scholarly journals Risk assessment of Cretaceous water inrush in the Ordos Basin based on the FAHP-EM

Water Policy ◽  
2021 ◽  
Author(s):  
Tingen Zhu ◽  
Wenping Li ◽  
Weichi Chen
Keyword(s):  
Risk Assessment ◽  
Coal Seam ◽  
Ordos Basin ◽  
Water Inrush ◽  
Entropy Method ◽  
Western China ◽  
Analytic Hierarchy ◽  
Water Head ◽  
The Ordos Basin ◽  
Seam Mining

Abstract A study on the risk of Cretaceous water inrush in the Ordos Basin in China is of great significance to the safe production and environmental protection of the western coal seam. This paper selects the following five key influencing factors for Cretaceous water inrush: the coal seam mining thickness, rock quality designation, distance between the top boundary of the water-conducting fracture zone and the bottom boundary of the Cretaceous system, the thickness of the Cretaceous aquifer, and the height of the water head. Furthermore, based on an analysis of geological and hydrogeological conditions of the Yingpanhao coal mine, the comprehensive weights of these factors were found using a fuzzy analytic hierarchy process and the entropy method (FAHP-EM) to be 0.27, 0.25, 0.22, 0.08, and 0.18, respectively. This paper describes the use of ArcGIS's spatial overlay analysis to create a risk assessment zoning map using these weightings. By comparing the evaluation results of the FAHP-EM and the water inrush coefficient method, it is shown that the FAHP-EM provides additional insight in assessing the risk of coal seam roof water inrush. The research results of this paper provide a theoretical basis for coal mining safety in western China to assess water inrush.

An approach for water-inrush risk assessment of deep coal seam mining: a case study in Xinlongzhuang coal mine

2020 ◽  
Vol 27 (34) ◽  
pp. 43163-43176
Author(s):  
Qixiong Gu ◽  
Zhen Huang ◽  
Shijie Li ◽  
Wei Zeng ◽  
Yun Wu ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Coal Seam ◽  
Coal Mine ◽  
Water Inrush ◽  
Seam Mining

scholarly journals A Mechanical Model of the Overlying Rock Masses in Undersea Coal Mining and a Stress-Seepage Coupling Numerical Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Jie Fang ◽  
Lei Tian ◽  
Yanyan Cai ◽  
Zhiguo Cao ◽  
Jinhao Wen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Coal Mining ◽  
Water Inrush ◽  
Mining Area ◽  
Analysis Model ◽  
Fractured Zones ◽  
Working Face ◽  
Seam Mining ◽  
Overlying Strata

The water inrush of a working face is the main hidden danger to the safe mining of underwater coal seams. It is known that the development of water-flowing fractured zones in overlying strata is the basic path which causes water inrushes in working faces. In the engineering background of the underwater mining in the Longkou Mining Area, the analysis model and judgment method of crack propagation were created on the basis of the Mohr–Coulomb criterion. Fish language was used to couple the extension model into the FLAC3d software, in order to simulate the mining process of the underwater coal seam, as well as to analyze the initiation evolutionary characteristics and seepage laws of the fractured zones in the overlying strata during the advancing processes of the working face. The results showed that, during the coal seam mining process, the mining fractured zones which had been caused by the compression-shear and tension-shear were mainly concentrated in the overlying strata of the working face. Also, the open-off cut and mining working face were the key sections of the water inrush in the rock mass. The condition of the water disaster was the formation of a water inrush channel. The possible water inrush channels in underwater coal mining are mainly composed of water-flowing fractured zones which are formed during the excavation processes. The numerical simulation results were validated through the practical engineering of field observations on the height of water-flowing fractured zone, which displayed a favorable adaptability.

scholarly journals Testing a Comprehensive Volcanic Risk Assessment of Tenerife by Volcanic Hazard Simulations and Social Vulnerability Analysis

2020 ◽  
Vol 9 (4) ◽  
pp. 273 ◽  
Author(s):  
Weiqiang Liu ◽  
Long Li ◽  
Longqian Chen ◽  
Mingxin Wen ◽  
Jia Wang ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Risk Reduction ◽  
Social Vulnerability ◽  
Volcanic Hazards ◽  
Entropy Method ◽  
Volcanic Risk ◽  
Analytic Hierarchy ◽  
The North ◽  
Volcanic Risk Assessment ◽  
The Impact

Volcanic activity remains highly detrimental to populations, property and activities in the range of its products. In order to reduce the impact of volcanic processes and products, it is critically important to conduct comprehensive volcanic risk assessments on volcanically active areas. This study tests a volcanic risk assessment methodology based on numerical simulations of volcanic hazards and quantitative analysis of social vulnerability in the Spanish island of Tenerife, a well-known tourist destination. We first simulated the most likely volcanic hazards in the two eruptive scenarios using the Volcanic Risk Information System (VORIS) tool and then evaluated the vulnerability using a total of 19 socio-economic indicators within the Vulnerability Scoping Diagram (VSD) framework by combining the analytic hierarchy process (AHP) and the entropy method. Our results show good agreement with previous assessments. In two eruptive scenarios, the north and northwest of the island were more exposed to volcanic hazards, and the east registered the highest vulnerability. Overall, the northern municipalities showed the highest volcanic risk in two scenarios. Our test indicates that disaster risk varies greatly across the island, and that risk reduction strategies should be prioritized on the north areas. While refinements to the model will produce more accurate results, the outputs will still be beneficial to the local authorities when designing policies for volcanic risk reduction policies in Tenerife. This study tests a comprehensive volcanic risk assessment for Tenerife, but it also provides a framework that is applicable to other regions threatened by volcanic hazards.

