Application of a rock buttress in the design of slopes of a strip coal mine adjacent to a highway

1993 ◽  
Vol 30 (3) ◽  
pp. 391-408 ◽  
Author(s):  
R. Ulusay ◽  
M.F. Yolerì ◽  
V. Doyuran

Eskihisar open pit mine, located at Yatagan, southwest Turkey, produces thermal coal for a power generating plant. As mining of strips advanced southwards, instability appeared to be highly critical due to the movements in the southeast wall slopes adjacent to the state highway running parallel to the pit boundary. This situation called for an immediate response to initiate a detailed geotechnical investigation program and to redesign the pit slopes. This paper outlines the most probable mode and mechanism of instability along the southeast wall, as well as field and laboratory studies, results of back analysis, discussion of the data requirements, and results of slope stability analyses performed to ensure adequate overall stability. The studies revealed that the most critical failures may occur along two or three planar surfaces, by combination of fault, bedding plane, and localized strata steepening adjacent to the fault, in multiplanar failure mode controlled by faulted blocks. The stability is sensitive to changes in length of the lower part of the basal sliding surface, as well as to the configuration and shear strength of black and highly plastic underclay. The effects of a buttress of intact rock and slope flattening on the stability are compared and discussed. Key words : back analysis, multiplanar failure, shear strength, slope stability, toe buttressing.

1996 ◽  
Vol 33 (1) ◽  
pp. 58-79 ◽  
Author(s):  
Resat Ulusay ◽  
Dinçer Çaglan ◽  
Fehmi ArIkan ◽  
M Fatih Yoleri

The stability of spoil piles in surface coal mines is an important factor in the successful exploitation of coal reserves. Spoil pile instability must be avoided not only to ensure negligible risk in both personnel and equipement but also to prevent increased production costs. Since mining began at the Eskihisar strip coal mine, southwest Turkey, stability problems have been experienced in both spoil piles adjacent to highwalls (slices) and outside dumping areas. This paper outlines the results of field and laboratory investigations performed to describe the causes and mechanism of pile instabilities threatening production along the highwalls. Back-analysis of failures and monitoring data have revealed that failures occur along planar surfaces that define two-wedge shaped blocks. In addition, shear strength of the moist underclay at the base of piles and changes in the floor dip are the controlling factors in the development of failures. It is also noted that sharp decreases in shear strength after peak values for the the underclay indicated that weak basal planes exhibit a shear strength at or approaching the residual value at the time of failure. Results show that failures are most likely initiated along the spoil &#150 natural ground interface and propagate into spoil mass. Three possible remedial measures have been evaluated by carrying out two-dimentional stability analyses, and the most effective method for improving spoil pile stability appeared to be spreading of a rockfill material on the floor after coal production. Key words: back-analysis, biplanar wedge failure, pile instability, rockfill blanket, shear strength.


Author(s):  
Shalaho Dina Devy ◽  
Pretty Permatasari Hutahayan

The stability of open pit slopes in Biangan district, West Kutai Regency, East Kalimantan Province, is greatly influenced by groundwater conditions. The existence of groundwater reduces the shear strength of the materials which causes a decrease in the stability value of pit slopes. The main objective of this study is to assess the impact of groundwater on the stability of the low wall and high wall pit mining. Groundwater modeling is used to determine the prediction of groundwater level on the pit slope which determines the value of the slope stability. Slope stability analysis in this study was performed using the Finite Element Method, producing output in the form of strain zones, deformation and displacement values. Therefore, the Strength Reduction Factor (SRF) approach was used, which is a gradual reduction of shear strength until the values of cohesion and friction angles reach minimums and the slopes are at a critical state. Groundwater modeling results indicate that groundwater flows to the Biangan river with hydraulic heads between 76 and 108 meters above sea level. Based on the analysis using the Finite Element Method, the stability values of the pit slopes, which are influenced by groundwater, are 0.65 on the low wall and 1.40 on the high wall. The total displacements are 0.019 meters on the low wall and 0.002 meters on the high wall.  The impact of groundwater on the slope is an increase in the slope load. This increases the materials’ thrust and reduces the shear strength of the materials which reduces the rock mass that can function as a water seepage path. Thus, the recommendation for low wall pit construction is a safety factor of 7.79 with a total displacement of 0.020 meters.


2012 ◽  
Vol 204-208 ◽  
pp. 241-245
Author(s):  
Yang Jin

The stability of soil slope under seepage is calculated and analyzed by using finite element method based on the technique of shear strength reduction. When the condition of seepage or not is considered respectively, the critical failure state of slopes and corresponding safety coefficients can be determined by the numerical analysis and calculation. Besides, through analyzing and comparing the calculation results, it shows that seepage has a negative impact on slope stability.


2011 ◽  
Vol 84-85 ◽  
pp. 729-732 ◽  
Author(s):  
Jun Guo ◽  
De Qing Gan ◽  
Yu Zhang ◽  
Wei Hang Zhang

The paper analyzed major factors that influence the stability of open-pit slope and established the GM (1, N) model based on the program of Xingshan strip mine, which provided an effective method for evaluating the slope stability.


