scholarly journals Damage Characteristics and Mechanism of a 2010 Disastrous Groundwater Inrush Occurred at the Luotuoshan Coalmine in Wuhai, Inner Mongolia, China

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 655 ◽  
Author(s):  
Fangpeng Cui ◽  
Qiang Wu ◽  
Chen Xiong ◽  
Xiang Chen ◽  
Fanlan Meng ◽  
...  
Keyword(s):  
Coal Seam ◽  
Inner Mongolia ◽  
In Situ Stress ◽  
Economic Losses ◽  
Karst Collapse ◽  
Great Effort ◽  
Groundwater Inrush ◽  
Collapse Column ◽  
Great Damage

On 1 March 2010, a disastrous groundwater inrush occurred at the Luotuoshan coalmine in Wuhai (Inner Mongolia, China). Great effort was taken during the post-accident rescue. However, triggered by a large amount of groundwater rushed in from the Ordovician limestone aquifer underlying the No.16 coal seam through the fractured sandy claystone and the karst collapse column, it caused great damage, including 32 deaths and direct economic losses of over 48 million yuan. The groundwater inrush originated from the floor heave in the air return gallery of the No.16 coal seam. The peak inflow rate was 60,036 m3/h. The gallery excavation under conditions caused by the incompletely recognized hydrogeological environment induced the accident. The unidentified spatial distribution of the karst collapse column triggered the accident directly. The high-pressure groundwater accumulated in the collapse column and the gallery excavation, which caused the redistribution of the in situ stress, contributing to progressive fractures in the floor of the No. 16 coal seam. Eventually, an intensive water-conductive passage consisting of the fractured floor and the karst collapse column formed. Administratively/technically, that mandatory regulations on gallery excavation were not carried out which contributed the accident. Moreover, the poor awareness about groundwater inrush recognition and quick remediation also contoirbuted to the disastrous extent of the accident.

scholarly journals Damage Characteristics and Mechanism of a Strong Water Inrush Disaster at the Wangjialing Coal Mine, Shanxi Province, China

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Cui Fangpeng ◽  
Wu Qiang ◽  
Zhang Shuai ◽  
Wu Ningan ◽  
Ji Yuan
Keyword(s):  
Coal Mine ◽  
Water Inrush ◽  
Groundwater Exploration ◽  
Shanxi Province ◽  
Economic Losses ◽  
Great Effort ◽  
Groundwater Inrush ◽  
Mining Face ◽  
Inrush Water ◽  
Great Damage

A serious groundwater inrush occurred at the Wangjialing coal mine on March 28, 2010. Great effort from all over the country was taken during the postaccident rescue. However, triggered by accumulated water in the upper abandoned tunnels and goafs of a nearby closed individually owned coal mine, it caused great damage, including 38 deaths and direct economic losses of over 49 million yuan. The inrush water was from the abandoned tunnels and goafs, which were filled subsequently by groundwater from the sandstone aquifer in the roof of the coal seam. The passage formed in the west roof of the heading face of the air return tunnel in the 20101 first mining face. Unidentified distribution and water-filled degree of the abandoned tunnels and goafs are critical bases for the accident. That important regulations for abundant groundwater exploration and release were not carried out thoroughly was another fatal cause leading to the accident. The poor awareness of water hazard controlling also contributed to the accident to a large extent.

scholarly journals Characteristics of in situ stress and its influence on coal seam permeability in the Liupanshui Coalfield, Western Guizhou

2021 ◽  
Author(s):  
Xiaojie Fang ◽  
Caifang Wu ◽  
Xiuming Jiang ◽  
Ningning Liu ◽  
Dan Zhou ◽  
...  
Keyword(s):  
Coal Seam ◽  
In Situ Stress ◽  
Western Guizhou

Estimation of the present-day stress field using in-situ stress measurements in the Alxa area, Inner Mongolia for China's HLW disposal

