scholarly journals Research on Key Factors Influencing Surface Subsidence of Paste Backfilling Mining in Thick Coal Seam of Deep Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Meng Zhang ◽  
Hui He ◽  
Xin Jin ◽  
Yonglong Qu ◽  
Hongjun Guo
Keyword(s):  
Coal Seam ◽  
Reference Value ◽  
Field Research ◽  
Surface Subsidence ◽  
Systematic Research ◽  
Solid Waste Disposal ◽  
Key Factors ◽  
Thick Coal Seam ◽  
Deep Mine ◽  
Key Factor

The research on the key factors of surface subsidence in paste backfilling mining of thick coal seam in deep mine is a complex system engineering, which involves mining, backfilling, support, subsidence, safety, and other aspects. At present, there is no systematic research on the key factors of surface subsidence in paste backfilling mining of thick coal seam more than 6 meters in a deep mine. In this paper, field research, laboratory experiments, theoretical analysis, and other research methods are used to carry out the research about 3# coal seam under buildings in the Lu’an area. The main conclusions are as follows: through the construction of the fuzzy extension model of surface subsidence in paste backfilling mining, five types of surface subsidence are obtained, including overburden structure, roof subsidence before backfilling, nonbackfilling account, the strength of filling body, and backfilling technology. It is the key factor to control the surface subsidence; the optimization measures are given to provide a reference for the reasonable design of paste backfilling mining in other working faces. The research conclusion has a certain reference value for solving a series of problems such as coal resources under buildings, solid waste disposal, controlling strata and surface movement, improving the recovery rate of mine resources, and extending the service life of mine.

scholarly journals Dynamic Changes in Surface Damage Induced by High-Intensity Mining of Shallow, Thick Coal Seams in Gully Areas

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Jianwei Li ◽  
Xintian Li ◽  
Changyou Liu ◽  
Xiangye Wu
Keyword(s):  
Coal Seam ◽  
High Intensity ◽  
Three Dimensional ◽  
Surface Damage ◽  
Surface Subsidence ◽  
Dynamic Changes ◽  
Thick Coal Seam ◽  
Amplification Ratio ◽  
Geological Disasters ◽  
Seam Mining

This study proposes a novel approach to study the mechanism of mining and dynamic changes in surface subsidence and geological hazard-prone regions caused by shallow, thick coal seam mining in gully areas. This approach combines field observation, three-dimensional modeling, numerical simulation, and theoretical analysis based on the conditions of the Chuancao Gedan coal mine. The in situ stress field of coalbeds is influenced by the gully terrain. Shear stress becomes concentrated on the surface, causing geological disasters such as landslides and collapse of gully slopes. High-intensity mining activities increase the concentration and are more likely to cause such geological disasters. The influence area and severity vary dynamically with the expansion of the excavation area. With the continuous expansion of coal seam mining, the amplification ratio η (the ratio of the maximum impact range of surface subsidence and the mined-out area) first increased to 3.35, then decreased, and finally reached a constant value of 2.1. The principle of road line selection is proposed based on an analysis of surface subsidence and gully slope stability on the goaf edge. The principle of subsection reinforcement of the gully slope under the dynamic influence of coal seam mining is also determined.

scholarly journals Cooperative Control Mechanism of Long Flexible Bolts and Blasting Pressure Relief in Hard Roof Roadways of Extra-Thick Coal Seams: A Case Study

2021 ◽  
Vol 11 (9) ◽  
pp. 4125
Author(s):  
Zhe Xiang ◽  
Nong Zhang ◽  
Zhengzheng Xie ◽  
Feng Guo ◽  
Chenghao Zhang
Keyword(s):  
Coal Seam ◽  
Cooperative Control ◽  
Field Tests ◽  
Surrounding Rock ◽  
Deep Hole ◽  
Coal Seams ◽  
Thick Coal Seam ◽  
Structure Damage ◽  
Hard Roof

