scholarly journals Similar Physical Simulation on the Deformation of Surrounding Rocks of Floor Roadway Caused by Coal Mining Under Tectonic Stress

2017 ◽  
Vol 10 (2) ◽  
pp. 132-140 ◽  
Author(s):  
Zhongsi Dou ◽  
◽  
Jiwen Wu ◽  
Liang Wang ◽  
Xiaorong Zhai ◽  
...  
Keyword(s):  
Coal Mining ◽  
Physical Simulation ◽  
Tectonic Stress

scholarly journals Controlling Mechanism of Rock Burst by CO2 Fracturing Blasting Based on Rock Burst System

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Tianwei Lan ◽  
Chaojun Fan ◽  
Jun Han ◽  
Hongwei Zhang ◽  
Jiawei Sun
Keyword(s):  
Coal Mining ◽  
Rock Burst ◽  
Coal Mine ◽  
Prevention And Control ◽  
Stress Measurement ◽  
Tectonic Stress ◽  
Microseismic Monitoring ◽  
Time Space ◽  
Controlling Mechanism ◽  
And Control

Rock burst induced by mining is one of the most serious dynamic disasters in the process of coal mining. The mechanism of a rock burst is similar to that of a natural earthquake. It is difficult to accurately predict the “time, space, and strength” of rock burst, but the possibility of rock burst can be predicted based on the results of microseismic monitoring. In this paper, the rock burst system under the tectonic stress field is established based on the practice of coal mining and the result of mine ground crustal stress measurement. According to the magnitude of microseismic monitoring, the amount of the energy and spatial position of the rock burst are determined. Based on the theory of explosion mechanics, aiming at the prevention and control of rock burst in the coal mine, the technique of liquid CO2 fracturing blasting is put forward. By the experiment of blasting mechanics, the blasting parameters are determined, and the controlling mechanism of rock burst of liquid CO2 fracturing blasting is revealed. The application of liquid CO2 fissure blasting technology in the prevention and control of rock burst in Jixian Coal Mine shows that CO2 fracturing blasting reduces the stress concentration of the rock burst system and transfers energy to the deeper part, and there is no open fire in the blasting. It is a new, safe, and efficient method to prevent and control rock burst, which can be applied widely.

scholarly journals Large Deformation Mechanics of Gob-Side Roadway and Its Controlling Methods in Deep Coal Mining: A Case Study

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jianwei Zheng ◽  
Wenjun Ju ◽  
Xiaodong Sun ◽  
Zhongwei Li ◽  
Shuai Wang ◽  
...  
Keyword(s):  
Stress Field ◽  
Large Deformation ◽  
Coal Mining ◽  
Tectonic Stress ◽  
In Situ Stress ◽  
Field Analysis ◽  
Underground Mines ◽  
Roof Structure ◽  
Deformation Mechanics

Maintaining surrounding rock mass stability of roadways is essential to the safety of deep coal mining. In this study, the No. 2-2092 roadway of the No. 2-209 mining face in Ganhe coal was taken as the target roadway for field analysis. The selected region can be considered a typical area with dominating geological tectonic stress, based on the geological survey and in situ stress results. A mechanical model of roadway overburdens was developed to analyse the large deformation and stress field distribution. It is found that the large deformation is caused by the combined superposed stress field including laterally transferred stress formed in structures at overlying strata, mining-induced advanced abutment pressure, and the regional in situ stress. Thus, a Two-Direction Hydrofracturing Technique (TDHT) was proposed to reduce the pressure of the No. 2-2092 roadway by altering the roof structure in the influenced zones. Compared with the original roadway without fracturing, it is found that the roof to floor convergence has dropped by nearly 47% after fracturing; the displacement of sidewalls has reduced by almost 31%, demonstrating the effectiveness of the proposed method in pressure relief. Results from this study can provide guidance on controlling the large deformation of roadways in deep underground mines.

