scholarly journals Numerical Investigation on Time-Dependent Deformation in Roadway

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Yuantian Sun ◽  
Guichen Li ◽  
Junfei Zhang ◽  
Bicheng Yao ◽  
Deyu Qian ◽  
...  
Keyword(s):  
Field Application ◽  
Vertical Deformation ◽  
Rock Mass Properties ◽  
Soft Coal ◽  
Coal Roadway ◽  
Mass Properties ◽  
3D Numerical Model ◽  
The Stability ◽  
Roadway Deformation ◽  
Roof Deformation

The roadway deformation normally relates to time especially for underground coal roadway. The strength of soft coal is low, and therefore the deformation increases gradually under constant stress with time, which is called rheology deformation. In this study, based on a field case, the rock mass properties and deformation data of the roadway were obtained according to the field test. A 3D numerical model was then established, and the rheological deformation including horizontal and vertical deformation of the coal roadway was systematically analyzed. The results showed that the rheological deformation of horizontal sidewall accounts for almost 30% of the whole deformation, and the stable time for such roadway is around 60 days after excavation. The tendency of the roof deformation is similar to the sidewalls, and however, the floor deformation is different. Then the related suggestions for maintaining the stability of such roadway were proposed, which is useful in-field application.

Stress Distribution Characteristics in Rock Surrounding Heading Face and its Relationship with Temporary Supporting

2014 ◽  
Vol 568-570 ◽  
pp. 1684-1689
Author(s):  
Zhong Han Chen
Keyword(s):  
Coal Mine ◽  
Surrounding Rock ◽  
Zenith Distance ◽  
Rock Stability ◽  
Coal Roadway ◽  
Temporary Support ◽  
The Stability ◽  
Roadway Deformation ◽  
Mine Roof ◽  
Roof Deformation

To solve the problem of underground tunneling face from the empty top, using FLAC3D analysis software, surrounding rock stability for coal roadway 2-1121 of Ganhe Coal Mine are analyzed in numerical calculation. (1) During the tunneling, distance drivage face head-on 0.5-1m at the roof of roadway deformation and destruction features are more obvious, the two sides of roadway are even more significant. (2) Ganhe Coal Mine roof deformation has been established with different empty the experience formula of the zenith distance, obtained Ganhe underground tunneling face reasonable empty zenith distance is 3.5m. (3) Temporary support can obviously reduce roof deformation, reduce thickness of plastic zone of the top, to improve the stability of surrounding rock tunneling faces.

Reasons and Control Countermeasures of Special Soft Coal Roadway Deformation in Liangbei Coal Mine

2013 ◽  
Vol 671-674 ◽  
pp. 1144-1149
Author(s):  
Le Tuan Cheng ◽  
Jia Lin Zhang ◽  
Zheng Sheng Zou ◽  
Qing Bo Li
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Mining Area ◽  
Gas Content ◽  
Deformation And Failure ◽  
Gas Outburst ◽  
Soft Coal ◽  
Coal Roadway ◽  
Roadway Stability ◽  
Roadway Deformation

B1 coal seam located at -550m level in Liangbei Coal Mine is a typical "three-soft" seam. The coal roadway with a depth of 610-750m lies under the critical softening depth of the roadway, and its support difficulty coefficient is 1.5-2.0. The coal has poor air permeability, high gas content and high gas pressure, so danger degree of the gas outburst is relatively strong. The coal seam was destroyed in a disastrous state by more than 100 boreholes for gas outburst prevention during the excavation. This results in the difficulty in the roadway support. Engineering geological characteristics of the coal roadway at 11 mining area are introduced. Based on the engineering geo-mechanics method, the reasons of deformation and failure of the coal roadway are analyzed. In view of problems in excavation and support, as well as the type of the coal roadway deformation mechanism, the borehole parameters are optimized for the gas outburst prevention, and bolt-net-cable coupling support with high convex steel-belt is used to control the coal roadway stability at 11 mining area. Practice shows that the effect is fine.

Optimization on Gateway Section of Soft Coal Seam and Hard Roof and Supporting Technology

2011 ◽  
Vol 90-93 ◽  
pp. 622-625
Author(s):  
Lu Chen ◽  
Chuan Wei Zang ◽  
Feng Hai Yu ◽  
Xiang Kun Yu
Keyword(s):  
Plastic Zone ◽  
Coal Seam ◽  
Field Application ◽  
Geological Condition ◽  
Hard Roof ◽  
Soft Coal ◽  
Production Safety ◽  
Geological Conditions ◽  
The Stability ◽  
Soft Coal Seam

Support invalidity of a roadway have a largely influence on production safety of coal mines, especially the soft coal roadway, which deforms heavily. To solve this problem, it began from the gateway section optimization, based on the actual geological condition of Chang-gouyu Mine. The computational model was established up to optimize tunnel shapes using FLAC3D. The scopes of plastic zone, stress field, displacement field were compared and analysed for different shapes of roadway. The irregular trapezoid section is adopted, then the bolt support parameters were designed and field application was done. By using the irregular trapezoid, the stress distribution around the roadway is improved and the deformation and plastic zone is decreased. Under the geological conditions of the soft coal seam and hard roof strata, the stability of roadway was effectively controlled by using optimized trapeziform cross-section and bolting support.

