Stability of open-pit mining slope: a case study of Barun mine

doi:10.16265/j.cnki.issn1003-3033.2025.S2.0031

Abstract

Abstract:

To systematically assess the slope stability of the open-pit mining stope, the Barun open-pit mine in Inner Mongolia was taken as the example. The limit equilibrium method and two-dimensional numerical simulation method were used to conduct stability analysis on the current overall slope and the final slope at the design end, respectively, and carry out the sensitivity study of geotechnical parameters. The results show that the potential failure mode of the slope presents a composite characteristic. The stability coefficients of the current slope under both self-weight and self-weight plus blasting conditions meet the requirements of the specifications. At the end of the design, the slope is in a stable state under the conditions of water content/drainage. The two-dimensional numerical simulation results (stability coefficient 1.32) further verify the slope stability. The stability coefficient is sensitive to the change in the friction angle, while the influence of the change in cohesion is relatively weak. Both the current slope and the designed final slope demonstrate good stability under both operating conditions. According to the optimization requirements of the stripping ratio, the slope angle can be moderately increased when the top position of the slope is maintained, but the rise in water level will lead to a decrease in the stability coefficient.

Key words: open-pit mine, slope stability, limit equilibrium, numerical simulation, sensitivity analysis

CLC Number:

X915.5

DU Wenxiu, YAN Lu. Stability of open-pit mining slope: a case study of Barun mine[J]. China Safety Science Journal, 2025, 35(S2): 196-202.

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岩石类型	重力密度Γ/ (kN·m^-3)	黏聚力C/ kPa	内摩擦角φ/ (°)	弹性模量E₀/ GPa	泊松比ν	点荷载强度I/ MPa	抗压强度σ/ MPa
长石板岩	29.49	401	33.4	39.91	0.27	3.43	47.18
白云岩	30.57	368	34.7	40.97	0.26	6.62	73.95
碳质板岩	27.19	133	37.5	29.73	0.31	3.01	32.03

安全等级	荷载组合Ⅰ	荷载组合Ⅱ
Ⅰ	1.25~1.20	1.23~1.18
Ⅱ	1.20~1.15	1.18~1.13
Ⅲ	1.15~1.10	1.13~1.08

状态	工况1下F₀			工况2下F_S			备注
状态	M-P法	Spencer法	Janbu法	M-P法	Spencer法	Janbu法	备注
疏干	1.330	1.352	1.315	1.268	1.289	1.253	稳定
含水	1.299	1.330	1.279	1.239	1.271	1.217	稳定

代表宽度/m	调整前后	F		整体坡角变化/(°)
代表宽度/m	调整前后	M-P法	Spencer法	整体坡角	变化值
570	调整前	1.330	1.352	34.9	+1.0
570	调整后	1.213	1.239	35.9	+1.0

C/kPa	φ/(°)	F₀	C值变化率/ %	F₀变化率/ %
360	20	1.080	20	7.4
330	20	1.044	10	3.8
300	20	1.006	0	0
270	20	0.970	-10	-3.6
240	20	0.930	-20	-7.6