OPEN PIT SLOPES BACK-ANALYSIS IN COMPLEX ROCK FORMATIONS (GARD COLLIERY, CdF, FRANCE)

Author(s):  
D. HANTZ ◽  
J. ARCAMONE ◽  
J. LAVERSANNE
Author(s):  
C González-Nicieza ◽  
M Álvarez-Fernández ◽  
O Mora ◽  
E Amor-Herrera

2020 ◽  
Vol 7 (4) ◽  
pp. 714-724
Author(s):  
Zhao Hongze ◽  
Wang Dongyu ◽  
Ma Ming ◽  
Zheng Kaihui

AbstractIn light of the complex and dynamic mechanical properties of evolving weak strata in open-pit mines, and the consequent difficulty of determining their mechanical parameters, this study uses the ultimate balance theory, along with the back analysis method combined with monitoring data on field displacement, to carry out parameter inversion using the FLAC3D numerical simulation software. The edge slope of a working pit of the Weijiamao open-pit mine was used as research object to this end. As the results obtained by the constitutive model were consistent with the field monitoring data, the evolving weak strata in the slope and the position of the landslide in the mine could be obtained. The landslide was directed northeast. The mechanism of the edge slope of the working pit was identified as unloading shear failure, and the feasibility of the method of parameter inversion was verified. The internal friction angle ϕ and cohesion C of evolving weak strata in the slope of the open-pit mine were also obtained, where this compensated for the deficiency of laboratory tests and enabled the transformation from qualitative to quantitative analysis. This can provide a reliable basis for the safe operation of open-pit mines.


2002 ◽  
Vol 6 (3) ◽  
pp. 175-180
Author(s):  
Seong-Seung Kang ◽  
Jun-Mo Kim ◽  
Katsuhiko Kaneko ◽  
Yuzo Obara

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.


2016 ◽  
Vol 10 (1) ◽  
pp. 448-460 ◽  
Author(s):  
C.B. Zhou ◽  
R. He ◽  
N. Jiang ◽  
S.W. Lu

Due to the complexity of multiple rocks and multiple parameters circumstance, various parameters are often reduced to only one parameter empirically to generalize geological conditions, ignoring the really influential parameters. A developed method was presented as a complement to 3D displacement inversion to obtain the relative important parameters under complex conditions with limited computational work. Furthermore, this method was applied to a high steep slope in open-pit mining to investigate field applicability of the developed system. Back analysis was conducted in the reality of the east open-pit working area of Daye Iron Mine and propositional steps were presented for parameters solving in complex circumstance. Firstly, multi-factor and single-factor sensitivity analysis were carried out to classify rock mass and mechanical parameters respectively according to the extent of their effects on deformations. Secondly, based on the results, main influence factors were selected as inversion parameters and taken into a 3D calculating model to get the displacement field and stress field, all of which would be the artificial network training samples together with inversion parameters. Thirdly, taking the real deformations as input for the trained back propagation (BP) neural network, the real material mechanical parameters could be obtained. Finally, the results of trained neural network have been confirmed by field monitoring data and provide a reference to obtain the matter parameters in complicated environment for other similar projects.


1986 ◽  
Vol 23 (2) ◽  
pp. 164-173 ◽  
Author(s):  
G. E. Rawlings

Potential exploitation of the 500 m thick coal deposit at Upper Hat Creek, British Columbia, required detailed investigation of the sequence of Tertiary tuffaceous rocks surrounding the coal and the overlying surficial materials. Studies have shown that extensive bentonitic slide deposits partially cover the coal body on the west side of Hat Creek valley; part of this area is currently active. A translational debris slide of approximately 17 × 106 m3 volume and 2 km length is moving across the northwest boundary of the proposed pit into the valley bottom.Detailed field investigations complemented by laboratory testing have defined the basal plane of sliding and permitted a back-analysis to be made. From measured piezometric pressures, the mobilized shear strength on the failure plane is calculated to be [Formula: see text], cr′ = 0, which is largely in accord with laboratory test results.Slope stability in thick montmorillonite-rich claystones/siltstones is known to present difficulties, as evidenced by the Panama Canal excavations. Consideration is given to the engineering significance of bentonitic slides and preventive measures that might be adopted in their control. Key words: active slide, Tertiary, claystone, montmorillonite, open pit, coal, monitoring, residual strength, piezometric pressures.


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