scholarly journals Prediction and Treatment of Water Leakage Risk Caused by the Dynamic Evolution of Ground Fissures in Gully Terrain

2022 ◽  
Vol 9 ◽  
Author(s):  
Dong Feng ◽  
Enke Hou ◽  
Xiaoshen Xie ◽  
Xiaoyang Che ◽  
Pengfei Hou ◽  
...  
Keyword(s):  
Coal Seam ◽  
Mine Drainage ◽  
Dynamic Evolution ◽  
Burial Depth ◽  
Test Model ◽  
Ground Fissure ◽  
Treatment Methods ◽  
Ground Fissures ◽  
Groundwater Leakage ◽  
Seam Mining

Groundwater leakage in the loess gully terrain is one of the main hazards of coal seam mining at shallow burial depth. The burial depth of the 5−2 coal seam is less than 50 m from the ground in the gully of the study site. The fissures that expand upward after mining can easily penetrate the ground to form a water-conducting channels. During rainy periods, there is a potential risk of groundwater leakage. In order to reveal the characteristics of plane development and the dynamic evolution of gully ground fissures, the typical U-shaped gully in the northern Shaanxi coal mine was studied using the field measurement methods of “On-site measurement” and UAV aerial photography. Based on the experimental platform of ground fissure leakage developed and designed by the team, an indoor test model corresponding to the actual situation was established. In addition, the mathematical models of actual flood inrush, fissure width, and flood flow in the channel were established. The actual mine water flow and the mine drainage capacity were compared and analyzed, thus proposing criteria for classifying gully mining ground fissure collapsed water hazards. These criteria can provide theoretical references for predicting fissure leakage hazard zones in the ground gully of shallow buried coal seams. According to the development height of the water-conducting fissure zone (WCFZ), the treatment methods of ground fissures in gullies under different security conditions were designed, which was applied in the field with good results. The results showed that the treatment methods in this paper could effectively prevent the leakage of groundwater in the gullies along the ground fissures.

scholarly journals Method to Calculate Mining-Induced Fracture Based on the Movement and Deformation of Overburden Strata

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Guo-sheng Xu ◽  
Hui-gui Li ◽  
De-hai Li ◽  
Yan-bin Zhang
Keyword(s):  
Coal Seam ◽  
Burial Depth ◽  
Empirical Methods ◽  
Fractured Zone ◽  
Strata Movement ◽  
Probability Integral Method ◽  
Movement And Deformation ◽  
Probability Integral ◽  
Seam Mining ◽  
Overburden Strata

Mining-induced fracture of overburden strata is intimately related to underground water disasters in coal mining. In this work, we develop an analytical model that uses the probability integral method to calculate the subsidence of the subsurface and the overburden strata. In the developed model, according to the failure characteristics of the mining-induced strata, the horizontal deformation of the strata is expressed by the tensile rate of the elastic plate’s neutral plane to reflect the degree of fracture initiation and expansion. The distribution of the water-flowing fractured zone (WFZ) in the overburden strata is calculated by substituting the probability integral function of overburden strata movement into the equation of layer tensile rate. The panel 31071 in Peigou coal mine is taken as a case study, and the height of the water-flowing fractured zone (HWFZ) is determined by the proposed method. Conventional empirical methods and the proposed method are used to predict HWFZ in panels with mining schemes, and the results show that the model is particularly advantageous for inclined coal seam mining where the inclined mining size gradually increases and the coal seam burial depth gradually decreases. In such kind of situations, the overburden strata movement and deformation intensify and the mining fracture develops further with the progress of mining, a feature considered poorly by conventional empirical methods but well represented in the proposed method.

scholarly journals Influencing Factors’ Analysis of Disturbance Degree of Key Stratum Based on the Response Surface Method

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yang Li ◽  
Nan Wang ◽  
Yuqi Ren ◽  
Xiangji Ou ◽  
Yikun Liu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Response Surface ◽  
Response Surface Method ◽  
Interlayer Spacing ◽  
Burial Depth ◽  
Key Stratum ◽  
Surface Method ◽  
Calculation Results ◽  
Seam Mining ◽  
Mining Height

