Influence of Underground Mining on Failure Mode and Stability of Counter-Tilt Slope in Surface Mines

2012 ◽  
Vol 594-597 ◽  
pp. 80-85
Author(s):  
Dong Wang ◽  
Lan Zhu Cao ◽  
Chun De Piao ◽  
Run Cai Bai
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Underground Mining ◽  
Limit Equilibrium ◽  
Surface Mining ◽  
Stability Calculation ◽  
Deformation And Failure ◽  
Surface Mines ◽  
The Stability ◽  
Overlying Strata

How to demonstrate the deformation and failure mode of the slope under combine surface and underground mining and evaluate its stability scientifically is one of the problems that need urgent solutions in mining engineering. First, the deformation and failure mode of the slope under simple surface mining, the deformation and failure mechanism of the overlying strata affected by underground mining and deformation mechanism of the slope under combined surface and underground mining were analyzed, then the failure mode and the stability calculation method of the slope under combined surface and underground mining was studied. The results show that the failure modes of the slope under combined surface and underground mining involve three patterns: slipping failure, subsiding failure and slipping-subsiding combined failure, that the failure modes and the stability of the slope under combined surface and underground mining be significantly affected by the underground mining positions and the influence be mainly controlled by the length of the latent slide plane of the slope and the weakening degree of the rock masses in the subsidence range. Finally, a limit equilibrium method to calculate the slope stability under combined surface and underground mining was put forward.

Deformation and Failure Characteristics of Embankment upon the Slope in Permafrost Area under Different Foundation Slope

2013 ◽  
Vol 353-356 ◽  
pp. 905-910
Author(s):  
Qian Su ◽  
Jun Jie Huang ◽  
Bao Liu ◽  
Yu Jie Li
Keyword(s):  
Failure Modes ◽  
Centrifuge Modeling ◽  
Experimental Conditions ◽  
Soil Layers ◽  
Deformation And Failure ◽  
Geotechnical Centrifuge ◽  
Gravity Load ◽  
Unstable Failure ◽  
Thawing Depth ◽  
The Stability

To investigate the effect of foundation slope on stability of embankment upon the slope in permafrost area, 3 groups of model tests with different foundation slope are designed using the mechanical similarity based on geotechnical centrifuge modeling, when the freezing-thawing depth of the embankment reaches the greatest. The results show that: (1) The foundation slope has effect on the stability of the embankment. The deformation mainly concentrates on the soil layers above the freezing-thawing interface, and the deformation mutation point takes place at the freezing-thawing interface. (2) According to fracture characteristics and failure severity of the embankment, failure modes can be divided into the cracking failure in shallow layer and in deep layer. (3) The cause of unstable failure is the deficiency of shear resistance strength of the weak belt, the soil layers above the freezing-thawing interface slips along the freezing-thawing interface under gravity load. (4) Under the experimental conditions, the critical value of the foundation slope influencing on the stability of the embankment is about 1:6 when the height of the slope embankment is 5.0 m.

scholarly journals Slope Stability Calculation Method of Highwall Mining with Open Cut Mines as an Example

2021 ◽  
Author(s):  
Juyu Jiang ◽  
Ye Lu ◽  
Dong Wang ◽  
Xinping Han
Keyword(s):  
Slope Stability ◽  
Recovery Rate ◽  
Limit Equilibrium ◽  
Coal Pillar ◽  
Time Dependent ◽  
Universal Method ◽  
Stability Calculation ◽  
Target Time ◽  
Highwall Mining ◽  
Overlying Strata

Abstract Highwall mining machines have been used to recover retained coal at the toe of highwalls and endwalls over the past few decades. However, there has not been a universal method to evaluate the slope stability using highwall mining while maximizing the recovery rate. Based on the required service time of coal pillars, this study proposes the concept of the target time pillar strength. To obtain time-dependent parameters for the coal, time-dependent shear tests were performed on specimens from an open-cut mine in Inner Mongolia. The highwall mining length was divided into three categories based on discontinuous structural plane theory: goaf, yielding, and elastic zones. The three zones were considered to all have resistances against shear stress. The basal coal seam is likely to become weak due to weight from the overlying strata, which may change the slope failure mode from circular to sliding along the weak layer. Numerical modeling was used to study the influence of the overlying strata and target time strength on the yielding zone development at the coal pillar ribs. The coefficients of the three zones were determined and substituted into the Mohr-Coulomb equation to obtain the time-dependent shear strength parameters. Subsequently, the influence of highwall mining on the slope stability was evaluated using the rigid body-limit equilibrium method (LEM). The optimized coal pillar width is determined to maximize the recovery rate without compromising the slope stability.

