Numerical simulation on pressure-relief deformation characteristics of underlying coal-rock mass after upper protective layer excavation

2013 ◽  
Vol 19 (3) ◽  
pp. 276-281 ◽  
Author(s):  
Jian Liu ◽  
Jie Zhao ◽  
Ming-Song Gao
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Protective Layer ◽  
Deformation Characteristics ◽  
Pressure Relief ◽  
Coal Rock

Study on Underlying Coal and Strata Pressure-Relief Principle and the Gas Extraction Technique under Upper Protective Layer Mining

2014 ◽  
Vol 875-877 ◽  
pp. 1863-1870 ◽  
Author(s):  
Jian Liu ◽  
Jie Zhao ◽  
Ming Song Gao
Keyword(s):  
Rock Mass ◽  
Coal Seam ◽  
Protective Layer ◽  
Extraction Technique ◽  
Efficient Production ◽  
Gas Extraction ◽  
Pressure Relief ◽  
Fracture Development ◽  
Floor Heave ◽  
Coal Rock

By study on underlying coal and strata pressure-relief principle and the gas extraction technique under upper protective layer mining, we obtain the stress change and distribution law of underlying coal-rock mass. We analyze the deformation law and fracture development characteristics of underlying coal-rock mass movement. With mining proceeding ahead, the total floor coal and rock experiences compression deformation first, then expansion deformation and re-compaction of the continuous periodic destruction. Based on different development characteristics and status of underlying coal-rock mass, the underlying coal-rock mass under an effect of upper protective layer mining was divided into the floor heave fracture zone and the floor heave deformation zone in this paper. The permeability coefficient of change law of underlying the coal seam as follows: the original value-small decreasing-increasing greatly-reducing-stability at last. The field test for upper protective layer mining of Zhang-ji coal mine of Huainan shows that the effect of pressure relief of protected seam is very good. So it eliminates the risk of gas outburst, ensuring safety mining of the protected seam. The research has an important significance for safety and efficient production under similar exploitation conditions of low-permeability with high gas and outburst risk coal seam.

scholarly journals Mining-Induced Pressure-Relief Mechanism of Coal-Rock Mass for Different Protective Layer Mining Modes

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xiang Cheng ◽  
Guangming Zhao ◽  
Yingming Li ◽  
Xiangrui Meng ◽  
Qingyi Tu ◽  
...  
Keyword(s):  
Rock Mass ◽  
Coal Seam ◽  
Volume Expansion ◽  
Axial Stress ◽  
Soft Rock ◽  
Protective Layer ◽  
Confining Pressure ◽  
Mining Area ◽  
Pressure Relief ◽  
Coal Rock

The protective layer mining method of the traditional deep coal seam in has been confronted with great challenges, and it is difficult for coal and gas to be extracted together. Taking the occurrence conditions of III1 mining area of Luling Coal Mine located at Huaibei, China, as engineering background, the influence law of the lithology on stress environment in front of the stope was analyzed by theoretical analysis and numerical simulations. The mining-induced mechanical effect of coal-rock mass was studied under different protective layer mining modes. The results showed that the peak value of the advanced abutment pressure decreased with the decrease of lithologic strength under the same mining conditions. For simulated geological conditions, the stress concentration coefficient of soft rock and coal seam protective layer mining modes was 1.9 and 1.7, respectively. Under the mining stress path of different protective layers, the ratio of axial stress increase and confining pressure unloading in secondary unloading phase were 2 : 1 and 1.5 : 1, respectively. The axial stress-strain curves of different protective layer mining modes had similar trends, and they had a volume expansion at the end of unloading (failure stage). In addition, it revealed the pressure-relief antireflection mechanism of the protective layer mining. Under the same confining pressure condition, the peak stress and peak strain increased with the increase of loading and unloading velocity ratio. The reduced value of the confining pressure increased, while the volume expansion decreased at failure. The results were applied to III1 mining area in soft rock protective layer mining, which created the mining way of traditional coal seam protective layer. Furthermore, the gas control technology of soft rock protective layer working face was put forward for deep coal seam with low permeability and high gas, enriching the pressure-relief mining theory of protective layer.

