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.

An Application of the Maximum Shear Strain Increment in Searching Sliding Surfaces

2013 ◽  
Vol 423-426 ◽  
pp. 1618-1622 ◽  
Author(s):  
Liu Yong Cheng ◽  
Jian Li ◽  
Shan Xiong Chen ◽  
Xiao Jie Chu
Keyword(s):  
Shear Strain ◽  
Least Squares Method ◽  
Limit Equilibrium ◽  
Quadratic Function ◽  
Strain Increment ◽  
Vertical Line ◽  
Sliding Surface ◽  
Maximum Shear Strain ◽  
Sliding Surfaces ◽  
Different Depths

A slope landslides generally at the place where the shear strain increment is the largest. This position is considered as the standard of defining sliding surfaces to assess the slope stability under the action of the foundation. A new method is proposed to determine the potential sliding surface, which is based on the largest shear strain increment. Firstly, the stress and strain in the slope were calculated by using the finite difference software-FALC3D. Secondly, a series of vertical line would be set in the calculating section. And then the discrete coordinates of the sliding surface, where the shear strain is largest on the vertical line, would be found through programming fish program. At last the position and shape of the sliding surface can be obtained through carrying on curve fitting of the discrete points by using the least squares method. The concept of this method is clear and can reflect the true form of the sliding surface through contrasting with the limit equilibrium method. Sliding surfaces of different depths and distances of slope are researched and a quadratic function is put forward which can describe the trends of glide direction. Three coefficients of the quadratic function were analyzed and the corresponding expression was obtained which can provide a reference to specification revision and engineering.

scholarly journals Research on the Influence of Weak Interlayer in Open-Pit Slope on Stability

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhong Shuheng ◽  
Miao Yinjun
Keyword(s):  
Sliding Mode ◽  
Limit Equilibrium ◽  
Open Pit ◽  
Weak Layer ◽  
Overall Stability ◽  
Weak Interlayer ◽  
Different Depths ◽  
Dip Angle ◽  
The Stability ◽  
Theoretical Results

The weak interlayer in the slope meets with water threatening the overall stability of the slope. Sequestration location of the weak layer has an impact on the stability of the slope. Based on this, taking the south-side slope of Fushun West Open-Pit Mine as the background, the limit equilibrium method was used to study the influence of different depths and dip angles of weak interlayers on the factor-of-safety and sliding mode of the slope. After analyzing the effect, a bottom friction experiment was conducted to verify the theoretical results. The research results show that, as the buried depth of the weak layer becomes larger and the dip angle becomes smaller, the safety factor of the slope increases. Dip angle and depth both affect the sliding mode of the slope. This can provide a reference for study of the influence mechanism of weak interlayer on slope stability in multi-weak-layer slopes.

Research on 2D Limit Equilibrium Method of Slopes Considering the Effect of Horizontal In Situ Stress

2013 ◽  
Vol 671-674 ◽  
pp. 245-250
Author(s):  
Wen Hui Tan ◽  
Ya Liang Li ◽  
Cong Cong Li
Keyword(s):  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
In Situ Stress ◽  
Open Pit ◽  
Open Pit Mines ◽  
Equilibrium Method ◽  
Iron Mine ◽  
The Stability ◽  
Slice Method

At present, in-situ stress was not considered in Limit Equilibrium Method (LEM) of slopes, the influence of in-situ stress is very small on the stability of conventional slopes, but in deep-depressed open-pit mines, the influence should not be neglected. Formula for calculating the Factor of Safety (FOS) under the effect of horizontal in-situ stress was deduced using General Slice Method (GSM) of two-dimensional (2D) limit equilibrium method in this paper，a corresponding program SSLOPE was built, and the software was used in a deep- depressed open-pit iron mine. The results show that the FOS of the slope decreased by 20% when horizontal in-situ stress is considered, some reinforcements must be taken. Therefore, the influence of in-situ stress on slope stability should be taken into account in deep open –pit mines.

scholarly journals Design of Medium Depth Drainage Trench Systems for the Mitigation of Deep Landsliding

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 174
Author(s):  
Federica Cotecchia ◽  
Rossella Petti ◽  
Dario Milella ◽  
Piernicola Lollino
Keyword(s):  
Slip Surface ◽  
Limit Equilibrium ◽  
Drainage System ◽  
Field Studies ◽  
Stability Factor ◽  
Deep Drainage ◽  
Predisposing Factor ◽  
Mitigation Measure ◽  
Transient Seepage ◽  
The Stability

For those slopes where the piezometric regime acts as internal landslide predisposing factor, drainage may represent a more effective mitigation measure than other structural interventions. However, drainage trenches have been generally considered as mitigation measure solely for shallow landslides. More recently, instead, some authors show that the variation in piezometric conditions at large depth is not negligible when medium depth drainage trenches are involved. The paper presents the results of finite element analyses of the transient seepage induced by the installation of systems of drainage trenches of different geometric parameters, and the effect of the drainage system on the stability factor of the slip surface, through 2D limit equilibrium analyses. The pilot region is the Daunia Apennines, where field studies have led to recognize for most of the landslides a “bowl-shaped” slip surface; the results accounting for the Fontana Monte slope at Volturino (Italy), selected as prototype landslide in the assessment of the stabilization efficacy of deep drainage trench systems, is discussed in the following. The study aims at providing indications about the design of the drainage trenches to reduce the pore water pressures on a deep slip surface of such type.

