scholarly journals A New Quantitative Method for Risk Assessment of Coal Floor Water Inrush Based on PSR Theory and Extension Cloud Model

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Bingyou Jiang ◽  
Bo Ren ◽  
Mingqing Su ◽  
Bao Wang ◽  
Xin Li ◽  
...  
Keyword(s):  
Coal Seam ◽  
Cloud Model ◽  
Evaluation Model ◽  
Water Inrush ◽  
Indicator System ◽  
Working Face ◽  
Actual Evaluation ◽  
Evaluation Indicator System ◽  
Floor Water Inrush ◽  
Cloud Theory

In order to scientifically and reasonably assess the risk of water inrush from the coal seam floor, considering the influence of natural environmental factors such as hydrogeology, mining, and human intervention, the PSR model of ecosystem health evaluation was introduced, and the risk evaluation indicator system of water inrush from the coal seam floor was established. In order to solve the randomness and fuzziness of water inrush event evaluation, the evaluation model is constructed based on extension cloud theory and is applied in the 12123 working face of Pan Er coal mine of Huainan Mining Group. The application results show that the evaluation results are basically consistent with the actual situation, which shows that the model can be used in the actual evaluation work and is scientific.

Risk Evaluation of Water Inrush from Coal Floor Based on BP Neural Network

2015 ◽  
Vol 744-746 ◽  
pp. 1728-1732 ◽  
Author(s):  
Wei Tao Liu ◽  
Shi Liang Liu ◽  
Yan Shuang Sun
Keyword(s):  
Neural Network ◽  
Coal Seam ◽  
Bp Neural Network ◽  
Risk Evaluation ◽  
Evaluation System ◽  
Evaluation Method ◽  
Water Inrush ◽  
Test Collection ◽  
Working Face ◽  
Floor Water Inrush

According to the nonlinear dynamic characteristic of coal seam floor water inrush, coal seam floor water inrush risk evaluation which includes 4 first level indicators,14 level two indexes was built based BP neural network. According to the test collection of engineering data, coal seam floor water inrush risk evaluation system based VB and MATLAB is reliable. Application to a mine coal seam No.2 working face was verified. The results show that, the evaluation method in water inrush is feasible, reasonable.

scholarly journals Urban Stormwater Resilience Assessment Method Based on Cloud Model and TOPSIS

2021 ◽  
Vol 19 (1) ◽  
pp. 38
Author(s):  
Han Qiao ◽  
Jingjing Pei
Keyword(s):  
Cloud Model ◽  
Evaluation Model ◽  
Indicator System ◽  
Assessment Method ◽  
Ranking Method ◽  
Ideal Solution ◽  
Urban Resilience ◽  
Urban Stormwater ◽  
Evaluation Theory ◽  
Evaluation Indicator System

To scientifically and quantitatively evaluate the degree of urban storm resilience and improve the level of urban stormwater resilience, based on the resilience theory, starting from the three attributes of resilience (resistance, recovery and adaptability), this paper establishes the framework of urban resilience evaluation indicator system under the background of stormwater disaster. Firstly, the weight of the indicator system is analyzed by the Delphi method and cloud model, and then the urban stormwater recilience evaluation model is constructed by using the cloud model and approximate ideal solution ranking method. Through the fuzzy description, the corresponding quantitative value is given to the qualitative indicator, so that the stormwater resilience of the city can be measured by accurate values. Finally, the feasibility of the model is verified by case analysis. The results show that the urban stormwater resilience evaluation theory and method based on cloud model and approximate ideal solution ranking method have important guiding significance to improve the level of urban stormwater resilience.

scholarly journals Emergency Situation Safety Evaluation of Marine Ship Collision Accident Based on Extension Cloud Model

2021 ◽  
Vol 9 (12) ◽  
pp. 1370
Author(s):  
Yiyang Zou ◽  
Yingjun Zhang ◽  
Zhihong Ma
Keyword(s):  
Cloud Model ◽  
Evaluation Model ◽  
Safety Evaluation ◽  
Emergency Situation ◽  
Indicator System ◽  
Entropy Weight ◽  
Analytic Hierarchy ◽  
Entropy Weight Method ◽  
Evaluation Indicator System ◽  
Weight Method

After collisions at sea, situation evaluation and analysis are very important to follow-up rescue operations. At present, there are few ways give weights in the current situational safety evaluation methods after collisions of marine ships. Most safety evaluation models ignore the blurred boundaries of evaluation grades. To solve these issues, this paper identifies the safety evaluation indicator system and evaluation standards, and establishes an after-collisions safety evaluation model of maritime ships based on the extension cloud theory. This model combines the extension cloud model, the analytic hierarchy process, the entropy weight method, and game theory. Using this model, the situation safety of two collisions was evaluated. The evaluation results reflect the effectiveness of the model. In order to ensure the safety of the lives and property of marine personnel, suggestions have been made to strengthen crew training, improve ship’s self-rescue ability at sea, and establish a complete marine emergency response rescue system.

scholarly journals Exploration and application of directional long boreholes in coal measure strata

2021 ◽  
Vol 261 ◽  
pp. 03003
Author(s):  
Qin Ke ◽  
Peng Dong ◽  
Duan Huijun
Keyword(s):  
Coal Seam ◽  
Water Inrush ◽  
Critical Value ◽  
Coal Measure ◽  
Bottom Plate ◽  
Drain Water ◽  
Safe Water ◽  
Working Face ◽  
Water Hazard ◽  
Insulation Thickness

two roadways in adjacent working face of Baode Mine may have the risk of water inrush at the same time, so it is necessary to construct long borehole to cover the roadway excavation. On the basis of the hydrogeological conditions of the mine, the safe water insulation thickness and water inrush coefficient of coal seam No .8 are calculated. The results show that the water inrush coefficient is 0.035-0.037 MPa/m, which is less than the critical value 0.06 MPa/m and the bottom plate has no sudden water hazard. In the construction of No .10 coal seam, the directional long borehole is used to detect whether there is a hidden structure communicating with the floor limestone and to drain water. The test shows that there is no effluent phenomenon in the borehole, which proves that there is no hidden structure in No .10 coal seam.