The higher strength of a hard roof leads to higher coal pressure during coal mining, especially under extra-thick coal seam conditions. This study addresses the hard roof control problem for extra-thick coal seams using the air return roadway 4106 (AR 4106) of the Wenjiapo Coal Mine as a case study. A new surrounding rock control strategy is proposed, which mainly includes 44 m deep-hole pre-splitting blasting for stress releasing and flexible 4-m-long bolt for roof supporting. Based on the new support scheme, field tests were performed. The results show that roadway support failure in traditional scenarios is caused by insufficient bolt length and extensive rotary subsidence of the long cantilever beam of the hard roof. In the new proposed scheme, flexible 4-m-long bolts are shown to effectively restrain the initial expansion deformation of the top coal. The deflection of the rock beam anchored by the roof foundation are improved. Deep-hole pre-splitting blasting effectively reduces the cantilever distance of the “block B” of the voussoir beam structure. The stress environment of the roadway surrounding rock is optimized and anchorage structure damage is inhibited. The results provide insights regarding the safe control of roadway roofs under extra-thick coal seam conditions.

scholarly journals Optimize Design of Run-Flat Tires by Simulation and Experimental Research

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 474
Author(s):  
Huaqiao Liu ◽  
Yiren Pan ◽  
Huiguang Bian ◽  
Chuansheng Wang
Keyword(s):  
Stress Distribution ◽  
Energy Loss ◽  
Successful Implementation ◽  
Performance Tests ◽  
Key Factors ◽  
Heat Accumulation ◽  
Factors Affecting ◽  
Structural Rigidity ◽  
Key Factor ◽  
Durability Testing

In this study, the two key factors affecting the thermal performance of the insert rubber and stress distribution on the tire sidewall were analyzed extensively through various performance tests and simulations to promote the development of run-flat tires. Four compounds and two structures of insert rubber were designed to investigate the effects of heat accumulation and stress distribution on durability testing at zero pressure. It was concluded that the rigidity and tensile strength of the compound were negatively correlated with temperature. The deformation was a key factor that affects energy loss, which could not be judged solely by the loss factor. The stress distribution, however, should be considered in order to avoid early damage of the tire caused by stress concentration. On the whole, the careful balance of mechanical strength, energy loss, and structural rigidity was the key to the optimal development of run-flat tires. More importantly, the successful implementation of the simulations in the study provided important and useful guidance for run-flat tire development.

From detente to containment: the emergence of Iran's new Saudi strategy

2021 ◽  
Author(s):  
Hassan Ahmadian ◽  
Payam Mohseni
Keyword(s):  
Decision Making ◽  
Saudi Arabia ◽  
Middle East ◽  
Strategic Decision ◽  
Key Factors ◽  
Peace And Conflict ◽  
Key Factor ◽  
Decision Making Factors ◽  
Containment Strategy ◽  
The Persian Gulf

Abstract Iran's strategy with respect to Saudi Arabia is a key factor in the complex balance of power of the Middle East as the Iranian–Saudi rivalry impacts the dynamics of peace and conflict across the region from Yemen to Syria, Lebanon, Iraq and Bahrain. What is Iranian strategic thinking on Saudi Arabia? And what have been the key factors driving the evolution of Iranian strategy towards the Kingdom? In what marks a substantive shift from its previous detente policy, we argue that Tehran has developed a new containment strategy in response to the perceived threat posed by an increasingly prox-active Saudi Arabia in the post-Arab Spring period. Incorporating rich fieldwork and interviews in the Middle East, this article delineates the theoretical contours of Iranian containment and contextualizes it within the framework of the Persian Gulf security architecture, demonstrating how rational geopolitical decision-making factors based on a containment strategy, rather than the primacy of sectarianism or domestic political orientations, shape Iran's Saudi strategy. Accordingly, the article traces Iranian strategic decision-making towards the Kingdom since the Islamic Revolution of 1979 and examines three cases of Iran's current use of containment against Saudi Arabia in Syria, Yemen and Qatar.