Study on Pressure Relief Scope of Underlying Coal Rock with Upper Protective Layer Mining

2013 ◽  
Vol 734-737 ◽  
pp. 661-665
Author(s):  
Ben Qing Yuan ◽  
Yong Jiang Zhang ◽  
Jian Jun Cao ◽  
Guo Jian Cheng
Keyword(s):  
Theoretical Analysis ◽  
Protective Layer ◽  
Calculation Model ◽  
Infinite Plane ◽  
Pressure Relief ◽  
Discrimination Criterion ◽  
Coal Rock ◽  
Elastic Mechanics ◽  
The Impact ◽  
Scope Of Protection

In this paper,in the case of upper protective layer mining of a mine for the engineering background, based on the model of semi-infinite plane body in elastic mechanics, the theoretical calculation model of verticalhorizontalshear stress of floor coal rock is established, and it is concluded that the stress expression of any point in the impact of distributed force. By introducing the rock strength index I and generalized Hooke's law, it is concluded that the discrimination criterion of guide gas fissure zone and pressure relief desorption belt of underlying coal rock with upper protective layer mining. The pressure relief scope of protection with the mining of upper protective layer is determined. Theoretical analysis shows that: the "pressure relief desorption zone" of the underlying protected coal seam that the vertical distance to the protective layer is 40m lags behind 22.2m.Through field test, the results show that the obtained pressure relief scope of protection is 26.98m,and the theoretical analysis results are basically similar.

scholarly journals Solid-Gas Coupling Model for Coal-Rock Mass Deformation and Pressure Relief Gas Flow in Protection Layer Mining

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Zhuohui Zhu ◽  
Tao Feng ◽  
Zhigang Yuan ◽  
Donghai Xie ◽  
Wei Chen
Keyword(s):  
Rock Mass ◽  
Gas Flow ◽  
Coupling Model ◽  
Pressure Relief ◽  
Coal Rock ◽  
Rock Mass Deformation ◽  
Protection Layer ◽  
Mining Coal ◽  
Migration Law ◽  
Mass Deformation

The solid-gas coupling model for mining coal-rock mass deformation and pressure relief gas flow in protection layer mining is the key to determine deformation of coal-rock mass and migration law of pressure relief gas of protection layer mining in outburst coal seams. Based on the physical coupling process between coal-rock mass deformation and pressure-relief gas migration, the coupling variable of mining coal-rock mass, a part of governing equations of gas seepage field and deformation field in mining coal-rock mass, is introduced. Then, a new solid-gas coupling mathematical model reflecting the coupling effects of gas adsorption/desorption, gas pressure, and coal-rock mass deformation on the mining coal-rock mass deformation and pressure relief gas flow is established combined with the corresponding definite conditions. It lays a theoretical foundation for the numerical calculation of the deformation of mining coal-rock mass and the migration law of gas under pressure relief in the outburst coal seam group.

The Surrounding Rock of Deep Borehole Pressure Relief and Let the Pressure Bolt Coupling Analysis

2013 ◽  
Vol 446-447 ◽  
pp. 1421-1424 ◽  
Author(s):  
Shu Guang Zhang ◽  
Long Chen ◽  
Hong Yu Jia
Keyword(s):  
Numerical Simulation ◽  
High Stress ◽  
High Strength ◽  
Surrounding Rock ◽  
Deformation Characteristics ◽  
Deep Borehole ◽  
Pressure Relief ◽  
High Strength Bolt ◽  
Supporting Effect ◽  
Coupling Support

Roadway borehole pressure relief and let the pressure anchor combined support technology were based on using the new pressure high strength bolt instead of ordinary bolt ,Combined with the borehole pressure relief principle, aim at releasing high stress of surrounding rock of roadway ,Complying with the deformation characteristics of supporting technology of the surrounding rock. In this paper, we used scaled numerical simulation technology —— ADINA to analyze the roadway borehole pressure relief and let the pressure anchor coupling support technology. To the tunnel, we used the method of numerical simulation of let the pressure bolt support independently, drilling pressure relief, and borehole pressure relief and let the pressure anchor coupling support three kinds of the comparison numerical simulation. The advantages of coupling supporting effect was elaborated, It was instructive for the deeply roadway engineering in the future.

