scholarly journals Geological Structure Exploration of Karst Collapse Column and Evaluation of Water Insulation Properties of the Mud Part

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Shijian Yu ◽  
Jiyang Liu ◽  
Peng Bai ◽  
Hongtao Xu ◽  
Runshan He ◽  
...  
Keyword(s):  
Water Inrush ◽  
Splitting Method ◽  
Geological Structure ◽  
Karst Collapse ◽  
Electrical Characteristics ◽  
X Ray Diffraction ◽  
Working Face ◽  
Mineral Compositions ◽  
Collapse Column ◽  
Brazilian Splitting

In this study, the X5 KCC in Shiquan Coal Mine was investigated by means of controlled source audio magnetotelluric exploration and borehole television. In this way, the subsection geological structure of the KCC was obtained. Next, the geological and electrical characteristics of each part were analyzed, and it is concluded that the development status of the mud part under coal seam floor is the key part to judging whether water inrush will occur during working face recovery under aquifer pressure. Furthermore, the mineral compositions of purplish-red mudstone and lime mudstone were obtained by performing an X-ray diffraction experiment on the KCC interstitial materials. On this basis, the water insulation properties of the mud part were qualitatively evaluated. Finally, the tensile strength of the mud part was obtained by the Brazilian splitting method, and the water insulation ability of the mud part at the periods when the tunneling roadway and the working face passed the KCC was calculated, respectively. The research results boast guiding significance for safe recovery of the working face passing KCCs under aquifer pressure.

scholarly journals Evolution Mechanism of Water-Conducting Channel of Collapse Column in Karst Mining Area of Southwest China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhengzheng Cao ◽  
Yulou Ren ◽  
Qinting Wang ◽  
Banghua Yao ◽  
Xinchao Zhang
Keyword(s):  
Coal Seam ◽  
Southwest China ◽  
Water Inrush ◽  
Mining Area ◽  
Karst Collapse ◽  
Coal Field ◽  
Conducting Channel ◽  
Evolution Mechanism ◽  
Working Face ◽  
Collapse Column

There are many karst collapse columns in coal seam roof in the southern coal field in China, which are different from those in coal seam floor in the northern coal field, due to the stratum characteristics. The karst collapse column in coal seam roof tends to reactivate and conduct water and induce the serious water inrush disaster, when the karst collapse column communicates with the overlying aquifer. In order to reveal the evolution mechanism of water-conducting channel of collapse column in karst mining area of southwest China, the aquifers and water inflow rule in 1908 working face in Qianjin coal mine are analyzed. Besides, the particle size distribution and mineral component of collapse column are researched by the X-ray diffraction test and the screening method, which are the basis for researching the water inrush mechanism in karst collapse column. On this basis, the water inrush of roof collapse column under the influence of mining is researched by establishing the numerical calculation model with the UDEC numerical software. The results show that the water flowing into the 1908 working face comes from the Changxing formation aquifer and Yulongshan formation aquifer above the coal seam, and the proportion of coarse particles and fine particles in collapse column is 89.86% and 10.14%, respectively. With the advance of working face, the water-conducting channel connected the working face with the aquifer, or the surface is formed by collapse pits, karst caves, and collapse column. The research results can be treated as an important basis for the water-preserved mining in southern coal field in China.

scholarly journals A non-linear flow model for the flow behavior of water inrush induced by the karst collapse column

RSC Advances ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 1656-1665 ◽  
Author(s):  
Xian'gang Hou ◽  
Wenhao Shi ◽  
Tianhong Yang
Keyword(s):  
Flow Model ◽  
Flow Behavior ◽  
Water Inrush ◽  
Karst Collapse ◽  
Flow Transition ◽  
Linear Flow ◽  
Non Linear ◽  
Collapse Column

A non-linear flow model that couples three flow types is built based on flow transition to investigate the flow behavior of water inrush induced by KCC.

