Stressed-strained state of an artificial rock mass in the zone of a quarry near the face

1990 ◽  
Vol 26 (4) ◽  
pp. 338-343
Author(s):  
Kh. I. Aglyukov ◽  
L. M. Ivantsov
Keyword(s):  
Rock Mass ◽  
Strained State ◽  
Artificial Rock ◽  
The Face

scholarly journals Directional Hydraulic Fracturing (DHF) of the Roof, as an Element of Rock Burst Prevention in the Light of Underground Observations and Numerical Modelling

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 562
Author(s):  
Marek Jendryś ◽  
Andrzej Hadam ◽  
Mateusz Ćwiękała
Keyword(s):  
Rock Mass ◽  
Hydraulic Fracturing ◽  
Coal Mining ◽  
Rock Burst ◽  
Coal Mine ◽  
Seismic Activity ◽  
Black Coal ◽  
Directional Hydraulic Fracturing ◽  
Before And After ◽  
The Face

The following article analyzes the effectiveness of directional hydraulic fracturing (DHF) as a method of rock burst prevention, used in black coal mining with a longwall system. In order to define changes in seismic activity due to DHF at the “Rydułtowy” Black Coal Mine (Upper Silesia, Poland), observations were made regarding the seismic activity of the rock mass during coal mining with a longwall system using roof layers collapse. The seismic activity was recorded in the area of the longwall itself, where, on a part of the runway, the rock mass was expanded before the face of the wall by interrupting the continuity of the rock layers using DHF. The following article presents measurements in the form of the number and the shock energy in the area of the observed longwall, which took place before and after the use of DHF. The second part of the article unveils the results of numerical modeling using the discrete element method, allowing to track the formation of goafs for the variant that does not take DHF into consideration, as well as with modeled fractures tracing DHF carried out in accordance with the technology used at “Rydułtowy” coal mine.

scholarly journals Experimental Study on Hydromechanical Behavior of an Artificial Rock Joint with Controlled Roughness

2019 ◽  
Vol 11 (4) ◽  
pp. 1014
Author(s):  
Seungbeom Choi ◽  
Byungkyu Jeon ◽  
Sudeuk Lee ◽  
Seokwon Jeon
Keyword(s):  
Rock Mass ◽  
Rock Joint ◽  
Great Influence ◽  
Rock Joints ◽  
In Situ Tests ◽  
Joint Roughness ◽  
Artificial Rock ◽  
Geometric Conditions ◽  
Bedding Planes ◽  
Hydraulic Aperture

Rock mass contains various discontinuities, such as faults, joints, and bedding planes. Among them, a joint is one of the most frequently encountered discontinuities in rock engineering applications. Generally, a joint exerts great influence on the mechanical and hydraulic behavior of rock mass, since it acts as a weak plane and as a fluid path in the rock mass. Therefore, an accurate understanding on joint characteristics is important in many projects. In-situ tests on joints are sometimes consumptive in terms of time and expenses so that the features are investigated by laboratory tests, providing fundamental properties for rock mass analyses. Although the behavior of a joint is affected by both mechanical and geometric conditions, the latter are often limited, since quantitative control on the conditions is quite complicated. In this study, artificial rock joints with various geometric conditions, i.e., joint roughness, were prepared in a quantitative manner and the hydromechanical characteristics were investigated by several laboratory experiments. Based on the results, a prediction model for hydraulic aperture was proposed in the form of ( e h / e m ) 3 = exp ( − 0.0462 c ) × ( 0.8864 ) J R C , which was a function of the mechanical aperture, joint roughness, and contact area. Relatively good agreement between the experimental results and predicted value indicated that the model is capable of estimating the hydraulic aperture properly.

Static and Dynamic Stability Analysis on Artificial Rock Mass Slope Using Strength Reduction Method

2013 ◽  
Vol 368-370 ◽  
pp. 1774-1780
Author(s):  
Shi Yan ◽  
Hai Tao Du ◽  
Qi Le Yu ◽  
Han Yan
Keyword(s):  
Rock Mass ◽  
Stability Analysis ◽  
Slope Stability ◽  
Dynamic Stability ◽  
Rock Slope ◽  
Reduction Method ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Artificial Rock ◽  
Static And Dynamic Stability

This paper focuses on stability analysis of an artificial rock mass slope by a nonlinear finite element method (FEM). For a long time, rock slope stability problem is always an important research issue in the field of geotechnical engineering, which is related to human life and property safety as well as engineering security and efficiency. Therefore, the stability analysis and evaluation on rock slope is of great significance. The static and dynamic stability analysis on the artificial rock mass slope of WuAn power plant in China is carried on respectively in this paper by using the strength reduction method and FLAC3D software. In this analysis, static and dynamic instability criterions are enumerated, and the static and dynamic safety factors are calculated with the developed criterions of the displacement mutation, respectively. The analysis results show that the artificial rock mass slope is basically stable. It indicates that analyzing slope stability with strength reduction method is feasible.

scholarly journals Modeling of influence of stresses on indicators of resistance of mining rocks to mechanical destruction

2019 ◽  
Vol 109 ◽  
pp. 00104
Author(s):  
Serhii Tynyna ◽  
Ihor Chobotko ◽  
Liliya Frolova ◽  
Tetyana Butyrina
Keyword(s):  
Rock Mass ◽  
Coordinate System ◽  
Stress Tensor ◽  
Rock Breaking ◽  
Infinite Cylinder ◽  
Mechanical Destruction ◽  
Cylindrical Coordinate ◽  
The Face ◽  
Improper Integrals ◽  
Analytical Expressions