Numerical Simulation Study on the Stress - Deformation Characteristics of Rock Mass of Luding Power Transmission Project in Sichuan

2013 ◽  
Vol 368-370 ◽  
pp. 1688-1692
Author(s):  
Lei Wang ◽  
Yu Sheng Li ◽  
Qing Song Huang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Rock Mass ◽  
Simulation Study ◽  
Power Transmission ◽  
Deformation Characteristics ◽  
Horizontal Shear ◽  
Stress Deformation ◽  
Finite Element Numerical Simulation ◽  
Project Site

In this page, combination of finite element numerical simulation and discrete element numerical simulation is used to study the stress - deformation characteristics of rock mass of power transmission project site,whichclarifies the rock mass stress is mainly controlled by thegravitational field,the form of the potential deformationis dominated by compression deformation,andthere is no possibility of occurrence of the horizontal shear deformation.

Numerical Simulation of Damage and Deformation Characteristics of Rock Mass with Transfixion Joint

2013 ◽  
Vol 405-408 ◽  
pp. 369-372
Author(s):  
Lei Wang ◽  
Jiang Yu ◽  
Jian Xin Han
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Strain Curve ◽  
Simulation Method ◽  
Joint Surface ◽  
Deformation Characteristics ◽  
Stress Strain Curve ◽  
Deformation Parameters ◽  
Strength And Deformation ◽  
Set Up

Use FLAC3D, the interface command to define joint surface, set up rock mass models with 15 °, 30 °, 60 °, etc. different dip joint, and in accordance with the laboratory test data of rock and joint surface for a variety of strength and deformation parameters setting, carries on the numerical simulation of uniaxial compression. Got failure mode, plastic zone evolution and the stress strain curve of rock mass with different dip joint, and the result compared with the actual test has a higher similarity, to prove the feasibility of the numerical simulation method.

scholarly journals Analysis of the Influence of Upper Protective Layer Mining on the Effect of Pressure Relief and Protection of Coal and Rock Masses between the Lower Overburden Layers

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Jiaxin Dang ◽  
Min Tu ◽  
Xiangyang Zhang ◽  
Qingwei Bu
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Expansion Ratio ◽  
Pressure Relief ◽  
Protection Effect ◽  
Protective Seam ◽  
Coal Wall ◽  
Seam Mining ◽  
Protective Seam Mining ◽  
Relief Effect

Protective seam mining is an effective gas pressure relief method in deep mining. Effective theoretical calculation methods in the current studies on the prediction of pressure relief protection effect of interbed coal and rock masses and their distribution laws are lacking. Thus, the evaluation and research with respect to pressure relief effect in protective seam mining relatively lag behind. This situation restricts the engineering feasibility evaluation and decision making in the protective seam mining. Therefore, the influence of upper protective seam mining on the pressure relief protection effect of coal and rock mass between underlying beds was investigated in this study. On the basis of an analysis of concrete engineering projects, a mechanical model was constructed for the pressure relief protection effect of upper protective seam mining on the coal and rock mass between underlying beds. The distribution equation of pressure relief expansion ratio in the underlying protected seam was also derived. The influence laws of main influencing factors on the pressure relief protection effect of the protected seam were revealed as well. In the end, the pressure relief effect was analyzed and verified for the protected seam before and after mining through numerical simulation and similarity simulation test. The pressure relief effect of upper protective seam mining on the coal and rock mass between underlying beds and the distribution characteristics were deeply explored in this study, which could provide a theoretical reference for the decision making in the gas extraction engineering design and pre-evaluation of extraction effect. Results show that the effective pressure relief zone (expansion rate>0.3%) of the protected seam beneath the goaf is located within the range of approximately 40 m from the coal wall to the rear part. It also presents an approximate “Λ-shaped distribution characteristic,” that is, it experiences migration and evolution with the advancement in the working face. Moreover, the peak pressure relief lags behind the coal wall on the working face by nearly 10–20 m. In the numerical simulation, the expansion ratio in the goaf also presents an approximate “Λ-shaped distribution.” Its effective pressure relief zone is the 50 m range from the coal wall to the rear part of the goaf, and the peak value lags behind the coal wall by around 15 m. The theoretical results and numerical simulation results are basically consistent with the physical experiment results. The expansion rates are 1.25%, 1.268%, and 1.32%, respectively. The elastic modulus E of coal seam and interbed spacing H are the main influencing factors of the swelling deformation and are negatively correlated with the expansion ratio. In the actual mining process, E and H of the protected layer can be measured to infer the expansion deformation of the protected layer.

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