◽  
Factors Affecting

Customer satisfaction has been identified as an important phenomenon in relation to online shopping.  The investigation of what cause customer satisfaction has become paramount for online businesses. Therefore, the purpose of this study was to identify the determinants of customer satisfaction in an online context. In this study, the authors proposed a conceptual model of customer satisfaction in the online context by identifying the key factors proposed by previous studies, and hypotheses were developed accordingly. The hypotheses were tested through multiple regression analysis, based on a sample of 150 online customers. The study found that customer service, website design and security perception were significantly associated with online customer satisfaction.

Numerical Simulation of the Diffusion of Natural Gas Due to Pipeline Failure

2007 ◽  
Author(s):  
Yanlei Liu ◽  
Jinyang Zheng
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Natural Gas ◽  
Gas Diffusion ◽  
Key Factors ◽  
Species Transport ◽  
Factors Affecting ◽  
Temperature Distributions ◽  
Volumetric Model ◽  
Pipeline Failure

This paper introduces a numerical method to calculate the diffusion of natural gas due to pipeline failure, which provides an effective base for solving the problems of leakage of natural gas. A finite volumetric model and the corresponding numerical algorithm are established by using species transport and reaction module of FLUENT. In this method, several important parameters such as the mole fraction of components, pressure and temperature distributions within the calculating region are predicted to certain accuracy. Based on numerical results, the key factors affecting the natural gas diffusion such as the diameter of the hole and wind speed are also analyzed. The current study presents a clear view in dealing with the leakage of natural gas due to pipeline failure.

Studying the factors of regional insurance market development using the correlation and regression analysis

2020 ◽  
Vol 26 (7) ◽  
pp. 1610-1630
Author(s):  
E.L. Prokop'eva
Keyword(s):  
Regression Analysis ◽  
Federal District ◽  
Insurance Market ◽  
Market Development ◽  
Insurance Markets ◽  
Regression Equations ◽  
Factors Affecting ◽  
Correlation And Regression Analysis ◽  
Country Level ◽  
Inverse Effect

Subject. The article investigates and quantifies factors of insurance markets functioning in Russian regions, and reveals possibilities to manage them. Objectives. The purpose of the study is to substantiate regional factors that determine the specifics of regional insurance market development; to quantify them to increase the efficiency of regional insurance. Methods. The study draws on statistical methods, functional analysis, algorithm development, correlation and regression analysis. Results. I calculated coefficients of pair and multiple correlation with the indicators of insurance markets in the context of the subjects of the Russian Federation, and composed regression equations. Based on the analysis, I determined the algorithm for inverse effect of the insurance market on the economic, social, fiscal and environmental performance of the region, offered appropriate measures aimed at developing the economic potential of the region and its social sphere. Conclusions. The paper considers the case of the Republic of Khakassia, one of depressed subjects in the Siberian Federal District. The developed models can be used for other regions of Russia, given the geographical and economic features of development. The findings may help generate regional strategies for socio-economic development at the country level. The scientific contribution and the novelty of the work consist of systematizing and quantifying the factors affecting the insurance mechanisms of regional markets, and assessing the inverse effect of insurance mechanisms on integrated development of the region.

Regression analysis of indicators of a numerical experiment to determine the cooling time of oil

2020 ◽  
pp. 89-97
Author(s):  
A. U. Yakupov ◽  
D. A. Cherentsov ◽  
K. S. Voronin ◽  
Yu. D. Zemenkov
Keyword(s):  
Regression Analysis ◽  
Computer Experiment ◽  
Calculation Model ◽  
Cooling Time ◽  
Regression Coefficients ◽  
Fisher Criterion ◽  
Empirical Relationships ◽  
Factors Affecting ◽  
Oil Pipeline ◽  
Significant Regression

The article performed the processing of the results of a computer experiment to determine the cooling time of oil in a stopped oil pipeline. We proposed a calculation model in previous works that allows you to simulate the process of cooling oil.There was a need to verify the previously obtained results when conducting a laboratory experiment on a stand with soil. To conduct the experiment, it was necessary to conduct the planning of the experiment. The factors affecting the cooling time of oil in the oil pipeline, which will vary in the proposed experiment, are determined, empirical relationships are established. A regression analysis was carried out, and the dispersion homogeneity was checked using the Cochren criterion. The estimates of reproducibility variances are calculated. The adequacy hypothesis was tested using the Fisher criterion. Significant regression coefficients are established.

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