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 Seepage Property of Crushed Mudstone Rock in Collapse Column

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Bo-Yang Zhang ◽  
Zhi-Bin Lin
Keyword(s):  
Particle Size ◽  
Water Resource ◽  
Water Inrush ◽  
Underground Water ◽  
Economic Losses ◽  
Karst Collapse ◽  
Hydraulic Pressure ◽  
Water Flow Velocity ◽  
Collapse Column ◽  
Seepage Properties

The karst collapse column composed of crushed rocks and fine argillaceous or clay particles is easy to form the fissure channels between the coal seam working face and the confined limestone aquifer under mining and causes water inrush disasters with the loss of underground water resource, economic losses, and casualties. It is of great necessity to understand the seepage properties of crushed rock in karst collapse column for the prevention of water inrush and the protection of underground water resource. A self-developed seepage test system is used in this paper to conduct laboratory experiments on seepage properties of crushed mudstone specimens. The effects of the particle size distribution, the porosity (specimen height), and the hydraulic pressure on the water flow velocity and the permeability of crushed specimen are analyzed. The results indicate that the permeability of specimen increases with the particle size, porosity, and hydraulic pressure. It can be known from the comparative experiments of progressive hydraulic pressure on one specimen and variable hydraulic pressure on different specimens with constant particle size and porosity that more fine particles leak out from the specimen with repeated application of hydraulic pressure on one specimen. Therefore, the permeability of one specimen is bigger than that of different specimens under the condition of same hydraulic pressure.

scholarly journals Analysis and Application of the Mechanical Properties of the Karst Collapse Column Fillings

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Zhibin Lin ◽  
Boyang Zhang ◽  
Xiaofei Gong ◽  
Limin Sun ◽  
Wenzhen Wang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Moisture Content ◽  
Water Inrush ◽  
Friction Angle ◽  
Karst Collapse ◽  
Filling Material ◽  
Cohesive Stress ◽  
Consolidation Pressure ◽  
Collapse Column

The filling material of the karst collapse column (KCC) is easy to be activated by mining. During this process, the mechanical properties of KCC fillings change, and its water resisting capacity constantly deteriorates and thus often leads to water inrush disaster. In this study, the samples of KCC fillings were taken on-site and then were remolded by the consolidation drainage method. The variation laws of the compressive strength, tensile strength, cohesive stress, internal friction angle, and permeability of the filling samples with respect to the consolidation pressure and moisture content were tested and analyzed. Based on an engineering example, the yield and activation and particle loss of the filling material of the KCC are analyzed. A mechanism for the lagging water inrush of KCC in the process of mining is proposed. The main results of the present study can be concluded concisely as follows. (1) The KCC fillings show obvious soft rock characteristics in the process of uniaxial compression and Brazilian split. The ratio of the uniaxial compressive strength to splitting tensile strength is between 12 : 1 and 8 : 1. The larger the consolidation pressure or the smaller the moisture content, the larger the ratio. (2) With the increase of consolidation pressure or the decrease of moisture content, the uniaxial compressive strength, elastic modulus, splitting tensile strength, cohesive stress, and internal friction angle of the filling material of the KCC increase linearly, while its permeability increases exponentially. (3) When the crack field of the surrounding rocks of the stope is connected with the KCC, its filling material will continue to yield, activate, and migrate under the fluid-solid coupling effect and finally result in the lagging water inrush from the KCC.

scholarly journals Research on Characteristic Recognition and Dangerous Prevention While Mining through Collapse Column of Pansan Minefield,China

2021 ◽  
Author(s):  
Haitao Xu ◽  
hui yang ◽  
Wenbin Sun ◽  
Lingjun Kong ◽  
Peng Zhang
Keyword(s):  
Coal Seam ◽  
Water Inrush ◽  
Coal Pillar ◽  
Simulation Software ◽  
Coal Seams ◽  
Transient Electromagnetic ◽  
Working Face ◽  
Electromagnetic Detection ◽  
Floor Failure ◽  
Collapse Column

