Multi-factor evaluation for the water yield properties of coal floor aquifers, based on GIS

2016 ◽  
Vol 11 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Bo Li ◽  
Qiang Wu ◽  
Yulong Chen ◽  
Ganlu Wang ◽  
Lei Xu
Keyword(s):  
Drilling Fluid ◽  
Water Inrush ◽  
Research Area ◽  
Specific Yield ◽  
Water Yield ◽  
Groundwater Inrush ◽  
Evaluation Indexes ◽  
Factor Evaluation ◽  
Index Weight ◽  
Aquifer Yield

Groundwater inrush in mines directly threatens safe coal production. Aquifer yield plays a crucial role during water inrush. Significant accidents occur in areas where aquifer yields are strong. The yield of an aquifer is influenced by many things and, in this study, five for which data are easily acquired were selected as evaluation indices for coal-seam floor aquifer yield. They comprise specific yield, permeability, drilling fluid consumption, aquifer thickness, and fault and fold distribution. Based on these indices, a comprehensive model for evaluating water yield was constructed. Using the Ordovician limestone aquifer below the coal floor of Danhou coal mine, Hebei province, China, as an example, index data relating to aquifer yield were collected and the index weight determined. A geographic information system was used to prepare a thematic map for each driving factor and, subsequently, to superimpose them. Comprehensive water yield evaluation indexes were obtained and, finally, a zonal map of different water yield properties was developed for the research area.

scholarly journals Analysis of Key Factors Affecting Water Disaster in Deep Mining and Establishment of a Water Disaster Evaluation Method Suitable for Different Mining Depths

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jianghui He ◽  
Wenping Li ◽  
Wei Qiao ◽  
Zhi Yang ◽  
Qiqing Wang
Keyword(s):  
Water Inrush ◽  
Assessment Method ◽  
New Method ◽  
Specific Yield ◽  
Water Yield ◽  
Deep Mining ◽  
Hydrogeological Characteristics ◽  
Formula Method ◽  
Water Disaster

Deep mining is the current and future mining focus in the coalfield of North China. Therefore, it is necessary to establish a water inrush assessment method suitable for deep mining. The conventional water inrush coefficient ( T ) method is simple to use, but its accuracy is low when the mining depth is very small or large because it neglects the role of the aquifer water yield. The main purpose of this paper is to introduce a simple water inrush risk assessment method that is more applicable in deep mining than the T method. In this study, the hydrogeological characteristics in deep mining were studied and the role of the aquifer water yield in water inrush was analyzed. Afterwards, an improved T method considering the aquifer specific yield ( q ) was established. In the new method, the critical water inrush coefficient changes with changing q following a negative correlation. The parameter thresholds were determined based on systematic data analyses of 186 mining cases. The results of the statistical analysis show that the accuracy of the new method at different mining depths is higher than that of the T method.

scholarly journals Mechanism of groundwater inrush hazard caused by solution mining in a multilayered rock-salt-mining area: a case study in Tongbai, China

2018 ◽  
Vol 18 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Bin Zeng ◽  
Tingting Shi ◽  
Zhihua Chen ◽  
Liu Xiang ◽  
Shaopeng Xiang ◽  
...  
Keyword(s):  
Rock Salt ◽  
Water Inrush ◽  
Simulation Method ◽  
Mining Area ◽  
Geological Structure ◽  
Pollution Source ◽  
Groundwater Inrush ◽  
Solution Mining ◽  
Brine Leakage ◽  
Salt Mining

Abstract. The solution mining of salt mineral resources may contaminate groundwater and lead to water inrush out of the ground due to brine leakage. Through the example of a serious groundwater inrush hazard in a large salt-mining area in Tongbai County, China, this study mainly aims to analyse the source and channel of the inrushing water. The mining area has three different types of ore beds including trona (trisodium hydrogendicarbonate dihydrate, also sodium sesquicarbonate dihydrate, with the formula Na2CO3 × NaHCO3 × 2H2O, it is a non-marine evaporite mineral), glauber (sodium sulfate, it is the inorganic compound with the formula Na2SO4 as well as several related hydrates) and gypsum (a soft sulfate mineral composed of calcium sulfate dihydrate, with chemical formula CaSO4 × 2H2O). Based on characterisation of the geological and hydrogeological conditions, the hydrochemical data of the groundwater at different points and depths were used to analyse the pollution source and the pollutant component from single or mixed brine by using physical–chemical reaction principle analysis and hydrogeochemical simulation method. Finally, a possible brine leakage connecting the channel to the ground was discussed from both the geological and artificial perspectives. The results reveal that the brine from the trona mine is the major pollution source; there is a NW–SE fissure zone controlled by the geological structure that provides the main channels through which brine can flow into the aquifer around the water inrush regions, with a large number of waste gypsum exploration boreholes channelling the polluted groundwater inrush out of the ground. This research can be a valuable reference for avoiding and assessing groundwater inrush hazards in similar rock-salt-mining areas, which is advantageous for both groundwater quality protection and public health.