Coal: A Primer

2016 ◽  
Author(s):  
Richard Revesz ◽  
Jack Lienke
Keyword(s):  
Underground Mining ◽  
Surface Mining ◽  
Underground Mines ◽  
Short Answer ◽  
Environmental Consequences ◽  
Surface Mines ◽  
Coal Beds ◽  
Basic Facts ◽  
Burning Coal ◽  
Mining Coal

This book chronicles almost five decades of efforts by the United States government to reduce the air pollution associated with burning coal, along with the often misleading political rhetoric surrounding those efforts. Given the central role that coal and its environmental consequences will play in our story, it’s helpful at the outset to understand some basic facts about the fuel. Short Answer: A combustible rock. Longer Answer: Coal is a fossil fuel—“fossil” because it’s primarily composed of the preserved remains of ancient plants and “fuel” because it can be burned to create energy. Most of the coal we use today was formed hundreds of millions of years ago when large swaths of the earth were covered in swampy forests. As plant life in these swamps died, it sank to the bottom of the water, where it was eventually buried under additional layers of sediment and slowly decomposed into a soggy, carbon-rich, soil-like substance known as peat. As still more time passed, this peat was further transformed by heat and pressure, a process known as carbonization, into the sedimentary rock we call coal. Short Answer: We mine it, mostly in Wyoming and Appalachia. Longer Answer: There are two basic methods of mining coal: underground mining and surface mining. Surface mining is typically used for shallow coal beds—those buried less than 200 feet deep. Miners access the fuel by simply removing (often with explosives) the trees and soil and rocks that sit atop it. Underground mining, by contrast, is used to extract coal that sits between 300 and 1,000 feet deep. The surface is left relatively undisturbed, and miners dig tunnels through which to enter the mine and retrieve the coal. Historically, underground mining was the more common of these two methods, but today, the majority of U.S. coal is produced at surface mines, which require far fewer workers to produce the same amount of coal. In addition to being cheaper to operate, surface mines are safer: both fatal and serious nonfatal injuries occur about three times more often in underground mines.

scholarly journals Research on the Evolution Characteristics of Rock Mass Response from Open-Pit to Underground Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiabo Geng ◽  
Qihang Li ◽  
Xiaoshuang Li ◽  
Tao Zhou ◽  
Zhifang Liu ◽  
...  
Keyword(s):  
Underground Mining ◽  
Vertical Direction ◽  
Mining Area ◽  
Open Pit ◽  
Measuring Point ◽  
Deformation And Failure ◽  
Ore Body ◽  
Evolution Characteristics ◽  
The Impact ◽  
Overlying Strata

This study is based on the engineering background of pit no. 2 in Jinning Phosphate Mine, China. In order to systematically analyze the movement, deformation, and failure laws of surrounding rocks in underground stopes. The room and pillar method is used to excavate and stop the ore bodies in the mining area. Combined with the similar physical model experiments and discrete element MatDEM numerical simulations, it reveals the deformation and failure laws and evolution characteristics of the surrounding rock of the stope in the process of converting from open-pit to underground mining. The results show the following: (1) Along the inclination of the ore body, the farther the horizontal and vertical displacements are from the underground stope, the less the impact of mining stress. On the other hand, along the inclined vertical direction of the ore body, the farther the measuring point is from the stope, the smaller the range of mining influence will be. (2) In the process of ore body recovery, the rupture of the overlying strata of the stope has an obvious layered structure, with collapse zones, fissure penetrating zones, and microfracture loosen zones appearing from the bottom to top. In addition, the movement and destruction of the overlying strata of the entire stope is an “elliptical arch.” Therefore, the results of similar simulation experiments and numerical simulation are basically consistent.