Supporting Technics of Easily Mudding and Ultrahigh Roadway in Soft Coal Rock

2014 ◽  
Vol 988 ◽  
pp. 211-217 ◽  
Author(s):  
Zhen Zhang
Keyword(s):  
Simulation Method ◽  
Field Application ◽  
Structure Stability ◽  
Deformation And Failure ◽  
Soft Coal ◽  
Floor Heave ◽  
Coal Rock ◽  
Stress Environment ◽  
Roadway Deformation ◽  
Two Sides

According to the situation of the great height wall, soft and weak surrounding rocks and sliming characteristics of the 15# coal west-third panel sump in the Gushuyuan mine, the deformation characteristics and mechanism of the sump were analyzed by field survey, laboratory tests and the numerical simulation method. The results show that the sump deformation and failure were determined by its low strength, weakness structural, sliming characteristics and excavation disturbance. The roadway deformation occurs mainly in the middle, upper and lower of the sides and the floor. A comprehensive solution is proposed, including sealing surrounding rocks, strengthening soft and weak surrounding rocks, strengthening the structure stability, improving the surrounding rocks stress environment. This method was applied in the coal mine. Field application results show that this method was suitable for control sump deformation, the maximum roadway roof subsidence is 15 mm, the two sides convergence is 30mm, and the maximum amount of floor heave is 21mm.

scholarly journals Dynamic Analysis of Blasting Effect on Nanjung Tunnel Stability

2020 ◽  
Vol 2 (1) ◽  
pp. 1-10
Author(s):  
Alio Jasipto ◽  
Nuhindro Priagung Widodo ◽  
Ganda Marihot Simangunsong ◽  
Simon Heru Prasesetyo ◽  
Made Astawa Rai ◽  
...  
Keyword(s):  
Strain Level ◽  
Silty Clay ◽  
The Finite Element Method ◽  
Rock Mass Properties ◽  
Tunnel Stability ◽  
Twin Tunnel ◽  
Tunnel Model ◽  
Mass Properties ◽  
The Stability ◽  
Shaped Section

This study aims to dynamically analyze blasting conducted in the Nanjung tunnel. Nanjung Tunnel is a twin tunnel that has a horseshoe-shaped section with each tunnel having a dimension of 10.2 m x 9.2 m, and 230 meters in length. The layers rock of this tunnel include silty clay, sandstone and dacite. Blasting was carried out on one of the tunnels consisting of dacite rock, having a 75-90% RQD and UCS 49-61 MPa. During the blast, PPV measurements were taken at several points around the tunnel using a minimate.Dynamic analysis is done by building a Nanjung Tunnel model on the RS2 software with the finite element method. Input data in this modeling is endeavored to approach actual conditions in the field, such as tunnel geometry, rock mass properties, and blasting plans carried out at STA 30-32 tunnels 2. This modeling is expected to produce PPV that is close to actual PPV and the results of this model will be continued to the stability analysis tunnel 1.Modeling results indicate that the tunnel 1 condition is stable during blasting. The stability of tunnel 1 based on smallest strength factor on the roof is around 2.6. Stability also seen from the strain level in dacite and sandstone rocks which are 0.07% and 0.38%. These strain levels are still permissible according to the Sakurai strain level diagram, 1983.

Modelling of thermal rock mass properties at the potential sites of a Swedish nuclear waste repository

2009 ◽  
Vol 46 (6) ◽  
pp. 1042-1054 ◽  
Author(s):  
Jan Sundberg ◽  
Pär-Erik Back ◽  
Rolf Christiansson ◽  
Harald Hökmark ◽  
Märta Ländell ◽  
...  
Keyword(s):  
Rock Mass ◽  
Nuclear Waste ◽  
Nuclear Waste Repository ◽  
Rock Mass Properties ◽  
Mass Properties ◽  
Waste Repository

Mechanism Analysis of Anchor Bolt and Cable Synergistic Action in Coal Roadway Support

2014 ◽  
Vol 716-717 ◽  
pp. 735-738 ◽  
Author(s):  
Peng Cheng ◽  
Jian Zhang ◽  
Ai Qing Liu
Keyword(s):  
Simulation Method ◽  
Paper Analysis ◽  
Synergistic Action ◽  
Mechanism Analysis ◽  
Anchor Bolt ◽  
Tension Distribution ◽  
Coal Roadway ◽  
Cable Force ◽  
Roadway Support ◽  
The Stability

Aiming at the current situation of anchor bolt and cable arrangement in mine roadway support, the paper analysis the mechanical characteristics and mechanism of bolts and cables, and numerical simulation method is used to comparison and analysis of pre-tension distribution characteristics under different anchor bolt-cable arrangement. The research indicated that separate anchor bolt-cable layout in different sections, anchor bolt and cable force stable equilibrium, coordinate with each other, at this time roadway surrounding rock of shallow and deep pretension distribution more reasonable, can play a role of bolt anchor cable synergistic action, and form the best pre-tension load-bearing structure, which is helpful to keep the stability of coal roadway.

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