scholarly journals Stress Distribution and Failure Characteristics of Stope Overburden of an Inclined Coal Seam

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xin Liu ◽  
Jian Sun ◽  
Yong Yang
Keyword(s):  
Stress Distribution ◽  
Coal Seam ◽  
Shear Failure ◽  
Horizontal Displacement ◽  
Simulation Software ◽  
Fissure Zone ◽  
Failure Characteristics ◽  
Water Conduction ◽  
Caving Zone ◽  
Overlying Strata

The stress distribution, failure depth, and shape and range of overlying strata of the stope are important bases for the prevention of roof water hazards and determination of reasonable locations of roof roadways. Based on the hydrogeological data of the E9103 workface, FLAC numerical simulation software was used to establish a numerical calculation model of the overlying strata of the E9103 inclined coal seam, and the stress distribution and failure characteristics of the overlying strata were analyzed. The development height of the caving and water-flowing fractured zones in the overlying strata of the workface was determined. Results showed that the stress reduction area appeared above the goaf in the form of an “arched” distribution, and tensile stress occurred in the local area of the overburden. The overburden relief arch of the workface was symmetrically distributed along the advanced direction and asymmetrically distributed along the inclined direction, with the arch crown deflecting above the workface. The horizontal and vertical displacements of the overlying strata of the stope increased with the advancing distance of the workface. The horizontal displacement in the x -direction presented two obvious regions, and the critical points of the two regions moved forward with the advancement of the workface and showed a certain degree of symmetry. The horizontal displacement in the y -direction presented an “inverted bowl” distribution and increased with the advancement of the workface. The main failure forms of the overlying strata of the workface were a tensile and shear failure, and shear failure was dominant in the upper direction. The height of the overburden caving zone in the workface had little relationship with the advancing distance of the workface and increased slowly as the advancing distance of the workface increased. The development height of the caving zone is 7.2–18.13 m. The development height of the water conduction fissure zone increased rapidly with the increase in the advancing distance of the workface. When the advancing distance was equal to the length of the workface, the development height of the water conduction fissure zone was flat and basically maintained at a stable value. The development height of the water conduction fissure zone is 30.8–62.2 m. These research findings have important engineering importance for ensuring safe and efficient mining of E9103 workface.

Study on Mountainous Shallow-Buried Coal Seam Mining Working Face Strata Behaviors and Overlying Strata Movement Features

2011 ◽  
Vol 121-126 ◽  
pp. 2911-2916
Author(s):  
Guo Lei Liu ◽  
Ke Gong Fan ◽  
Tong Qiang Xiao
Keyword(s):  
Coal Seam ◽  
Horizontal Displacement ◽  
Simulation Software ◽  
High Rate ◽  
Strata Movement ◽  
Working Face ◽  
Element Simulation ◽  
Valve Opening ◽  
Seam Mining ◽  
Overlying Strata

Through testing the mountainous shallow-buried coal seam mining working face strata behaviors in Faer mine field, it got the strata behaviors: it was of large roof pressure, high rate of safety valve opening in hydraulic support, and even some supports crushed or took separation between top beams and tail beams. Traditional method of calculating supports’ resistance can not be applied to mountainous shallow-buried coal seam mining working face. With the discrete element simulation software UDEC it analyzed the strata movement feature, and got that the overlying strata took collapse and horizontal displacement after mountainous shallow-buried coal seam mined, and the strata movement feature was different between reverse slope mining and positive slope mining.

Research on Mining Technological Parameters of 7# Thin Coal Seam in Liuquan Mine

2012 ◽  
Vol 629 ◽  
pp. 937-942
Author(s):  
Dong Sheng Zhang ◽  
Xu Feng Wang ◽  
Yang Zhang ◽  
Jin Liang Wang
Keyword(s):  
Coal Seam ◽  
Distinct Element ◽  
Horizontal Displacement ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Technological Parameters ◽  
Thin Coal Seam ◽  
Geological Conditions ◽  
Universal Distinct Element Code ◽  
Distinct Element Code

Aimed at the specific geological conditions of 7# thin coal seam in Liuquan Mine, this paper used the methods of numerical calculation and theoretical analysis to determine the reasonable technological parameters of high-grade conventional mining face. The numerical simulation software of UDEC (Universal Distinct Element Code) was used to contrast and analyse the characteristics of surrounding rock stress distribution and overlying rock horizontal displacement under the condition of different length of coalface, then it was indicated that the surrounding rock deformation was less when length of coalface was 110 m which was advantageous for roof control; according to the conditions of roof and floor, the roof support strength was being calculated systematically to determine the row space of props being 700×1200 mm; the main equipments of coalface was assorted, and reasonable work manner in coalface and gob processing measure was put forward, which provided guidance for efficient mining in thin coal seam.