The key stratum controls the activities of the overlying strata or the whole strata up to the surface, which is one of the important research objects in the coal seam mining. Based on the analysis of several geological factors affecting on the key stratum, the definition of “disturbance degree of key stratum” (KSDD) was proposed. And, the KSDD is quantified by the value among 0 to 10. Through the response surface method, experiments of three factors (mining height, buried depth, and interlayer spacing) with three different lithology types (soft, medium, and hard) between key stratum and coal seam are signed. And, the KSDD of each scheme is calculated by the developed calculation system. The response surface regression models of KSDD with three lithology types are established. And, the single influence and interactive influences of the three factors on the KSDD with different lithology types are studied. The results show that the following. (1) Mining height and buried depth are positively correlated with the value of KSDD, and the interlayer spacing is negatively correlated with KSDD. However, when the value of interlayer spacing exceeds 30 m, the change of the KSDD tends to be gentle. (2) The value of KSDD is not only affected by a single factor but also affected by the interaction of various factors. With the increase of burial depth, the decrease of interlayer spacing and the impact of mining height on key stratum are more severe. (3) The influence order of each factor on KSDD is as follows: the interlayer spacing > mining height > buried depth. (4) Although the three factors interact with each other, the three factors decrease with the increase of the lithology proportional coefficient. According to the above research results, based on the calculation results of KSDD on five mines, the variation laws of KSDD with actual situation are analysed. And, the calculation results further verify the above experimental rules, which provide a certain reference and theoretical basis for the design of backfilling parameters and the management of the roof.

scholarly journals Quantitative Evaluation for the Threat Degree of a Thermal Reservoir to Deep Coal Mining

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yun Chen ◽  
Xinyi Wang ◽  
Yanqi Zhao ◽  
Haolin Shi ◽  
Xiaoman Liu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Fuzzy Variable ◽  
Thermal Storage ◽  
Burial Depth ◽  
Eastern Region ◽  
Analytic Hierarchy ◽  
Water Abundance ◽  
Total Study Area ◽  
Seam Mining

Taking the Suiqi coalfield located in North China as the object, where the coal seam burial depth is more than 1100 m, the water abundance of the roof pore thermal storage aquifer is better than average, the ground temperature is abnormally high, and hydrogeological data are relatively lacking, this paper selects and determines eight index factors that influence the mining of the coalfield. Based on the analytic hierarchy process (AHP), the index factor weight is defined, and then, the threat degree of the roof thermal storage aquifer to the coal mining is quantitatively evaluated and divided by using the fuzzy variable set theory. The evaluation results show that the threat degree of the roof in the eastern region is generally greater than that in the western region and that the closer it is to the coal seam outcrop line, the higher the threat degree is; near the boreholes, in the areas Qs1,Qs5, Qs8, Sx1, Tk5, Zc4, and Zc7, which are close to the hidden outcrop line of the coal seam, the classification characteristic value of the threat degree is greater than 3.5, which is in the high-threat zone for disasters caused by roof thermal storage aquifers during coal seam mining. The area above the medium-threat zone accounts for 71.82% of the total study area, indicating that deep coal mining is affected by multiple factors and that roof water and heat disasters are more likely to occur.

Study on the Dynamic Development of Ground Fissures in Shallow Coal Seam Mining Under Ditch

2021 ◽  
Author(s):  
zheng cheng
Keyword(s):  
Coal Seam ◽  
Strain Analysis ◽  
Similar Material ◽  
Ground Fissures ◽  
Dynamic Development ◽  
Working Face ◽  
Shallow Coal Seam ◽  
Northern Shaanxi ◽  
The Right ◽  
Seam Mining

Abstract Abstract In order to study the dynamic evolution law of ground fissures in shallow coal seam mining under ditch，taking the 14210 working face of a mine in northern Shaanxi as an example, this paper analyzes the dynamic development law of ground fissures in the process of mining under ditch through similar material simulation combined with the VIC-3D monitoring system. The results show that there are 20 ground fissures in the 14210 working face. The development width of ground fissures increases first, then decreases rapidly, and finally closes at the bottom of the ditch. The ground uplifts with a height of 1.5 m. The development width of ground fissures increases first, then decreases slightly, and finally tends to stabilize on the left and the right slopes, resulting in staggered steps with a height of 1.6 m and 0.7 m respectively. This change process is consistent with that of the strain of the underlying overburden obtained by VIC-3D strain analysis. According to their development positions and strain changes, the ground fissures are divided into three categories: tensile ground fissures on the left slope T1-T8, squeeze ground fissures at the bottom of the ditch T9-T13, and tensile ground fissures on the right slope T14-T20. Finally the safety analysis of mining under ditch in the 14210 working face is carried out.

Water inflow characteristics of coal seam mining aquifer in Yushen mining area, China

2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Zhao Chunhu ◽  
Jin Dewu ◽  
Wang Qiangmin ◽  
Wang Hao ◽  
Li Zhixue ◽  
...  
Keyword(s):  
Coal Seam ◽  
Mining Area ◽  
Water Inflow ◽  
Seam Mining

Mechanical model for the calculation of stress distribution on fault surface during the underground coal seam mining

2021 ◽  
Vol 144 ◽  
pp. 104765
Author(s):  
Hongwei Wang ◽  
Ruiming Shi ◽  
Jiaqi Song ◽  
Zheng Tian ◽  
Daixin Deng ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Coal Seam ◽  
Mechanical Model ◽  
Fault Surface ◽  
Seam Mining

Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Geological Conditions ◽  
Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

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