scholarly journals Application of TOPSIS Method Based on Entropy Weight -Delphi in the Evaluation of Teachers’ “double-qualified” Ability

2020 ◽  
Vol 165 ◽  
pp. 06050
Author(s):  
Weixia Wang ◽  
He Jun
Keyword(s):  
Evaluation System ◽  
Evaluation Model ◽  
Topsis Method ◽  
Entropy Weight ◽  
Chinese Library Classification ◽  
Evaluation Indexes ◽  
Energy Evaluation ◽  
Entropy Weight Method ◽  
Weight Method ◽  
Index Weight

In order to improve the rationality and fairness of Teachers’ “Double-qualified” Ability, the article establishes an evaluation model based on 14 evaluation indexes of teachers’ “double-qualified” ability. it adopts Delphi - entropy weight method to weight the evaluation index, and then combines TOPSIS method to evaluate the evaluation object. In the evaluation of TOPSIS method, the traditional TOPSIS weight method was improved, and the entropy weight-delphi method was used to determine the index weight, which was a combination of subjective and objective, making the evaluation system more objective, scientific and reasonable.It not only avoids the subjectivity of decision makers and limitations, but also eliminates the phenomenon of indexes in common impact assessment results and finally applies it to a university teacher “Double division and triple energy” evaluation system, to provide theoretical basis and feasibility analysis for the “double type” teachers team construction. Chinese library classification number: O224 Document identification code: A

Evaluation Indexes of Environmental Protection and a Novel System for Offshore Drilling Fluid

2013 ◽  
Vol 32 (4) ◽  
pp. 455-461 ◽  
Author(s):  
S. X. Xie ◽  
G. C. Jiang ◽  
M. Chen ◽  
Z. Y. Li ◽  
H. Mao ◽  
...  
Keyword(s):  
Environmental Protection ◽  
Drilling Fluid ◽  
Offshore Drilling ◽  
Evaluation Indexes

scholarly journals Risk Assessments of Water Inrush from Coal Seam Floor during Deep Mining Using a Data Fusion Approach Based on Grey System Theory

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yaru Guo ◽  
Shuning Dong ◽  
Yonghong Hao ◽  
Zaibin Liu ◽  
Tian-Chyi Jim Yeh ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Coal Mine ◽  
Drilling Fluid ◽  
Water Pressure ◽  
Water Inrush ◽  
Grey System Theory ◽  
Directional Drilling ◽  
Grey System ◽  
Highly Correlated

With the increase in depth of coal mining, the hydrogeological complexity largely increases and water inrush accidents happen more frequently. For the safety of coal mining, horizontal directional drilling and grouting techniques have been implemented to detect and plug the fractures and conduits that deliver high-pressure groundwater to coal mine. Taking the grouting engineering performed at Xingdong coal mine at 980 m below sea level as an example, we collected the data of grouting quantity, the loss of drilling fluid, gamma value, water temperature, average water absorption, distance between grouting loss points, water pressure on coal seam floor, and aquifuge thickness at 90 boreholes in the mine to conduct grey relational analysis, first. The analysis showed that the grouting quantity was highly correlated with all other factors. Subsequently, grey system evaluation was used to evaluate the risk of water inrush from the coal seam floor. The results of risk analysis illustrated that three water inrushes from Ordovician limestone occurred in mining face 2127, 2125, and 2222 in the study area were all located in the area with a risk score higher than 65. Through grouting, the identified cracks were effectively blocked and waterproof layers beneath the coal seam floors were constructed to reduce the threat of water inrush. By comparing the risk assessment results with three water inrush cases before grouting operation, we found that water inrush areas were consistent with the area of higher risk.