Abstract In order to find out the characteristics of geological isomer exposed in the mining process of 12318 working face in Pansan Mine and grasp its influence law on subsequent coal seams mining, the isomer was firstly determined as the collapse column by means of 3D seismic, transient electromagnetic detection, SYT detection and other methods, and its development characteristics, conductivity and water enrichment were identified.Then FLAC3D numerical simulation software was used to analyze the characteristics of vertical stress and plastic failure zone in different coal seams during mining.Finally, by comparing the ultimate failure depth of floor and the thickness of waterproof layer in the process of each coal seam directly pushing through the collapse column, the risk of water inrush and the prevention are analyzed.The results show that the exposed geological isomer is characterized by weak water-rich collapse column.Under the influence of the mining of the previous coal seam and the activation of the collapse column, the subsequent coal seam is in the low stress area before mining, which increases the floor failure and causes the activation of the collapse column more easily during mining.Coal 5# and 4# can be directly pushed through the collapse column, and coal pillar of sufficient width should be left for coal 1# to prevent the collapse column from activating water inrush.

The Analysis of the Coal Floor Water Inrush Effected by the Fault

2014 ◽  
Vol 535 ◽  
pp. 626-630
Author(s):  
Yun Xun Zhang ◽  
She Rong Hu ◽  
Ji Chao Peng ◽  
Xue Qing Zhang
Keyword(s):  
Water Pressure ◽  
Water Inrush ◽  
Bottom Layer ◽  
Geological Structure ◽  
Mine Pressure ◽  
Confined Water ◽  
Working Face ◽  
The Face ◽  
Pressure Water ◽  
Floor Water Inrush

Water inrush from coal floor is some kind of complex geology and mining phenomenon. It is the confined water underlying the coal seams breaking the barrier of the bottom layer, and the water runs into the face of mine in emergencies or delayed, causing natural disasters like discharge increases or flooding. According to the previous studies on water inrush, the water inrush is a joint result of geological structure, water pressure, mine pressure, water-resisting floor and mining of working face. The thesis focuses on the influence of geological fault on the water-inrush from coal floor and analyses the controlling effects of fault property and non-water conducted fault activation of water in order to provide a reference or significance for the analysis of water-inrushs genesis mechanism.

A method for prevent water inrush from karst collapse column: a case study from Sima mine, China

2017 ◽  
Vol 76 (14) ◽  
Author(s):  
Hao Li ◽  
Haibo Bai ◽  
Jianjun Wu ◽  
Huiming Zhao ◽  
Kai Ma
Keyword(s):  
Water Inrush ◽  
Karst Collapse ◽  
Collapse Column

scholarly journals Comprehensive Exploration and three-dimensional construction technology of water plug based on directional horizontal drilling caved column

2021 ◽  
Vol 237 ◽  
pp. 03003
Author(s):  
Gan Tian
Keyword(s):  
Water Inrush ◽  
Three Dimensional ◽  
Comprehensive Treatment ◽  
Filling Material ◽  
Distribution Characteristics ◽  
Horizontal Drilling ◽  
3D Geological Modeling ◽  
Working Face ◽  
Fracture Area ◽  
Collapse Column

The ordovician limestone water inrush accident occurred during the excavation of 8228 working face in Tashan Coal Mine, Tongmei Group. On the basis of comprehensive geophysical exploration above and below the well, in order to find out the development boundary of the water flowing subsided column and the distribution characteristics of the broken body filled in it, and to control the subsided column by Grouting, the development boundary, the influence zone, the cementation of the fractured body and the distribution characteristics of the water flowing subsided column are found out by means of multi-layer and multi-branch surface directional horizontal drilling speed logging, drilling fluid leakage, cuttings logging and logging while drilling, and combined with data statistical analysis. The length and short axis of the collapse column is 410m - 200m, and the broken area is mainly distributed in the right front of the driving head of the belt roadway near the water inrush roadway. The 3d geological modeling of the spatial structure and development characteristics of the collapse column is carried out by using SURPAC software, and the main passageway area, fracture area and secondary fracture area are divided according to the crushing degree of the collapse column filling material. In view of the different zones of the collapse column broken body, the directional horizontal drilling control technology and the three-dimensional block grouting technology are used to construct the separate zones of the grouting technology. The safe mining of the working face is finally realized by the comprehensive treatment of cutting the source and reinforcing the water-flowing collapse column. The comprehensive exploration and treatment technology of directional horizontal drilling multi-branch collapse column provides a good reference for other similar projects.

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