Grit as a Key Factor in the Ability of Students to Achieve Productive Global Field Research

2021 ◽  
Author(s):  
Lindsey J. Mattick ◽  
Breanne E. Lott ◽  
Christina E. Baum ◽  
Amr S. Soliman
Keyword(s):  
Field Research ◽  
Global Field ◽  
Key Factor

Responsible innovation and social innovation: toward an integrative research framework

2019 ◽  
Vol 46 (6) ◽  
pp. 742-755 ◽  
Author(s):  
Karsten Bolz ◽  
Anne de Bruin
Keyword(s):  
Social Innovation ◽  
Field Research ◽  
Responsible Innovation ◽  
Systematic Research ◽  
Content Type ◽  
Policy Practice ◽  
Integrative Framework ◽  
Integrative Research ◽  
Conceptual Paper ◽  
Innovation Study

PurposeResponsible innovation (RI) and social innovation (SI) are two fields of innovation study experiencing burgeoning policy, practice and research interest. Despite this rapid rise in popularity, the scholarly literature in these two related areas of innovation study remains quite separate, stymieing the growth of shared research insights. The purpose of this paper is to propose a pragmatic, process-based framework that lends itself to advancing systematic research in both fields while retaining their distinct identities.Design/methodology/approachThis conceptual paper outlines an analogy-inspired framework that builds on the logical thinking put forward by Philosopher Willard Van Orman Quine in 1962. It focusses on key processes that cross-cut both fields.FindingsReflexivity, collaboration and design are identified as three broad core processes that span both the RI and SI fields and form the basis of an integrative framework that highlights the scope for cross-field research pollination.Originality/valueThe literature that draws these two fields together is virtually non-existent. The paper uses analogy to facilitate awareness of the parallels between these two areas of innovation study. The integrative framework put forward in the paper is of value for advancing cumulative research in innovation fields of critical importance to the society.

Gas drainage technology of high gas and thick coal seam

2009 ◽  
Vol 15 (3) ◽  
pp. 299-303 ◽  
Author(s):  
Tian-cai He ◽  
Hai-gui Li ◽  
Hai-jun Zhang
Keyword(s):  
Coal Seam ◽  
Gas Drainage ◽  
Thick Coal Seam

scholarly journals Key Factors of Sustainability for Smartphones Based on Taiwanese Consumers’ Perceived Values

2018 ◽  
Vol 10 (12) ◽  
pp. 4446 ◽  
Author(s):  
Jui-Che Tu ◽  
Xiu-Yue Zhang ◽  
Sin-Yi Huang
Keyword(s):  
Service Quality ◽  
Purchase Intention ◽  
Perceived Value ◽  
Income Level ◽  
Demographic Variables ◽  
Key Factors ◽  
Significant Difference ◽  
Perceived Values ◽  
Perceived Price ◽  
Key Factor

The rapid growth of smartphones over recent decades has brought a large amount of e-waste as well as an increased carbon footprint. Facing severe environmental issues, sustainable development of smartphones has become a particularly important public concern. The main aim of this study was to clarify the key factor of sustainability for smartphones based on Taiwanese consumers’ perceived values. Apple’s iPhone was taken as an example. First, key factors of perception that smartphone consumers valued the most in terms of sustainable practice were extracted through a factor analysis. Second, demographic differences related to these key factors were investigated through t-test and one-way ANOVA analyses; demographic variables were gender, age, education level, occupation, and income level. The results were as follows: (1) the key factors were “recognition”, “brand advantage”, “service quality”, “usage period”, and “perceived price”; (2) there was a significant difference between genders on the key factors of perceived value (“recognition”, “brand advantage”, and “perceived price”). Specifically, females have higher perceived values of “recognition”, “brand advantage”, and “perceived price” than males; (3) there was a significant effect of income level on the key factor (“perceived price”) of perceived value. Specifically, respondents with an income level of NTD15,001–30,000 had a higher perceived value of “perceived price” than respondents earning NTD30,001–45,000. Among the five key factors, “recognition” and “brand advantage” are primary factors influencing purchase motivation; “recognition”, “brand advantage”, and “service quality” are primary factors that could influence brand loyalty; “perceived price” is the primary factor that affects purchase intention. This study contributes to the green market segmentation of smartphones. The limitations of the study relate to the size and distribution of the samples.

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