scholarly journals Slope stability calculation method for highwall mining with open-cut mines

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Juyu Jiang ◽  
Ye Lu ◽  
Dong Wang ◽  
Xinping Han

AbstractSlope stability is a prominent problem for the efficient application and promotion of highwall mining technology, especially when mining residual coal under high and steep end-slope conditions. This study proposes the concept of target time pillar strength based on the required coal pillar service time. Creep tests were performed to measure the time-varying properties of coal shear strength parameters under different loads, and a time-varying function was established by regression. The highwall mining length is divided into three categories based on discontinuous structural plane theory, including goaf, yielding, and elastic zones, all of which are considered to have resistances against shear stress. The basal coal seam is prone to weakening owing to the weight of overlying strata, which may shift the slope failure mode from circular to sliding along the weak layer. Numerical modeling was used to study the influence of the bearing stress and target time strength on the development of the yielding zone at the coal pillar ribs. The coefficients of the three zones were determined, and the temporal and spatial evolution patterns of the shear strength parameters of the weak layer were acquired. A slope stability calculation method is proposed based on rigid body-limit equilibrium theory that can quantify the influence of highwall mining operations on slope stability, which is significant for popularizing highwall mining technology.

2021 ◽  
Author(s):  
Juyu Jiang ◽  
Ye Lu ◽  
Dong Wang ◽  
Xinping Han

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.


2019 ◽  
Vol 98 ◽  
pp. 05005 ◽  
Author(s):  
Natalia Brakorenko ◽  
Anna Leonova ◽  
Aleksey Nikitenkov

We investigate in this article the impact of soil water saturation on the slope stability, using a site in Tomsk city as a case study. The dependency of the shear strength parameters of soil on the degree of soil water saturation has been demonstrated. The paper also provides equations for the calculation of slope stability coefficient under different values of soil water saturation.


2011 ◽  
Vol 97-98 ◽  
pp. 397-401 ◽  
Author(s):  
Zhi Rong Jia ◽  
Jun Shi

One of the main factors that influence the analytic results of slope stability is the determining of mechanical parameters. When the least square method is adopted as the method for determining the rock shear strength parameters, its precondition that the observation errors exist only in one observation variable is always being neglected. By analysis, the calculating of shear strength parameters is divided into three kind of situations, and a new approach to calculate the shear strength parameters is obtained according to the fact that the quadratic sum of distance between line and points in minimum, and the calculating formulae and applying scopes of three different calculating methods are also put forward. A calculating case shows that there are obvious differences among different calculating methods for determining the strength parameters, and it is necessary to select the calculating method based on the observation errors.


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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