Study on the Influence of Stability for Higher Precipitous Open Pit Slope under Mining Blasting

2011 ◽  
Vol 255-260 ◽  
pp. 3822-3826 ◽  
Author(s):  
Zhi Yu Zhang ◽  
Long Fa Luan ◽  
Ji Yao ◽  
Jian Bin Xie ◽  
Xiang Long Li
Keyword(s):  
Large Deformation ◽  
Limit Equilibrium ◽  
Static Stability ◽  
Open Pit ◽  
Blasting Vibration ◽  
Phosphate Mine ◽  
Stability Of Slope ◽  
The Stability ◽  
Lagrange Element ◽  
Element Method

Based on the hydrological, geologies and slope features of Jianshan phosphate mine in Yunnan province, the geomechanics model of slope was established. Then the static stability of different elevations in mining section was studied by using methods such as the rigid body limit equilibrium method, finite element method, continuum large deformation Lagrange element method. According to the supervise data of the mining blasting, the dynamic response of the slope in blasting was studied by continuum large deformation Lagrange element method, and some suggestions were proposed for following mining blasting. The research results show that the slope was in the stable status before blasting vibration. Current mining blasting vibration has little effect on the stability of slope, but would reduce the safety factor of the top of the slope. Single blasting would enlarge the instantaneous acceleration of the top of the slope in a ratio of 8.8% and 10.8%.

Analysis of the Relative Position of the Slope and Underground Mining Area and its Influence Properties

2013 ◽  
Vol 634-638 ◽  
pp. 3277-3281 ◽  
Author(s):  
Shi Guo Sun ◽  
Hong Yang ◽  
Chun Sheng Li ◽  
Bao Lin Zhang ◽  
Jia Wang ◽  
...  
Keyword(s):  
Slope Stability ◽  
Underground Mining ◽  
Mining Area ◽  
Open Pit ◽  
Stability Factor ◽  
Mining Depth ◽  
Extracellular Region ◽  
Geological Conditions ◽  
Slope Rock ◽  
The Stability

The stability state of slope rock mass is relating to each other’s relative location during the transformation from open-pit to underground mining, it’s the most disadvantageous influence on the slope stability when the underground mining area is located in the toe of slope, and it’s the best influence as in the slope extracellular region. Slope stability factor changes with the geometric dimensions of underground mining increased, but not in direct proportion. Under the condition of constant geometric dimensions of mining area, the influence on slope stability is changing with the mining depth increased. Thus indicating that the influence on slope stability by underground mining has its spatial property, and to determine the specific influence value requires a combination of many factors, such as the relationship of relative spatial position, the geometric dimensions of mining area, engineering geological conditions and so on.

Physical Modelling of Joint Effects on Deformation and Failure of Tunnels

2011 ◽  
Vol 243-249 ◽  
pp. 3205-3210 ◽  
Author(s):  
Hai Jun Zhao ◽  
Feng Shan Ma ◽  
Jie Guo
Keyword(s):  
Failure Mechanisms ◽  
Physical Modelling ◽  
Jointed Rock ◽  
Structural Instability ◽  
Shear Stresses ◽  
Overburden Pressure ◽  
Deformation And Failure ◽  
Shear Slip ◽  
Dip Angle ◽  
The Stability

The deformation and failure mechanisms of tunnels in jointed rock mass with variable orientation and overburden pressures were studied by physical modelling. The deformation and expansion characteristics and regularities of joints and its influence on the stability of tunnels were analyzed. The results shown that the effects of unloading and reactivation of joints, and subsequent shear slip and deformation induced by excavation cause the structural instability of tunnels. The deformation, failure, and instability of surrounding rocks are essentially the continued deformation and repeated failure of joints in varied stress field caused by excavation and overburden pressure. When the dip angle of the joint sets is 75°, the joints have extremely striking influence on the stability of tunnels. In addition, with the increasing of the overburden pressures, the deformation extent and failure rate are sped up prominently due to the rapid increasing of the shear stresses on joint planes.

scholarly journals Examining the Effects of Suction and Nonlinear Strength Envelopes on the Stability of a High Plasticity Clay Slope