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 Numerical Analysis of Stress Fields and Crack Growths in the Floor Strata of Coal Seam for Longwall Mining

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Lingzhi Sun ◽  
Yunyue Xie ◽  
Hongtian Xiao
Keyword(s):  
Coal Seam ◽  
Crack Growth ◽  
Water Pressure ◽  
Water Inrush ◽  
Coal Extraction ◽  
Additional Stress ◽  
Mining Activities ◽  
Confined Aquifer ◽  
Working Face ◽  
Distribution Features

This paper predicts the possibility of water inrush from a confined aquifer under the action of mining activities and water pressure. The study uses numerical analyses to evaluate stress redistribution and crack growth which result from coal extraction operations. Two models are presented in this study. By simplifying the distribution of the disturbed vertical stress on the coal seam and floor around a working face, a model is established to analyze the additional stresses in the floor strata induced by mining activities. And some distribution features of all the additional stress components are described. By using the superposition principle in fracture mechanics, another model is developed to analyze the crack growth in the floor strata under the action of disturbed stresses and water pressure. And the stress intensity factors at the crack tip are presented and the process of crack growth is obtained in the advancement of a working face. Because of discretizing only loading areas and crack surfaces, the present methods can obtain the accurate numerical results. Finally, some suggestions are made for preventing the water inrush from a confined aquifer.

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 Failure Characteristics and Confined Permeability of an Inclined Coal Seam Floor in Fluid-Solid Coupling

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jian Sun ◽  
Lianguo Wang ◽  
Guangming Zhao
Keyword(s):  
Stress Concentration ◽  
Coal Seam ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Inrush ◽  
Equivalent Stress ◽  
Confined Aquifer ◽  
Confined Water ◽  
Floor Water Inrush ◽  
Failure Depth

Secondary development of FLAC3D software was carried out based on FISH language, and a 3D fluid-solid coupling numerical calculation model was established for an inclined seam mining above a confined aquifer in Taoyuan Coal Mine. A simulation study was implemented on the mining failure depth of an inclined coal seam floor, conducting height of confined water, and the position of workface floor with easy water inrush during advancement of workface. Results indicated that, during the advancement of the inclined coal seam’s workface, obvious equivalent stress concentration areas existed in the floor strata, and the largest equivalent stress concentration area was located at the low region of workface floor. When the inclined coal seam workface advanced to about 80 m, the depth of floor plastic failure zone reached the maximum at approximately 15.0 m, and the maximum failure depth was located at the low region of the workface floor. Before the inclined workface mining, original confined water conducting existed on the top interface of the confined aquifer. The conducting height of the confined water reached the maximum at about 11.0 m when the workface was pushed forward from an open-off cut at about 80 m. Owing to the barrier effect of the “soft-hard-soft” compound water-resistant strata of the workface floor, pore water pressure and its seepage velocity in the floor strata were unchanged after the workface advanced to about 80 m. After the strata parameters at the workface floor were changed, pore water pressure of the confined water could pass through the lower region of the inclined workface floor strata and break through the barrier of the “soft-hard-soft” compound water-resistant strata of the workface floor and into the mining workface, resulting in the inclined coal seam floor water inrush. Results of this study can provide a basis for predicting, preventing, and governing the inclined coal seam floor water inrush above confined aquifer.

Condition Assessment of Regenerative Heater Based on Fuzzy Comprehensive Evaluation

2014 ◽  
Vol 687-691 ◽  
pp. 206-211
Author(s):  
Wei Dong Zheng ◽  
Pei Hong Wang
Keyword(s):  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Fuzzy Comprehensive Evaluation ◽  
Indicator System ◽  
Fuzzy Evaluation ◽  
Level Indicator ◽  
Comprehensive Evaluation Model ◽  
Evaluation Indicator System ◽  
Definition Of ◽  
Fuzzy Mathematic

In order to evaluate the performance of regenerative heater comprehensively and scientifically, the fuzzy comprehensive evaluation model of regenerative heater is proposed on the basis of fuzzy mathematic theory as well as the relevant background knowledge of the problem. In the fist-level fuzzy comprehensive evaluation model, the evaluation indicator system was established taking the influence of the turbine load into consideration. The definition of “excellence degree” was given to show the relative approach degree between the quantitative indicator and the excellent indicator. Membership functions of fuzzy evaluation set were constructed based on the excellence degree. Knowledge in terms of twenty experts’ experience and historical data was used to determine the indicator weight set. In the second-level indicator fuzzy comprehensive evaluation model, four composition operator models were selected to conduct the fist-level evaluation. The proposed model turns out to be feasible and effective by three typical load conditions.

Sign in / Sign up

Export Citation Format

Share Document