2017 ◽  
Vol 220 ◽  
pp. 76-84 ◽  
Author(s):  
Jianju Du ◽  
Xianghui Qin ◽  
Qingli Zeng ◽  
Luqing Zhang ◽  
Qunce Chen ◽  
...  
Keyword(s):  
Stress Field ◽  
Inner Mongolia ◽  
In Situ Stress ◽  
Stress Measurements ◽  
In Situ Stress Measurements

scholarly journals Study of the influencing factors of the liquid CO2 phase change fracturing effect in coal seams

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254996
Author(s):  
Jinzhang Jia ◽  
Dongming Wang ◽  
Bin Li ◽  
Xiuyuan Tian
Keyword(s):  
Coal Seam ◽  
Phase Change ◽  
Peak Pressure ◽  
In Situ Stress ◽  
Simulation Software ◽  
Hole Diameter ◽  
Gas Pressure ◽  
Physical Parameters ◽  
Simulation Results

To study the influence of different factors on the cracking effect of the liquid CO2 phase transition, the mechanics of coal rock crack extension based on liquid CO2 phase change blast loading were studied. Through the application of simulation software to analyze the influence of coal seam physical parameters (in situ stress, gas pressure, modulus of elasticity and strength of coal) and blasting parameters (fracturing pore size and peak pressure of detonation)on the effect of liquid CO2 phase change cracking, the simulation results showed that the cracking effect of liquid CO2 phase change was positively correlated with the changes in gas pressure, elastic modulus, fracture hole diameter and peak vent pressure, negatively correlated with the variation in situ stress and compressive strength, and nearly independent of the tensile strength. In addition, by using Gray correlation analysis to analyze the influence degree of six main factors on the cracking effect, the calculation results showed that the effect of blasting parameters was greater than that of physical parameters. The main controlling factor that affected the blasting effect was the peak pressure of blasting release. By conducting comparative engineering trials with different blasting parameters, the test results showed that the crack effect of the coal seam was positively correlated with the change in fracture hole diameter and peak venting pressure, which was consistent with the results obtained from the simulation. The experimental results and simulation results for the effective radius of coal seam fracturing were basically consistent, with the error between the two types of results falling below 10%. Therefore, the reliability of the blasting numerical model was verified. In summary, the research results provide theoretical guidance for applying and promoting liquid CO2 fracturing technology in coal mines.

scholarly journals Prediction of Fracture Evolution and Groundwater Inrush from Karst Collapse Pillars in Coal Seam Floors: A Micromechanics-Based Stress-Seepage-Damage Coupled Modeling Approach

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Yinlong Lu ◽  
Bingzhen Wu ◽  
Mengqi He ◽  
Lianguo Wang ◽  
Dan Ma ◽  
...  
Keyword(s):  
Coal Seam ◽  
Karst Collapse ◽  
Hydraulic Pressure ◽  
Groundwater Inrush ◽  
Modeling Approach ◽  
Fracture Evolution ◽  
Damage And Fracture ◽  
Working Face ◽  
Prediction And Prevention ◽  
Gradual Process

Karst collapse pillars (KCPs) frequently cause severe groundwater inrush disasters in coal mining above a confined aquifer. An accurate understanding of the damage and fracture evolution, permeability enhancement, and seepage changes in KCPs under the combined action of mining-induced stress and confined hydraulic pressure is of great significance for the early prediction and prevention of groundwater inrush from KCPs in coal seam floors. In this study, a micromechanics-based coupled stress-seepage-damage (SSD) modeling approach, in which the macroscopic mechanical and hydraulic properties of the rock are explicitly related to the microcrack kinetics, is proposed to simulate the fracture evolution and the associated groundwater flow in KCPs. An in situ high-precision microseismic monitoring technology is used to verify the micromechanical modeling results, which indicate that the numerical model successfully reproduces the damage and fracture evolution in a coal seam floor with a KCP during the mining process. The presented model also provides a visual representation of the complex process of KCP activation and groundwater inrush channel formation. A numerical study shows that the damage and activation of a KCP start from the edge of the KCP, gradually develop toward the interior of the KCP, and eventually connect with the damage fracture zone of the floor, forming a primary water-conducting channel in the KCP, causing the confined groundwater to flow into the working face. Groundwater inrush from a KCP is a gradual process instead of a mutation process. A reduction in the distance between the working face and a KCP and increases in the confined hydraulic pressure and the initial water-conducting height of the KCP can significantly increase the risk of groundwater inrush from the KCP.