2019 ◽  
Vol 24 (1) ◽  
pp. 13
Author(s):  
I Nyoman Ramia ◽  
I Wayan Arya ◽  
I Wayan Wiraga ◽  
I G A G I G A G Suryanegara

The shear strength value is one of the important points in calculation of slope stability. One way to obtain the shear strength value is to do a direct shear test in laboratory. Like the cliff reinforcement study at Utama Mandala Uluwatu temple which is currently experiencing crack, it is necessary to test the shear strength of the limestone material at the cliff of the temple . There is no limestone testing equipment in the laboratory of the Civil Engineering Department, so that innovation is needed on the existing sliding test equipment. In this study innovation was carried out on how to test the soil shear strength so that it could be used to test the limestone shear strength. The test is done by moving two limestone surface that have been formed based on the mold tool which shape is circle. The shear strength slope at Uluwatu temple, which is currently experiencing crack in dry condition is . The shear strength value is used for calculating slope stability at Uluwatu Temple which is currently experiencing crack wich . The calculation used is curved slope stability by only calculate the life load and dead load. From the calculation of the stability of the slope, the safety factor is 1.15.


2021 ◽  
Vol 44 (3) ◽  
pp. 1-13
Author(s):  
José Fernando Jucá ◽  
Alison Norberto ◽  
José Ivan Santos Júnior ◽  
Fernando Marinho

For geotechnical and environmental reasons, landfills are positioned above the regional water table and thus are formed in unsaturated conditions. This condition can be different if the drainage system and the rain regime of the site are such that they create a level of internal liquid in the landfill. During January and February 2019, excessive movements occurred in the slopes of the Brasília sanitary landfill. A geotechnical investigation indicated that the raised leachate level caused by the clogging of the drainage system contributed to the landfilled waste movements. The limit equilibrium analysis was used to predict the relationship between leachate level and slope stability. In order to understand the process that led to the rupture, flow and stability analysis by limit equilibrium were performed. The parameters associated with flow, water retention capacity, and shear strength were obtained based on literature evaluations. In addition, data from tests were used, which allowed to define more accurately the distribution of pore pressures of liquid that led to the failure. This study allowed to define the cause of failure and also to establish the role of the drainage system in maintaining the stability of the landfill. The studies indicated that although the gain of shear strength of landfill due to the unsaturated condition is negligible, the process of flow in unsaturated medium, associated with climatic aspects, are fundamental for a medium- and long-term analysis.


2020 ◽  
Vol 194 ◽  
pp. 04043
Author(s):  
Guo Xiaoli ◽  
Yan Jiancheng ◽  
Li Xueliang ◽  
Wen Xin ◽  
Li Xingli

The dumps in the open-pit mining area in the eastern grassland are prone to landslides due to the fragile ecological environment, so it is inevitable to reshape the dump slopes. In order to explore a more scientific method for slope shaping of open-pit mine dump, slope stability analysis were used to compare effect of three types of slope-type (wave-shaped, slope-shaped and step-shaped slope shaping method)in outside dumping site of Baori Hiller open-pit mine. The results show that the slope stability is negatively correlated with the slope angle, and the stability of different shaping slopes is realized as wave-shaped slope (F=2.711)> Slope-shaped slope(F=2.513)>Step-shaped slope(F=1.047), in which the wave type and slope type are all within the safe range, but the step type slope is unstable; in consideration of cost, stability and erosion resistance, it is better to set the slope angle of the dump to 15°.The wave-shaped shaping method of the natural dumping of the excavation field outside the Baori Hiller open-pit mine has the best effect and is worth promoting.


2013 ◽  
Vol 634-638 ◽  
pp. 3277-3281 ◽  
Author(s):  
Shi Guo Sun ◽  
Hong Yang ◽  
Chun Sheng Li ◽  
Bao Lin Zhang ◽  
Jia Wang ◽  
...  

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.


2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Wenchen Fan ◽  
Ping Cao ◽  
Ke Zhang ◽  
Kaihui Li ◽  
Chong Chen

Chengmenshan copper mine, located at Jiujiang city in the Jiangxi Province, is a rarely lakeside open-pit mine in China. Since the open-pit is very close to Sai Lake, the seasonally changed water level and the distance between lake and slope have great influence to the stability of open-pit slope. Based on the drill data and geological sections, a numerical model of the slope is built. With the fluid-mechanical interaction associated, the stability of the slopes is numerically analyzed, in which different lake water levels and lake-slope distances are taken into consideration. The comparative analysis shows that a larger lake-slope distance can promise better slope stability and weaken the sensitivity of slope stability to water. The stability of slopes with different heights is analyzed to find that the stability weakens and the sensitivity is enhanced with the height increasing. To the most serious situation, the slope height and the lake water level being 238 m and 17.2 m, respectively, theFsvalue equals 1.18945 which is extremely closed to the allowable safety factor of 1.20 for slope design. According to the minimumFsfor slope design, the minimum distance between lake and open-pit slope is found to be 60 m.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ju-yun Zhai ◽  
Xiang-yong Cai

By analyzing the characteristics of expansive soil from Pingdingshan, China, the shear strength parameters at different water contents, dry densities, and dry-wet cycles of expansive soil are obtained. It is found that, at higher soil-water content, the internal friction angle is 0° and the shallow layer of expansive soil slope will collapse and destroy; this has nothing to do with the height of the slope and the size of the slope. The parameters of soil influenced by atmosphere are the ones which have gone through dry-wet cycles, and the parameters of soil without atmospheric influence are the same as those of natural soil. In the analysis of slope stability, the shear strength parameters of soil can be determined by using the finite element method, and the stability coefficient of the expansive soil slope can be calculated.


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