scholarly journals Discussion on Advanced Seepage Reduction Characteristics of Working Face under Seepage-Damage Coupling

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Feisheng Feng ◽  
Jiqiang Zhang ◽  
Zhen Yang ◽  
Dongdong Pang ◽  
Jing Zhang
Keyword(s):  
Stress Field ◽  
Coal Seam ◽  
Water Inrush ◽  
Seepage Flow ◽  
Mechanics Model ◽  
Working Face ◽  
Management Modes ◽  
Reduction Characteristics ◽  
Seam Mining ◽  
Two Sectors

The water burst of roof on working face has been one of the significant geotechnical engineering problems that needs to be urgently resolved. The coupling effects of seepage and damage on the amount and intensity of water inrush from the roof are critically important. In this paper, the seepage-damage coupling mathematical model of the aquifer in the working face is studied, and the seepage-damage coupling mechanics model at different stages of the aquifer is established. Under the coupling of permeability and damage, the water-soil characteristics of the aquifer in the 101163 working face of Mindong were numerically simulated by establishing the constitutive relation between vertical stress and permeability coefficient. The numerical results show that the stress concentration factor of the mining stress field gradually increases with the coal seam mining. The water-flowing fractured zone of the overburden is close to the communication of the quaternary aquifer. When the coal seam is excavated 250–300 m. Three free surfaces appear in the groundwater pressure field, and a large falling funnel is formed to establish a deep flow S-well well flow model. The research on the mining stress field and seepage field is carried out in combination with the Jakob formula. It is found that two sectors with reduced permeability of the fan surface are formed in front of the work. The variation law of the apocalyptic permeability infiltration under different mining distances, different coal seam thicknesses, different water pressures, and different roof management modes is studied systematically. The research indicates that the seepage flow under the condition of seepage infiltration of the lower aquifer should be between 50% and 100% of the traditional calculation method. The research results can help to deepen the understanding of the process of water inrush under the coupling of stress and seepage.

scholarly journals Numerical study of the influence of coal seam mining under reservoir on deep oversize fault deformation

2019 ◽  
Vol 23 (4) ◽  
pp. 2315-2322
Author(s):  
Xinxian Zhai ◽  
Yanwei Zhai ◽  
Xingzi Tu ◽  
Rubo Li ◽  
Guangshuai Huang
Keyword(s):  
Coal Seam ◽  
Numerical Study ◽  
Hanging Wall ◽  
Water Inrush ◽  
Coal Pillar ◽  
Simulation Software ◽  
Face Advance ◽  
Pillar Width ◽  
Coal Face ◽  
Seam Mining

Ground surface in Yonglong coal mine is hilly terrain. There is a Yinshigou reservoir on minefield. Deep coal seam mining under the reservoir has an influence on the deformation of oversize normal fault, and can cause severe mine water-inrush. Using numerical simulation software UDEC, the paper studied the characteristics of plastic zone and stress field in front of coal face in the hanging wall of the fault, while the coal face advance distances from setting-up room to coal face line were different. The results showed that while the distance from coal face to the fault i. e. the width of fault-protected pillar, was 80 m, the front abutment pressure had less influence on two sides rock mass of the fault, the fault reduced the vertical stress of its surrounding rocks; The surrounding rocks in the vicinity of fault were in a same vertical displacement contour, whose displacement was very smaller. Reasonable fault-protected pillar width of the numerical study was much closer to the average water-proof coal pillar width based on coal mines water prevention regulations of China. Consequently, while the width of fault-protected pillar is more than 80 m, coal seam mining in hanging wall of fault has no influence on the fault, and coal seam safely mining under the reservoir could be carried out.

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.

Study on Coal Seam Mining Face Floor Failure under Imbalance High Water Pressure

2014 ◽  
Vol 919-921 ◽  
pp. 758-761 ◽  
Author(s):  
Chun Jie Song ◽  
Cheng Fan ◽  
Li Song
Keyword(s):  
Coal Seam ◽  
Water Pressure ◽  
Water Inrush ◽  
Simulation Software ◽  
Pressurized Water ◽  
Coal Deformation ◽  
Floor Failure ◽  
Mining Face ◽  
Seam Mining ◽  
Fluidstructure Interaction

According to the seam floor aquifer inhomogeneity,in order to analysis the coal deformation and failure law in pressurized water ,this paper established mechanical model of nonuniform pressure and fluidstructure interaction models,using numerical simulation software FLAC3D analysis fluidstructure interaction water inrush regularity .Analyzing the extent of damage from the coal seam floor, the stress and displacement when working face promote different distances, this paper carried out the basic rules of mining face water inrush. This study shows that by monitoring the position of bottom water inrush occurs easily, analyzing the influence of pore pressure by the mining ,it can be accurately analysis the risk of water inrush and play an important role in guiding prevention and control of water inrush.

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