scholarly journals The Effects of Backfill Mining on Strata Movement Rule and Water Inrush: A Case Study

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 66 ◽  
Author(s):  
Jian Hao ◽  
Yongkui Shi ◽  
Jiahui Lin ◽  
Xin Wang ◽  
Hongchun Xia
Keyword(s):  
Longwall Mining ◽  
Water Inrush ◽  
Vertical Stress ◽  
Strata Movement ◽  
Ground Pressure ◽  
In Situ Investigation ◽  
Floor Failure ◽  
Backfill Mining ◽  
Failure Depth

Backfill mining is widely used to control strata movement and improve the stress environment in China’s coal mines. In the present study, the effects of backfill mining on strata movement and water inrush were studied based on a case study conducted in Caozhuang Coal Mine. The in-situ investigation measured abutment pressure distribution (APD), roof floor displacement (RFD), and vertical stress in the backfill area. Results are as follows: (i) The range and peak of APD, RFD, and vertical stress in the backfill area are smaller than in traditional longwall mining with the caving method. (ii) Backfill mining could change the movement form and amplitude of overburden and improve the ground pressure environment. (iii) Floor failure depth (FFD) is much smaller in backfill mining. Backfill mining can be an effective method for floor water inrush prevention.

scholarly journals Voussoir beam model for lower strong roof strata movement in longwall mining – Case study

2017 ◽  
Vol 9 (6) ◽  
pp. 1171-1176 ◽  
Author(s):  
Chuang Liu ◽  
Huamin Li ◽  
Hani Mitri ◽  
Dongjie Jiang ◽  
Huigui Li ◽  
...  
Keyword(s):  
Longwall Mining ◽  
Beam Model ◽  
Strata Movement ◽  
Roof Strata

Analysis of floor failure depth by using electric profiling method in longwall gangue backfill mining

2013 ◽  
Vol 19 (3) ◽  
pp. 282-289 ◽  
Author(s):  
Sheng-Li Yang ◽  
Xin-Pin Ding ◽  
Xin Wang ◽  
Xiao-Meng Li ◽  
Li Lin
Keyword(s):  
Floor Failure ◽  
Backfill Mining ◽  
Failure Depth ◽  
Electric Profiling

On-Site Monitoring of Floor Failure Depth with High Confined Water and Mining Risk Assessment

2013 ◽  
Vol 716 ◽  
pp. 693-698
Author(s):  
Shu Xin Liu ◽  
Chang Wu Liu ◽  
Ya Ming Kang ◽  
Duo Yang
Keyword(s):  
Water Inrush ◽  
Ground Subsidence ◽  
Confined Water ◽  
Mining Technology ◽  
Working Face ◽  
Site Monitoring ◽  
Floor Failure ◽  
Depth Analysis ◽  
Face Length ◽  
Failure Depth

About under-group coal seams mining with the threat of high-pressure ordovician water, conventional mining technology by draining depressurization usually causes environmental issues such as soil erosion and ground subsidence etc.,By using grouting reinforcement technology, this paper changes floor direct charge layer into relatively separatedwater layer in the coal seam and achieves the goals of sealing the water inrush channel, moreover, on the basis of coal floor failure depth analysis and monitoring, the paper evaluates risk of water-inrush from seam floor when face length increases, On this basis, puts forward a reasonable working face length and mining technology, and has abtained good economic and social benefits in practice.

scholarly journals Floor Failure Evolution Mechanism for a Fully Mechanized Longwall Mining Face above a Confined Aquifer

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Jinghui Zhai ◽  
Danlong Liu ◽  
Gang Li ◽  
Fangtian Wang
Keyword(s):  
Longwall Mining ◽  
Water Inrush ◽  
Friction Angle ◽  
Peak Position ◽  
Depth Range ◽  
Confined Aquifer ◽  
Factors Affecting ◽  
Floor Failure ◽  
Failure Evolution ◽  
Pressure Stress

In longwall mining, the risk of water inrushes from the floors of deeply buried coal seams is closely related to the degree and depth of the destruction for the mining floor. To analyze the main factors affecting floor failure and the evolution of such failures, this study considered the LW2703 working face of the Chengjiao Coal Mine in China, which is characterized by a large buried depth, complex fault structure, and high pressure from a confined aquifer. The characteristics affecting floor crack development depth were analyzed by considering friction angle, cohesion force, floor pressure, stress increase coefficient, and peak position. A FLAC3D simulation was performed to compare the degrees of floor damage that occurred for caving and backfilling methods during the mining process. High-density electrical detection was performed on-site and used to (1) determine the maximum depth range of the floor damage, (2) reveal the laws governing the evolution of damage in a mining floor, and (3) provide a reasonable basis for evaluating and preventing floor water inrush accidents.

scholarly journals Investigation on Failure Characteristics of Coal Seam Floor in Paste Filling Working Face

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qingliang Chang ◽  
Xingjie Yao ◽  
Chongliang Yuan ◽  
Qiang Leng ◽  
Hao Wu
Keyword(s):  
Theoretical Model ◽  
Coal Seam ◽  
Water Inrush ◽  
Failure Behavior ◽  
Term Strength ◽  
Failure Characteristics ◽  
Working Face ◽  
Floor Failure ◽  
Failure Depth