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 449
Author(s):  
Mengwei Xuan ◽  
Jack Montgomery ◽  
J. Brian Anderson
Keyword(s):  
Limit Equilibrium ◽  
Friction Angle ◽  
Stability Factor ◽  
High Plasticity ◽  
Slope Failures ◽  
Clay Deposits ◽  
Ring Shear ◽  
High Plasticity Clay ◽  
The Stability ◽  
Cut Slopes

Slope failures in high plasticity clay deposits are common occurrences in many parts of the world. In western and central Alabama, expansive Prairie clays are commonly found, and shallow slope failures have occurred in both fill and cut slopes containing these high plasticity clays. The objective of this study was to examine the effects of suction and the use of nonlinear strength envelopes on the embankment stability of a section of highway AL-5. The testing program consisted of fifteen ring shear tests performed using a Bromhead Ring Shear Device. The results of the tests were used to develop both linear and nonlinear fully softened and residual strength envelopes. The saturated strength envelopes are then used in a limit equilibrium slope stability analysis with and without the effects of suction. The results show stability (factor of safety >1) for all cases except the residual friction angle without suction. Given these results, large slope failures are unlikely to occur in this area, but surficial failures and deformations due to creep may be possible. These results demonstrate the importance of considering the effects of suction and nonlinear strength envelopes when examining the potential for shallow slope failures in high plasticity clays.

scholarly journals Slope stability evaluation and monitoring of Tonglushan ancient copper mine relics

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401879170 ◽  
Author(s):  
Zhigang Tao ◽  
Chun Zhu ◽  
Xiaohui Zheng ◽  
Manchao He
Keyword(s):  
Slope Stability ◽  
Limit Equilibrium ◽  
Warning System ◽  
Open Pit ◽  
Western Slope ◽  
Factors Affecting ◽  
Copper Mine ◽  
Limit Equilibrium Methods ◽  
The Stability ◽  
Major Factors

Due to natural environmental conditions and the effect of man, geological disasters (landslides, earthquakes, etc.) pose a serious threat to ancient relics distributed across China. In consideration of the current situation at the Tonglushan ancient copper mine relics, and on the basis of hydrology and geological engineering conditions of ancient relics, major factors affecting slope stability of ancient relics are analyzed. In light of major working condition types in the slopes of ancient relics, slope stability in relation to earthquakes and rainfall is analyzed using GeoStudio software with limit equilibrium methods. Results indicate that, with sustained rainfall, all slopes in the current reinforcement measure maintain a suitable stabilization status, but slope stability will sharply decline in response to an earthquake. Therefore, the influence of mining blasting activities on slope stability is analyzed. In view of the deformation characteristics of ancient copper mines, the sliding force remote monitoring and warning system based on the constant resistance and large deformation anchor bolt is adopted to continuously monitor the stability of the west slope of the relics. Monitoring results show that the application of “mechanical gun” instead of “explosive blasting” mining technique in the open-pit mine has effectively reduced the influence of mining disturbance on the stability of the western slope. As slope deformation of the relics can be effectively monitored and controlled, our findings provide a theoretical basis to analyze slope stability in other similar cultural relics.

A Study on the Safety Criteria for Dike and Slope Exposed to Vibration

2011 ◽  
Vol 368-373 ◽  
pp. 2142-2146
Author(s):  
Yu Cheng Zhang ◽  
Guang Hua Yang ◽  
Hai Ying Hu
Keyword(s):  
Reduction Method ◽  
Limit Equilibrium ◽  
Safety Margin ◽  
Vibration Velocity ◽  
Inertia Force ◽  
Stability Factor ◽  
Free Vibration Frequency ◽  
Simple Consideration ◽  
Stability Of Slope ◽  
The Stability

Problems and flaws of existing safety criteria for vibration are reviewed. A simple consideration of particle vibration velocity cannot fully reflect the inherent law of effects of explosion earthquake on structures. Sometimes the occurrence of explosions exceeding the standard velocity for safety will not necessarily cause damage to structures and those below the standard velocity for safety may destroy structures. For this reason, the free vibration frequency of structures and the safety margin of the structure should be considered. Based on safe, practical and convenient conditions, that in respect of safety criteria for dike and slope exposed to vibration, two indicators, i.e., stability factor of dike and slope and vibration velocity of particle, can be used to determine the effect of vibration on them is proposed. That is to say, pseudo-static method is adopted to make vibration inertia force equivalent to a static force on slope bars and then strength reduction method or limit equilibrium method is used to calculate the safety factor, which can directly evaluate the stability of slope. In combination with the particle vibration velocity given in specifications, the safety of dike and slope can be determined. Lastly, specific engineering cases are used to validate the rationality of this criterion. This method can serve as a reference for similar projects

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