The article deals with the problem of determining the expression for the components of the stress tensor of a rock mass that is exposed to rock-breaking tools. In solving this problem, the natural tension of the rocks and the stresses arising ahead, in the plane and on the boundary of the face of the cylindrical excavation were taken into account. Formulation presented in the form of a semi-infinite cylinder whose axis coincides with the axis ̅Z of the coordinate system. The solution is obtained in a cylindrical coordinate system in the form of analytical expressions, which is carried out by numerical integration of improper integrals.

scholarly journals Variation of Rock Mass Pressure during Tunnel Construction in Phyllite Stratum

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Jianxun Chen ◽  
Yanbin Luo ◽  
Yao Li ◽  
Lijun Chen ◽  
Chuanwu Wang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Bearing Capacity ◽  
Logistic Function ◽  
Field Monitoring ◽  
Surrounding Rock ◽  
Tunnel Construction ◽  
Time And Space ◽  
Monitoring Method ◽  
Supporting Structure ◽  
The Face

In this paper, the field monitoring method is used to study the variation of rock mass pressure during the construction of a tunnel in phyllite stratum, and three functions are used to fit and analyze the variation of rock mass pressure with deformation, excavation time, and space. The results show the following (1) When the deformation increases significantly, the rock mass pressure decreases firstly and then increases. This is caused by the insufficient bearing capacity of the rock mass in the arch foot of the supporting structure after the excavation of the upper bench, which leads to a settlement of supporting structure and surrounding rock. (2) Compared with other kinds of fitting functions, the logistic function can better characterize the variation of the pressure of surrounding rock with deformation, excavation time, and distance from the face. This paper provides a reliable reference for the design and construction of the tunnel in phyllite stratum. The logistic function can be used to present and predict the change of rock mass pressure with deformation, excavation time, and space in similar rock mass conditions.

scholarly journals Strength test of 3D printed artificial rock mass with pre-existing fracture

2020 ◽  
Author(s):  
Youyu Wang ◽  
Li Wang ◽  
Fanfei Meng ◽  
Kang Chen
Keyword(s):  
Rock Mass ◽  
Strength Test ◽  
Artificial Rock ◽  
3D Printed

scholarly journals An Influence Study of Face Length Effect on Floor Stability under Water-Rock Coupling Action

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Baojie Fu ◽  
Bo Wang
Keyword(s):  
Rock Mass ◽  
Coal Seam ◽  
Mine Pressure ◽  
Length Effect ◽  
Pressure Relief ◽  
Limestone Aquifer ◽  
Study Results ◽  
Face Length ◽  
The Face ◽  
Floor Stability

The Taiyuan Formation limestone aquifer and Ordovician limestone aquifer are widely distributed in the coal seam floor of coal measures in North China; the water hazard safety problem of the stope floor under the influence of mining is very prominent. The risk of the water inrush from the coal seam floor is closely related to the degree of full exploitation, so it is necessary to study the stability of the stope floor under aquifer conditions, especially the influence of the working face length effect on floor stability. Through numerical simulation of water-rock coupling action, the mine pressure behaviors of the water-resisting floor under different face lengths were analyzed based on the measured formation permeability coefficient. The Fish program was used to adjust rocks entering the plastic failure state into a strain softening model to investigate the influence of the face length effect, the damage degree of the water-resisting floor, and the morphology and deformation bearing capacity of the failure zone. The results show the following: (1) the face length effect is one of the main influence factors of the failure mode and failure degree of surrounding rocks in the stope; (2) as the face length increases, the obvious pressure relief zone of surrounding rocks presents a staged change, and the obvious pressure relief zone at the seam roof and floor is in an obvious “reverse saddle shape”; (3) the closer to the seam floor, the more remarkable the rock softening characteristic because of the compaction action of gangues caving from the roof; and (4) the rock mass close to the seam floor undergoes local tensile failure, and the water-resisting floor near the coal wall at two sides mainly bears compaction-shear action, leading to compression-shear failure of the rock mass at the floor and formation of water-conducting fractures. The study results can provide a reference for taking precautionary measures of safety mining above a confined aquifer.

scholarly journals Relationship of the discontinuities and the rock blasting results

2018 ◽  
Vol 26 (1) ◽  
pp. 208-218
Author(s):  
S. Yahyaoui ◽  
A. Hafsaoui ◽  
A. Aissi ◽  
A. Benselhoub
Keyword(s):  
Rock Mass ◽  
Rock Blasting ◽  
Static Properties ◽  
Joint Orientation ◽  
Free Face ◽  
Single Hole ◽  
Anticlockwise Direction ◽  
The Face ◽  
Geological Discontinuities ◽  
Relationship Of

The Geological discontinuities such as joint are the most common discontinuities present in the rock mass. A model scale study was carried out to evaluate the effect of the joints on rock blasting. Single hole tests at three selected burdens (optimum, less than optimum and more than optimum) were done on six different joint orientations. The joint orientation angles were 0°, 30°, 60°, 90°, 120° and 150° rotating in anticlockwise direction from the floor of the bench in a plane perpendicular to the free face. Bench models of dimensions 515x335x215 mm with a bench height of 50 mm were prepared by binding sandstone slabs of 25 mm thickness with an adhesive. The models were blasted by n°6 electric detonators. The dynamic and static properties of sandstone are given. The bench crater formed and the fragmentation produced were predominantly influenced by the position of charge with respect to the joint orientation. Severe toes were noticed in models with vertical joints and with joints dipping away from the face. Over breaks were observed in horizontally bedded models and in models with joints dipping towards the free face. Over breaks were observed in horizontally bedded models and in models with joints dipping towards the free face. The size of the broken fragments at 20 mm burden was found to be finer than the fragments obtained at 30 mm and 40 mm burdens for all joint orientations except vertical.

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