Water inrush disasters are extremely prone to occur if the coal seam floor contains a confined aquifer. To find out the failure behavior of coal seam floor of paste filling working face, a beam-based theoretical model for the floor aquifuge was built, and then, the water inrush risk was evaluated based on the thickness of floor aquifuge. Next, the floor failure characteristics of the paste filling face was numerically studied and the effects of the filling interval and long-term strength of the filling body on the floor failure depth, stress and displacement distributions, and plastic zone were explored. The results showed that the theoretical model for evaluating the safety of the floor of the paste filling face based on the empty roof distance is proved to be consistent with that of the empirical formula judged based on the assumption that the paste filling working face was regarded as a cut hole with a certain width. The filling interval has a significant effect on the stress concentration of the surrounding rock, failure depth of floor, and roof-floor convergence. The smaller the filling interval is, the smaller their values are. When the filling rate is 98%, the long-term strength of the filling body is 5 MPa, and the floor failure depth is not more than 4 m. In contrast, the strength of the filling body has no obvious influence on the floor failure depth, but it has a certain impact on the roof-floor convergence. From the perspective of reducing floor failure depth, there is no need to increase the long-term strength of backfill, but it is necessary to increase the early strength of backfill so as to reduce the width of the equivalent roadway.

scholarly journals Control of Water Inrush from Longwall Floor Aquifers Using a Division Paste Backfilling Method

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Qingliang Chang ◽  
Xingjie Yao ◽  
Shiguo Ge ◽  
Ying Xu ◽  
Yuantian Sun
Keyword(s):  
Water Inrush ◽  
Water Injection ◽  
Field Measurements ◽  
Mining Method ◽  
Confined Water ◽  
Working Face ◽  
Floor Failure ◽  
Site Water ◽  
Failure Depth ◽  
Theoretical Analyses

Aiming at the problem of the safety mining problems of longwall paste filling working face under buildings on high confined water in the Daizhuang Coal Mine, the paste filling mining method was used. A series of theoretical analyses, numerical simulations, and field measurements were applied. The results showed that when the filling interval of the working face increases from 1.2 m to 3.6 m, no significant change is found in the depth of the perforated plastic zone of the floor strata. According to the types of water-conducting cracks in the floor strata of the working face 11607, the floor strata are divided into the floor intact area, the structure developed area, and the floor weak area. Based on that, the measures for preventing and controlling the floor failure in the paste filling working face are proposed. Furthermore, the failure depth of the floor of the test working face was detected by the on-site water injection method, and the results showed that the maximum failure depth of the floor of the test working face was about 3 m.

Floor Destruction Characteristic Study of Confined Water Effected by Mining Conditions

2012 ◽  
Vol 619 ◽  
pp. 253-258
Author(s):  
Lu Bin He ◽  
Bo Hou
Keyword(s):  
Water Inrush ◽  
Arbitrary Point ◽  
Base Plate ◽  
Horizontal Stress ◽  
Bottom Plate ◽  
The Sun ◽  
Confined Water ◽  
Infinite Body ◽  
Floor Failure ◽  
Failure Depth

Combined with Huaibei Mining Group 1028 Face of the Sun Tong mine site conditions,elasticity in the plane semi-infinite body established by the base plate of a mechanical model in the triangle strip load was used. The bottom plate of arbitrary point in the state of stress was analysised,and calculation formula of the horizontal stress,vertical stress and shear stress.was deduced.Based on elastic-plastic theory for solving the floor failure depth calculation of the floor limit conflict, the size of the water inrush combined with the Sun Tong mine 10 coal aquifer water inrush stress was analysised.The results of theoretical analysis of this article has some guidance, for the site management of the Sun Tong mine and has some reference for similar conditions.

scholarly journals Mechanical Analysis of the Failure Characteristics of Stope Floor Induced by Mining and Confined Aquifer

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhiguo Lu ◽  
Wenjun Ju ◽  
Xiwen Yin ◽  
Zhuoyue Sun ◽  
Fengda Zhang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Stress Gradient ◽  
Absolute Error ◽  
Horizontal Stress ◽  
Vertical Stress ◽  
Confined Aquifer ◽  
Solid Coal ◽  
Floor Failure ◽  
Failure Depth

Mining above confined aquifer has become an important task for water inrush prevention in China. To study the failure characteristics of stope floor along the strike, a mechanical model under combined action of mining and confined aquifer was constructed, and the distribution of vertical stress, horizontal stress, and shear stress was obtained. Based on the Mohr–Coulomb criterion, the failure range of the floor is determined and verified by the in situ test. The results indicate the following. (1) Both vertical stress and horizontal stress in the stope floor take the junction of stress increasing area and stress decreasing area as the dividing line, forming two groups of “convex arches” at the solid coal side and the goaf side, respectively. (2) The vertical stress gradient in the solid coal side is significantly higher than that in the goaf side, while the horizontal stress gradient in the solid coal side is similar to that in the goaf side. The shear stress distribution is divided into three regions by the boundary between positive and negative shear stress, which makes the stope floor in this area to show compression shear or tension shear failure. (3) According to the in situ test, the maximum floor failure depth of 41503 working face is 11.38 m, which is quite close to the theoretical calculation result of 9.68 m. (4) Applying the mechanical model to five other coal mines with different mining conditions and stress states, the maximum absolute error between the measured and theoretical values of floor failure depth is 1.1 m, the average absolute error is 0.8 m, the maximum relative error is 8.2%, and the average relative error is 6.5%. The study provides a certain mechanical basis and reference for the floor failure mechanism induced by mining and confined aquifer.

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