Power Shift Control of High-Power Tractor Based on Pattern Search

2020 ◽  
Vol 36 (4) ◽  
pp. 565-578
Author(s):  
Guang Xia ◽  
Xinghai Yu ◽  
Xiwen Tang ◽  
Linfeng Zhao ◽  
Baoqun Sun
Keyword(s):  
Evaluation System ◽  
Sliding Wear ◽  
Pattern Search ◽  
Shift Quality ◽  
Evaluation Indexes ◽  
Shift Control ◽  
Output Torque ◽  
Power Shift ◽  
Factor Evaluation ◽  
Three Factor

Highlights This article presents a multiobjective optimization function of power shift quality that uses the calculation formulas of sliding wear work, impact degree, and output torque derived from the analysis of split-phase dynamics. The calculation formulas of impact degree, sliding wear work, and output torque of each phase are derived, and a three-factor evaluation system of power shift quality is constructed. A pattern-search-based optimization method of power shift quality is proposed on the basis of the three-factor evaluation system of power shift quality. The power shift control based on pattern search algorithm optimizes the shift quality evaluation indexes and effectively improves the power shift quality of high-power tractors. Abstract . This study conducts a dynamic analysis of power shift by analyzing the key influencing factors of power shift quality. The power shift process is divided into low gear torque, sliding wear, and high gear torque phases. The calculation formulas of impact degree, sliding wear work, and output torque of each phase are derived, and a three-factor evaluation system of power shift quality is constructed. A pattern-search-based optimization method of power shift quality is proposed on the basis of the three-factor evaluation system of power shift quality. A multi-objective optimization function of shift quality is constructed using the linear change law expression of clutch oil pressure and the calculation of shift quality evaluation indexes of each phase. The multi-objective function is pretreated using a weighted coefficient method, and the change rule of clutch oil pressure is accurately optimized. Simulation and experimental results show that the power shift control based on pattern search algorithm optimizes the evaluation indexes of each shift quality and effectively improves the power shift quality of high-power tractors. Keywords: Pattern search, Power shift, Shift quality, Split-phase dynamics.

Research on the Height of Water-Flowing Fractured Zone under the Weak Roof Strata and Fully Mechanized Caving Condition

2015 ◽  
Vol 1092-1093 ◽  
pp. 1448-1454
Author(s):  
Yan Zhang
Keyword(s):  
Coal Mine ◽  
Drilling Fluid ◽  
Water Inrush ◽  
Test Results ◽  
Similar Material ◽  
Fractured Zone ◽  
Working Face ◽  
Observation Method ◽  
Roof Strata ◽  
Similar Material Simulation

The first working face production has suspend because of the great roof water inrush in Mindongyi coal mine, which has weak roof strata and mining use the fully mechanized caving method. In order to detect the height of water-flowing fractured zone, loses of drilling fluid observation method has carried on the flied test, the results showed that while the full-mechanized caving mining thickness is 7.7 m, the height of water-flowing fractured zone is 79.78 m, and the ratio of height to thickness is 10.36, meanwhile, the numerical simulation and similar material simulation have proved the test results are correct. The study enriched the domestic research fruits of the height of water flowing fractured zone, and provided technical references for Mindongyi coal mine mining.

Evaluation Framework and Method of the Intelligent Behaviors of Unmanned Ground Vehicles Based on AHP Scheme

2014 ◽  
Vol 721 ◽  
pp. 476-480 ◽  
Author(s):  
Xin Zhang ◽  
Yan An Zhao ◽  
Li Gao ◽  
Dong Hao Hao
Keyword(s):  
Evaluation System ◽  
Evaluation Method ◽  
Evaluation Framework ◽  
Evaluation Index System ◽  
Unmanned Ground Vehicles ◽  
Ground Vehicles ◽  
Scoring Method ◽  
Evaluation Indexes ◽  
Intelligent Behavior ◽  
Index Weight