Analysis of Three-Dimensional Numerical Simulationin Rlue of the Migration Rule of Overlying Strata in Thick Seam Mining with Soft of Daping Mine

2013 ◽  
Vol 718-720 ◽  
pp. 1934-1937
Author(s):  
Meng Lin Xu ◽  
De Shen Zhao
Keyword(s):  
Theoretical Analysis ◽  
Coal Seam ◽  
Three Dimensional ◽  
Fissure Zone ◽  
Thick Coal Seam ◽  
Thick Seam ◽  
Soft Coal ◽  
Soft Coal Seam ◽  
Seam Mining ◽  
Overlying Strata

In order to delve better what research methodology of height of water conducted fissure zone are, especially in mining of thick coal seam with soft, 3-D numerical simulationin was used to S2S9 face of Da Ping mine, it reveals the damage movement rule of overlying strata in mining roof-coal in "Three Soft" coal seam in the end . Thus it confirms the height of the water flowing fractured zone and tests the simulation result by the theoretical analysis and simple hydrology observation result. it provides a new idea for the application soft overburden in extra- thick seam mining technology.

The Research on Abutment Stress Distribution and Fracture Characteristics of Coal Seam in Longwall Face

2011 ◽  
Vol 361-363 ◽  
pp. 103-107
Author(s):  
Chuan Ming Li
Keyword(s):  
Stress Distribution ◽  
Coal Seam ◽  
Surrounding Rock ◽  
Geometrical Shape ◽  
Horizontal Distance ◽  
Site Testing ◽  
Fracture Characteristics ◽  
Working Face ◽  
Coal Wall ◽  
Overlying Strata

The abutment stress results from the load coming from overlying strata above the influence range of abutment stress and the load which coming from overlying strata above the stress shell passed by the shell. Through the mechanical calculation,this paper analyzed abutment stress distribution and fracture characteristics of coal seam resulted from the load of overlying strata passed by stress shell which exists in surrounding rock of working face, and obtained the laws of abutment stress distribution and fracture in coal seam in combination with numerical simulation and site testing. The characteristics of abutment stress distribution and fracture are related to the geometrical shape of the stress shell, such as height of the stress shell, horizontal distance between top of stress shell and coal wall,and width of stress shell skewback.

scholarly journals Study on the Failure Characteristics of Coal Wall Spalling in Thick Coal Seam with Gangue

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Guosheng Li ◽  
Zhenhua Li ◽  
Feng Du ◽  
Zhengzheng Cao
Keyword(s):  
Stress Distribution ◽  
Coal Seam ◽  
Internal Stress ◽  
External Stress ◽  
Theoretical Research ◽  
Risk Area ◽  
Thick Coal Seam ◽  
Failure Characteristics ◽  
Coal Wall ◽  
Stress Environment

Coal wall spalling is one of the main factors restricting the safe and efficient mining of thick coal seam, and the gangue has an important impact on the coal wall spalling. To obtain the failure characteristics of coal wall spalling in thick coal seam containing gangue, numerical calculation and theoretical research were used to analyze the morphological differences of coal wall spalling with different gangue positions. Besides, the damage depth, width, and stress environment of coal wall panel caused by the position of gangue were mainly studied, and the failure mechanics model of coal seam containing gangue was established by using the stability theory of pressure bar. The results show that, compared with coal wall spalling in coal seam without gangue, coal seam with the lower and middle gangue has a significant weakening effect on the wall spalling, and coal seam with the upper gangue has little effect on the wall spalling. In the case of coal seam with gangue, the upper gangue has the highest risk area of coal wall spalling with the maximum depth and width of 2.0 m and 2.3 m. For coal seam with the upper gangue, the dangerous areas of coal wall spalling are mainly distributed in the vicinity of the gangue; for coal seam without the gangue, they are mainly distributed in the middle of the coal seam. The gangue cannot change the law of the external stress distribution of the coal seam, but it has an obvious impact on the internal stress distribution of the coal seam. With the different positions of the gangue, the stress distribution in the coal seam has a great difference, and the maximum difference is 1.8 MPa. This shows that the stress environment of the coal seam containing gangue has the following typical characteristics: “the external stress is controlled by the overburden fracture, and the internal stress environment is controlled by the gangue.” Through the mechanical analysis of the coal seam containing gangue, it is further verified that the coal seam containing gangue is more prone to spalling at the position of gangue.