scholarly journals TESTING THE EFFECT OF UNDERMINING ON POSITIONAL ACCURACY OF THE DIGITAL TECHNICAL MAP OF OSTRAVA IN THE PŘÍVOZ CADASTRAL DISTRICT / PŘÍVOZ KADASTRINIO RAJONO ĮTAKOS OSTRAVOS SKAITMENINIO TECHNINIO ŽEMĖLAPIO POZICINIAM TIKSLUMUI PADARINIŲ TYRIMAS / АНАЛИЗ ВЛИЯНИЯ РАЗРУШАЮЩИХ СИЛ НА ПОЗИЦИОННУЮ ТОЧНОСТЬ ЦИФРОВОЙ ТЕХНИЧЕСКОЙ КАРТЫ Г. ОСТРАВА В КАДАСТРОВОМ РАЙОНЕ ПРИВОЗ

2011 ◽  
Vol 37 (3) ◽  
pp. 111-118
Author(s):  
Milan Mikoláš ◽  
Jiří Žváček ◽  
Michal Vaněk ◽  
Roman Donocik ◽  
Petra Zápalková ◽  
...  
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Coal Mining ◽  
Tectonic Stress ◽  
Surrounding Rock ◽  
Recent Past ◽  
Positional Accuracy ◽  
Landscape Morphology ◽  
The Town ◽  
Town Area

Intensive underground exploitation took place in the area of the Ostrava corporate town in recent past. After the coal mining was shut down in 1994 gradual subsidence in the town area has slowed down, however, establishing of the Digital Technical Map of Ostrava (DTMMO) dates back to 1992. When working a seam the original geostatic and tectonic stress state in the surrounding rock mass changes, which is accompanied by rock transformation and displacement from the roof towards the stope. Undermining is manifested in landscape morphology in many different ways that we can divide to continuous and discontinuous deformations. Residual mining effects could therefore have impacted positional accuracy of DTMMO in the last 18 years. The Bohumín 8-9/43 topographic sheet was selected for testing purposes in the Přívoz cadastral district. Santrauka Netolimoje praeityje Ostravos, miesto Čekijos rytuose, savivaldybėje buvo intensyviai eksploatuojama žemė. Nustojus užsiiminėti angliakasyba, nuo 1994-ųjų, palaipsnis žemės smukimas miesto vietovėse sulėtėjo. Skaitmeninis techninis Ostravos žemėlapis (DTMMO) sukurtas dar 1992 metais. Vykstant darbams žemės tarpsluoksnyje pirminis geostatinis ir tektoninis slėgis aplinkinėje uolienų masėje keitėsi, ir tai lėmė uolienų transformaciją ir slinktį. Kraštovaizdžio morfologijoje žala pasireiškia įvairiais būdais. Skiriama nenutrūkstamoji ir nutrūkstamoji deformacijos. Liekamasis kasybos poveikis per pstaruosius 18 metų galėjo paveikti pozicinį DTMMO tikslumą. Tiriant Přívoz kadastrinį rajoną, pasirinkta Bohumín 8-9/43 topografinio žemėlapio lapas. Резюме В недавнем прошлом в районе корпоративного г. Острава интенсивно эксплуатировались нижние слои грунта. После прекращения добычи угля в 1994 г. постепенное оседание поверхности города замедлилось. Созданная цифровая техническая карта г. Остравы (DTMMO) восходит к 1992 г. При работе с пластом возникающее исходное геостатическое и тектоническое возбуждение приводит к изменениям в окружающих пласт горных массивах, которые сопровождаются преобразованием пород и перемещениями в направлении забоя. Разрушение проявляется в морфологии ландшафта в самых разных формах, которые можно подразделить на непрерывные и разрывные деформации. Поэтому остаточные явления горных разработок могут оказывать влияние на позиционную точность DTMMO за последние 18 лет. Для анализа была выбрана топографическая плита Богумин 8-9/43 в кадастровом районе Привоз.

scholarly journals Seepage Law of Injected Water in the Coal Seam to Prevent Rock Burst Based on Coal and Rock System Energy

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Tianwei Lan ◽  
Chaojun Fan ◽  
Hongwei Zhang ◽  
A. S. Batugin ◽  
Luo Ruibin ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Rock Burst ◽  
Water Injection ◽  
Tectonic Stress ◽  
Energy Concentration ◽  
Engineering Practice ◽  
Principal Stresses ◽  
Rock System ◽  
The Law