Study of Failure Modes of Suction Anchors

2011 ◽  
Author(s):  
Qiyi Zhang ◽  
Sheng Dong
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Failure Modes ◽  
Limit Equilibrium ◽  
Element Model ◽  
Ultimate Bearing Capacity ◽  
Engineering Practice ◽  
Element Analysis ◽  
Limit Equilibrium State

Suction foundations are widely used in deep sea and their ultimate bearing capacity which is closely related with failure modes of suction anchor at limit equilibrium state is a key technology in offshore engineering practice. Based on Coulomb friction theory, an exact finite element model is presented in this paper. On the basis of this FEM model, by use of the finite element analysis software ABAQUS, the effect of mooring point and aspect ratio of a suction anchor on the ultimate bearing capacity and its stability are researched in detail. The results show that the ultimate bearing capacity and stability of the suction anchor are affected vastly by the position of mooring point, and the variation of mooring point on the suction anchor can lead to different failure modes. Simultaneously, the results also shows that tilted rotation of the soil along the direction of the mooring force will occur when the mooring point is near the top of the suction anchor, and the soil near the bottom of the fixed anchor rotates around the center of a circle, so the failure mode is called forward-tilted rotation in this paper; A general translation slip of the soil in front of the anchor along the direction of the mooring force will occur when mooring point is below midpoint of suction anchor, so the failure mode is called the translation slip failure mode in this paper. Anticlockwise tilted rotation of the soil along the direction of mooting force will occur when the mooring point is near the bottom of the anchor, and the soil at the top of the anchor rotates around the center of a circle, so the failure mode is called backward-tilted rotation in this paper.

Analysis on Progressive Slipping-Shear Failure Mode of Bedding Slope of Hard Rock with Medium or Large Dip Angle

2013 ◽  
Vol 438-439 ◽  
pp. 1232-1237
Author(s):  
Yu Feng Wei ◽  
De Xin Nei
Keyword(s):  
Failure Mode ◽  
Slope Failure ◽  
Failure Modes ◽  
Shear Failure ◽  
Hard Rock ◽  
Concrete Gravity Dam ◽  
Geologic History ◽  
Deformation And Failure ◽  
The Right ◽  
Bedding Slope

Kala Hydropower Station is located in the midstream of Yalong River in Sichuan Province of China, and the type of dam is concrete gravity dam, with a largest dam height of 129 m, an installed capacity of 1000 MW and a storage capacity of 255.8 million cubic meters. The slope on the right bank of the dam site is mainly composed of hard metasandstone and marbles interbedded with carbonaceous slates and the dip of rock formation is the same as the aspect of slope, so that it is a typical bedding slope. The field survey indicates that the failure of bedding slope of hard rock is not on a common mode of slipping-bending or buckling, but on an uncommon failure mode. The paper introduces a research method that starts with geologic history, analyzes current state and predicts the future failure mode, analyzes the characteristics and phenomenon of slope failure, and adopts the finite element calculation method to analyze the plastic zone resulting from slope deformation. According to the deformation evidence and calculation results, the engineering geologic mechanical theory is used to analyze the deformation and failure mode of slope, and it is indicated that the current and future failure modes of hard rock slope with large thickness are all slipping-shear failure.

scholarly journals Method and Mechanism of Dump Overlying the Bedrock with Large Dip Angle in Opencast Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Hongze Zhao ◽  
Hairui Du ◽  
Zhigang Tao ◽  
Zechen Lin
Keyword(s):  
Shear Strain ◽  
Limit Equilibrium ◽  
Quadratic Function ◽  
Strain Increment ◽  
Open Pit ◽  
Stability Factor ◽  
Deformation And Failure ◽  
Dispersion Degree ◽  
Dip Angle ◽  
The Stability

Dump in the steep area of the open-pit mine is essential for safe production. The bedrock with the bumpy-surface blasting method effectively improves the stabilization of the dumpsite. The effect of the ratio and dispersion degree on the deformation and failure of the dumping bench at the largely inclined area was analyzed. Based on the limit equilibrium method, the equation about the stability factor and the blasted region ratio was deduced. Virtual experiments were performed to address how the ratio and dispersion degree affect deformation and failure. The results showed that the stability factor is a quadratic function of the ratio of the blasted area. The increase in the ratio results in a drastic reduction of displacement, and the direction of displacement significantly changes. The rise in the dispersion degree effectively reduces the displacement and shear strain increment, and the failure mode changes. There is a specific value for the ratio and dispersion degree, making the displacement and shear strain increment little. The research on bumpy surface blasting in this paper provides the theoretical foundation for the dump construction at the site with the large dip angle.