Numerical Analysis of Roof Pre-Splitting Roadway Effect in Incline Coal Seam

2014 ◽  
Vol 644-650 ◽  
pp. 1899-1902
Author(s):  
Hua Jin ◽  
Tao Ning ◽  
Bo Yin
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
Coal Seam ◽  
Rock Burst ◽  
Prevention And Control ◽  
New Technology ◽  
Simulation Software ◽  
Concentration Degree ◽  
Roof Strength ◽  
And Control

Roof pre-splitting roadway is a new technology in roof induced rock burst prevention and control of incline coal seam. With the purpose of increasing rock burst prevention and control effective, FLAC3D numerical simulation software was used to analyze stress distribution characteristics and roof pre-splitting effect and the layout of the roof pre-splitting roadway parameters. The results showed that the roof pre-splitting roadway changed roof and floor stress distribution, the stress concentration degree is high in the zone of roof and floor around pre-splitting roadway and the two ribs of pre-splitting roadway, which made the roof strength weakened and easy to break, avoiding a large overhang in the process of mining and rock-burst; The roof pre-splitting roadway led to stress concentration in the range of 5 ~ 10 m, roof effective weakening range 12 m, so the distance of two roof pre-splitting roadway should be more than 20m. The research provided the reference basis for rock burst prevention by roof pre-splitting roadway in the incline coal seam group mining.

scholarly journals Stress and deformation analysis of gob-side pre-backfill driving procedure of longwall mining: a case study

2021 ◽  
Author(s):  
Rui Wu ◽  
Penghui Zhang ◽  
Pinnaduwa H. S. W. Kulatilake ◽  
Hao Luo ◽  
Qingyuan He
Keyword(s):  
Rock Mass ◽  
Stress Distribution ◽  
Coal Seam ◽  
Abutment Pressure ◽  
Longwall Mining ◽  
Vertical Stress ◽  
Floor Level ◽  
Working Face ◽  
Floor Heave ◽  
Stress And Deformation

AbstractAt present, non-pillar entry protection in longwall mining is mainly achieved through either the gob-side entry retaining (GER) procedure or the gob-side entry driving (GED) procedure. The GER procedure leads to difficulties in maintaining the roadway in mining both the previous and current panels. A narrow coal pillar about 5–7 m must be left in the GED procedure; therefore, it causes permanent loss of some coal. The gob-side pre-backfill driving (GPD) procedure effectively removes the wasting of coal resources that exists in the GED procedure and finds an alternative way to handle the roadway maintenance problem that exists in the GER procedure. The FLAC3D software was used to numerically investigate the stress and deformation distributions and failure of the rock mass surrounding the previous and current panel roadways during each stage of the GPD procedure which requires "twice excavation and mining". The results show that the stress distribution is slightly asymmetric around the previous panel roadway after the “primary excavation”. The stronger and stiffer backfill compared to the coal turned out to be the main bearing body of the previous panel roadway during the "primary mining". The highest vertical stresses of 32.6 and 23.1 MPa, compared to the in-situ stress of 10.5 MPa, appeared in the backfill wall and coal seam, respectively. After the "primary mining", the peak vertical stress under the coal seam at the floor level was slightly higher (18.1 MPa) than that under the backfill (17.8 MPa). After the "secondary excavation", the peak vertical stress under the coal seam at the floor level was slightly lower (18.7 MPa) than that under the backfill (19.8 MPa); the maximum floor heave and maximum roof sag of the current panel roadway were 252.9 and 322.1 mm, respectively. During the "secondary mining", the stress distribution in the rock mass surrounding the current panel roadway was mainly affected by the superposition of the front abutment pressure from the current panel and the side abutment pressure from the previous panel. The floor heave of the current panel roadway reached a maximum of 321.8 mm at 5 m ahead of the working face; the roof sag increased to 828.4 mm at the working face. The peak abutment pressure appeared alternately in the backfill and the coal seam during the whole procedure of "twice excavation and mining" of the GPD procedure. The backfill provided strong bearing capacity during all stages of the GPD procedure and exhibited reliable support for the roadway. The results provide scientific insight for engineering practice of the GPD procedure.

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.

Sign in / Sign up

Export Citation Format

Share Document