Rock burst is one of the typical dynamic disasters in coal mining. In order to reveal the mechanism of rock burst from the energy view point, the relationships between the maximum, minimum, and intermediate principal stresses and the concentration coefficients of the gravity stress k1, k2, and k3 are determined through the geostress measurement combined with engineering practice of coal mining. The coal and rock system model based on the tectonic stress is established. The relationship between energy and scale radius of the coal and rock system is determined to reveal the law of energy accumulation, release, and transfer in the coal and rock system. In view of the characteristics of the porous medium in the coal seam, the measures of water injection are put forward to relieve pressure in the coal seam, and the law of water seepage in the process of water injection in the coal seam is studied based on the seepage mechanics. The result shows that the trend of released energy of damaged coal has good consistency with the variation of permeability, and water injection can reduce the stress concentration and energy concentration of the rock burst system. The engineering practice of the rock burst prevention was taken in Yuejin Coal Mine. The energy characteristics of the coal and rock system in the working face are analyzed, and the measures of water injection and the corresponding parameters are determined.

scholarly journals Physical simulation and theoretical evolution for ground fissures triggered by underground coal mining

PLoS ONE ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. e0192886 ◽  
Author(s):  
Jing-Hu Yang ◽  
Xiang Yu ◽  
Yi Yang ◽  
Zeng-Qiang Yang
Keyword(s):  
Coal Mining ◽  
Physical Simulation ◽  
Underground Coal Mining ◽  
Ground Fissures ◽  
Theoretical Evolution

Back Analysis of 3-D Initial Geostress of Laohutai Coal Mine by the Method of Multiple Regression and FLAC3D

2011 ◽  
Vol 66-68 ◽  
pp. 1617-1621
Author(s):  
Jian Jun Zhou ◽  
Tian Ya Zheng ◽  
Zhan Ling Fu ◽  
Lei Chen
Keyword(s):  
Coal Mining ◽  
Coal Mine ◽  
Back Analysis ◽  
Tectonic Stress ◽  
Test Results ◽  
In Situ Test ◽  
Theoretical Support ◽  
Regression Theory ◽  
Good Agreement

Initial geostress is one of the most important factors in coal mining. By combination the finite difference software FLAC3D with multivariate linear regression theory, 3-D initial geostress in situ is back analyzed, which also considers the effect of gravimetrical and tectonic stress. The back analysis results of initial geostress in Laohutai coal mine are in a good agreement with the in-situ test results, which provides theoretical support on prediction of geostress and also more convenient geostress data in coal mining.

scholarly journals Accurate Perception of Rock Strata Movement for Environmental Protection in Coal Mining: Taking Thick and Hard Roof Cooperative Control as an Example

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Tong Zhao ◽  
Changyou Liu ◽  
Kaan Yetilmezsoy ◽  
Majid Bahramian ◽  
Peilin Gong
Keyword(s):  
Environmental Protection ◽  
Coal Mining ◽  
Physical Simulation ◽  
Environmentally Friendly ◽  
Industrial Test ◽  
Confined Water ◽  
Hard Roof ◽  
Key Stratum ◽  
Accurate Perception ◽  
Rock Strata

Accurate perception of the key stratum instability can improve the safety of coal mining and also provide a basis for alleviating overlying rock strata destruction and environmental disturbance. To efficiently evaluate the instability of the key stratum and its threat to safe mining and environmental protection, the fracture characteristics and weakening mechanisms were studied through physical simulation, theoretical analysis, and field measurement. A scheme and the parameters of confined blasting in water-filled deep hole presplit technology (CBWDHPT) for thick and hard roof (THR) weakening were proposed. Research studies showed that, after the THR fractured into large blocks, the subsequent sliding instability induced serious support-crushing accidents; however, increasing the support strength could only provide limited control. Confined water and infiltrated modified rock mass functioned as the transfer load medium of the explosives, and the CBWDHPT fully utilized high explosion energy to break rocks. Consequently, the collapse and filling of the immediate roof and low-positioned THR, as well as the timely cutting off the middle-positioned THR, could be realized, which alleviated the migration space of THR blocks, overlying strata destruction, and earth-surface step subsidence. Finally, the environmentally friendly strategy (including the CBWDHPT and hydraulic support optimization) for overlying rock strata protection was proposed. In the industrial test, the THR was broken into blocks of different sizes after utilizing the CBWDHPT, and the support working resistance was significantly decreased. It was concluded that the environmentally friendly strategy could effectively reduce the risk of overlying rock strata destruction.

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