In order to provide basis and standards to the research on unmanned driving behaviors, a more thorough evaluation system of Intelligent Behavior for Unmanned Ground Vehicles needs to come forward. The intelligent behavior of unmanned ground vehicles in pedestrian crossing scenario is taken as an example in this paper. By using building and analyzing evaluation index system, this paper proposes an evaluation method that can comprehensively expressed the technological performance of unmanned ground vehicles based on Analytic Hierarchy Process (AHP). Compared with traditional methods, this evaluation method takes index weight into sufficient conderations and is more objective. The method properly works out with index weight of specific scenarios that reflects the actual situations. The establishment of comprehensive scoring method objectively and conveniently turns the performances of unmanned ground vehicle into scores, so that the results can be compared and ranked directly. Last but not least, a certain participating vehicle is used for case study. The result proves aforementioned method to be practical, reliable, convenient and logical. It not only evaluates the assessment comprehensively, but also evaluates the index separately to guide researchers to find out the defects of unmanned driving vehicle evaluation indexes and point out ways to improve them.

scholarly journals Water Inrush Risk Assessment Based on AHP and Advance Forecast Approach: A Case Study in the Micangshan Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Tao Song ◽  
Jun Zeng ◽  
Jiaji Ma ◽  
Chunchi Ma ◽  
Tianbin Li ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Evaluation Model ◽  
Water Inrush ◽  
Prediction Method ◽  
Assessment Method ◽  
Early Assessment ◽  
Analytic Hierarchy ◽  
Effective Prevention ◽  
Evaluation Indexes ◽  
Tunnel Design

Water inrush is a serious geological disaster in tunnel. For the effective prevention and control of the occurrence of water inrush, a static-dynamic water inrush risk assessment method is proposed by considering the Micangshan tunnel as an example. First, four possible types of water inrush phenomenon are identified based on the geological and hydrogeological conditions of the tunnel: water inrush in water-bearing cracks, fault fracture zones, karst pipelines, and karst caves. Next, evaluation indexes that affect water inrush are determined. By combining the index weight value calculated by analytic hierarchy process (AHP) with the index quantitative value, the static water inrush disaster evaluation model is established, which provides a basis for tunnel design. Finally, with the combination of the static evaluation model and advanced forecast method, a dynamic risk prediction method of water inrush is established, which provides guidance for safe construction. The results confirm that the proposed method is a reliable theoretical basis for early assessment and prediction of tunnel water inrush disasters.

scholarly journals Evaluation of the Risk of Water Gushing（Inrush）in Aquifer of Coal Seam Roof Based on "Three Diagram Method" – a Case Study in Hu Jiahe Coal Mine,china

2020 ◽  
Author(s):  
Enke Hou ◽  
Xing Yao ◽  
Xiaoyang Che
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracture ◽  
Fracture Zone ◽  
Permeability Coefficient ◽  
Comprehensive Evaluation ◽  
Water Inrush ◽  
Research Area ◽  
Index Method ◽  
Diagram Method ◽  
Structure Index

Abstract Coal seam roof inrush phenomenon is common in Jurassic coalfield in China. In order to evaluate accurately the risk of coal seam roof water inrush (CSRWI) it needs to analyze the degree of water rich degree and crack height of strata aquifer. Based on the combined weight-TOPSIS theory, this paper intends to adopt the 8 factors of aquifer thickness, lithological structure index, core adoption rate and permeability coefficient, and TDS from the three aspects of aquifer lithology, hydrology and hydrochemical characteristics. As an evaluation index of the water richness of the aquifer in the Luohe Formation, By using the method of GI method and independent weight method subjective and objective weights influencing aquifer water rich control factors are determined and then weights are coupled by differential maximization theory.Based on GIS spatial analysis technology, an evaluation model of aquifer water rich in coal seam roof aquifer was established and verified by field measured hydrological pore data.Through empirical value calculation of coal seam roof crack height and further refinement of hydraulic fracture zone spread across aquifer floor and combined with aquifer degree of water enrichment and roof cracking degree to carry out comprehensive evaluation of the risk of CSRWI. The most important factors affecting the degree of water enrichment of aquifers are lithological structure index and permeability coefficient, followed by TDS. Compared with water-rich index method, the water-rich degree of aquifer can be effectively determined based on combination weight and TOPSIS method. Moreover, subdivision of roof crack degree indicates that the development height of hydraulic fracture zone in research area is disturbed by aquifer actual disturbance; Risk assessment results indicate that high risk of water inrush lies in southwest side of research area and prevention should be strengthened when mining. This study provides a new idea for evaluating risk zoning of coal seam roof gushing (inrush) water in coal mines of Binchang.

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