scholarly journals Modeling Rock Fracture Propagation and Water Inrush Mechanisms in Underground Coal Mine

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Shichuan Zhang ◽  
Baotang Shen ◽  
Yangyang Li ◽  
Shengfan Zhou
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Rock Fracture ◽  
Water Inrush ◽  
Water Channel ◽  
Karst Collapse ◽  
Mining Equipment ◽  
Geological Conditions ◽  
Fracturing Process ◽  
Collapse Column

Water inrush in underground mines is a major safety threat for mining personnel, and it can also cause major damage to mining equipment and result in severe production losses. Water inrush can be attributed to the coalescence of rock fractures and the formation of water channel in rock mass due to the interaction of fractures, hydraulic flow, and stress field. Hence, predicting the fracturing process is the key for investigating the water inrush mechanisms for safe mining. A new coupling method is designed in FRACOD to investigate the mechanisms of water inrush disaster (known as “Luotuoshan accident”) which occurred in China in 2010 in which 32 people died. In order to investigate the evolution processes and mechanisms of water inrush accident in Luotuoshan coal mine, this study applies the recently developed fracture-hydraulic (F-H) flow coupling function to FRACOD and focuses on the rock fracturing processes in a karst collapse column which is a geologically altered zone linking several rock strata vertically formed by the long-term dissolution of the flowing groundwater. The numerical simulation of water inrush is conducted based on the actual geological conditions of Luotuoshan mining area, and various materials with actual geological characteristics were used to simulate the rocks surrounding the coal seam. The influences of several key factors, such as in situ stresses, fractures on the formation, and development of water inrush channels, are investigated. The results indicate that the water inrush source is the Ordovician limestone aquifer, which is connected by the karst collapse column to No. 16 coal seam; the fracturing zone that led to a water inrush occurs in front of the roadway excavation face where new fractures coalesced with the main fractured zone in the karst collapse column.

scholarly journals Study on Temporal and Spatial Characteristics of Overlying Strata in Deep Coal Mining Process

2021 ◽  
Author(s):  
Bang-an Zhang ◽  
Yang yushun ◽  
Dong-ming Zhang
Keyword(s):  
Stress Concentration ◽  
Coal Seam ◽  
Coal Mining ◽  
Three Dimensional ◽  
In Situ Stress ◽  
Three Dimensional Model ◽  
Concentration Coefficient ◽  
Working Face ◽  
Stress Concentration Coefficient

Abstract This paper adopts the stress relief method to test the in-situ stress in the field to obtain the in-situ stress distribution characteristics of No. 2+3# coal seam. A three-dimensional model was established with the No. S3012 working face as the engineering background, and the measured in-situ stress values ​​were applied to the three-dimensional model, and the spatial-temporal evolution characteristics of coal and rock mass around the stope during coal seam mining were studied. The specific conclusions are as follows: the three-dimensional stress distribution map in front of, behind and on both sides of the working face in the process of coal mining are obtained. As the working face goes on, the maximum value of the supporting stress formed in front of, behind and on both sides of the working face shifts to the corner, presenting a “hump-like” distribution. The stress concentration coefficient of front, back and both sides of stope increases linearly with the increase of mining size. Under the same mining size, the stress concentration coefficient in front of stope is the smallest, and the stress concentration coefficient on both sides is the largest. The three-dimensional displacement field distribution nephogram of overlying strata in the process of coal mining is obtained. With the continuous advance of the working face, the roof strata of coal seam undergo continuous dynamic subsidence process, and the roof subsidence increases continuously, showing the shape of "bowl" with sharp bottom. In the process of working face mining, the roof displacement of coal seam showed an "O" shape evolution characteristic. The three-dimensional distribution cloud map of the plastic zone of coal and rock mass in the process of working face mining was obtained, and the failure volume of the plastic zone gradually increases with the continuous progress of the working face.

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