Stability Analysis of Jinghua Gypsum Mine Golf in Jingmen City

2014 ◽  
Vol 580-583 ◽  
pp. 324-328
Author(s):  
Cong Xin Chen ◽  
Kai Zong Xia ◽  
Yuan Bin Dong ◽  
Xiu Min Liu ◽  
Ping Lu Huang
Keyword(s):  
Large Range ◽  
Underground Mining ◽  
Stable State ◽  
Long Term Stability ◽  
Covering Layer ◽  
Small Column ◽  
Short Period ◽  
The Stability ◽  
Overlying Strata

According to golf’s distribution and occurrence situation of Jinghua Gypsum Mine circumstances in Jingmen city, The golf is divided into general golf, filling golf, then the stability of column and covering layer of the two kinds of golf are analysed. It is shown that: For the general golf, A large range of column is stable within a relatively short period of time in the process of underground mining. it will be unstable for local small column because of it was bore weight of overlying strata. After the column was soaked, its strength will be greatly reduced, and the long term stability of column will not be guarantee. Complementary, the covering layer is basically critical stable state; For the filling golf, A large range of column is stable, and the covering layer is also basically critical stable state. It can promote the control of mining disaster and the protection of ecological environment and similar engineering with a high theoretical and practical value.

scholarly journals Stability Assessment of Dangerous Rock Mass of an Overhanging Slope in Puerdu Town, Southwestern China

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Wen-Lian Liu ◽  
Jia-Xing Dong ◽  
Su-Gang Sui ◽  
Han-Hua Xu ◽  
Run-Xue Yang ◽  
...  
Keyword(s):  
Rock Mass ◽  
Failure Modes ◽  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
Difficult Problem ◽  
Characteristic Parameters ◽  
High Position ◽  
Equilibrium Method ◽  
The Stability ◽  
Dangerous Rock Mass

Dangerous rock mass in the overhanging slope of Puerdu town has good free-face condition, high position, and great potential energy, identification and stability evaluation of which is a difficult problem in the disaster prevention. In this paper, the limit equilibrium method was used to evaluate the dangerous rock mass stability in the overhanging slope. Firstly, geomorphic characteristics and the distribution of dangerous rock mass are determined by the field geological survey. Secondly, six dangerous rock masses which may cause more threat are studied, with defining their failure modes and characteristic parameters. Finally, a simplified geological model is established, the stability coefficient of dangerous rock mass under different conditions is calculated by the limit equilibrium method, at the same time, stability analysis of dangerous rock mass is carried out based on the stereographic projection, and the hazard probability is estimated by the empirical formula. Results show that joints obviously developed in the dangerous rock mass of W1, W2, W3, W4, W5, and W6, with falling-type and toppling-type failure modes. In the natural condition, the dangerous rock mass is understable and unstable under the rainstorm and earthquake conditions. Consequently, rainstorm and earthquake are the key triggering factors of the instability and collapse of dangerous rock mass.

scholarly journals Study on the Influence of Water–Rock Interaction on the Stability of Schist Slope

2020 ◽  
Vol 12 (17) ◽  
pp. 7141
Author(s):  
Qian-Cheng Sun ◽  
Can Wei ◽  
Xi-Man Sha ◽  
Bing-Hao Zhou ◽  
Guo-Dong Zhang ◽  
...  
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Structural Characteristics ◽  
Micro Structure ◽  
Intact Specimen ◽  
Rock Interaction ◽  
Structure Changes ◽  
The Stability ◽  
Water Rock Interaction

(1) The studies on the influence of rainfall on slope stability mainly focus on rainfall characteristics and the variation of strength parameters. Few studies pay attention to the micro structure changes of rock mass under long-term rainfall conditions, and the influence of failure mode. (2) Based on nuclear magnetic resonance (NMR) and electron microscopic imaging (Emmi) technology, the micro structure changes and macro deformation characteristics of the schist, under long-term immersion in different liquids are analyzed. (3) After soaking in the deionized water, the uniaxial compression strength of the intact specimen is slightly lower than that of the untreated specimens, but the test process in the elastic compression stage is considerably prolonged, and the failure modes show both shear and slip at the same time. While after soaking in acid solution, the fracture of rock samples with initial cracks can be obviously reduced and healed, which is consistent with the change of micro pore structure. The uniaxial strength and modulus of the intact samples are significantly lower, and only slip failure mode occurred. (4) It shows that water–rock interaction is an important factor influencing the stability of slope besides the external rainfall force, which affects the structural characteristics and mechanical properties of rock.

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