The role of capillary water in the stability of tailing dams

Zandarín, Maria Teresa; Oldecop, Luciano; Rodríguez, Roberto; Zabala, Francisco

doi:10.1016/j.enggeo.2008.12.003

Cited by 84 publications

(44 citation statements)

References 8 publications

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“…More details about these relationships can The soil water retention curve proposed by van Genuchten (1980) [4] is given by equation 1, which relates the effective degree of saturation (S e ) (calculated as a function of the current (S), the maximum (S s ), and the residual (S r ) degree of saturation) to suction s=-p w through the air entry suction parameter s e . In equation 2, the parameter s e is in turn related to the porosity (φ) through parameter η which controls the rate at which s e deviates from its reference value s eo when φ deviates from its reference value φ o [10,11]. Similarly, equation 3 describes the dependency of the saturated permeability (k s ) on its reference value k so and the difference between φ and its reference value φ o , as proposed by Kozeny (1927) [12].…”

Section: Hydraulic and Mechanical Modelsmentioning

confidence: 99%

Characteristics of failure mass and safety factor during rainfall of an unsaturated slope

Gallipoli

Sánchez

et al. 2016

E3S Web Conf.

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Abstract.Water is an important factor triggering destabilization of soil masses in slopes, particular in unsaturated condition. Rainfall and snow melting are some of the main sources of natural water which frequently induce unsaturated slope failure in arid/semi-arid region or in active layers (i.e. frequently frozen/thawed layers) in permafrost. If the slopes are in coastal environment or adjacent to a stream, the soil materials from the sliding masses might be carried away by waves and currents, which can further lead to soil erosion problem. Therefore, characterization of the failure mass and safety factor is critical both for evaluation of slope failure hazard but also for erosion problem. This paper presents a method to study unsaturated slope stability including characterizing the size of failure and the safety factor by analyzing a theoretical unsaturated homogeneous slope subjected to rainfall infiltration. The slope is modelled numerically by the finite element method. A shear strength reduction technique is modified for unsaturated soils and employed to evaluate the factor of safety and the extent of the sliding mass. The results show that the size of failure and the factor of safety vary over the rainfall event. Notably, the extent of the sliding mass for unsaturated slopes depends strongly on the infiltration depth. Large global sliding surface tends to be the dominant mechanism if the infiltration depth is very shallow or very deep. Conversely, local restricted sliding surface becomes more dominant if the infiltration is approximately at a certain critical value.

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Section: Hydraulic and Mechanical Modelsmentioning

confidence: 99%

Characteristics of failure mass and safety factor during rainfall of an unsaturated slope

Gallipoli

Sánchez

et al. 2016

E3S Web Conf.

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“…01 respectively. Parameters s e (related to the air entry suction) and k s (saturated permeability) are linked to soil porosity ö through parameters ç, ö 0 , s e0 and k s0 according to equations (2) (Kozeny, 1927;Rodriguez, 2006;Zandarín et al, 2009). Model parameter m controls the shape of the water retention curve and the permeability function.…”

Section: The Modelmentioning

confidence: 99%

Rainfall-induced differential settlements of foundations on heterogeneous unsaturated soils

Le¹,

Gallipoli²,

Sánchez³

et al. 2013

Géotechnique

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This study stochastically investigates the rainfall-induced differential settlement of a centrally loaded, rigid strip foundation on an unsaturated soil with spatially varying values of either preconsolidation stress or porosity. The differential settlement (between the two foundation ends) is calculated at various times during rainfall by way of a coupled, hydro-mechanical, finite-element analysis. The Barcelona basic model describes the mechanical behaviour of the soil, and the van Genuchten relationships describe water retention and permeability. The variability of soil properties is modelled by means of random fields with spatial correlation in the framework of a Monte Carlo simulation. The study demonstrates that the occurrence of rainfall-induced differential settlements can be consistently analysed using concepts of unsaturated soil mechanics and random field theory. Results show that differential settlements can be vastly underpredicted (or even completely missed) if random heterogeneity and partial saturation are not simultaneously considered. The variation of differential settlements and their statistics during the rainfall depend on the magnitude of the applied load and the statistics of soil variability. Moreover, the transient phase of infiltration and a spatial correlation length equal to the width of the foundation pose the highest risk of differential settlement.

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“…It should be noted that there are some case studies about nite element analyses of tailings dams presented in the literature, (e.g., [6][7][8][9][10][11][12][13][14][15][16][17]. To the authors' knowledge, the validity of 2D axisymmetric analyses for a dam corner has not been addressed before.…”

Section: Introductionmentioning

confidence: 99%

Comparison of three dimensional and two dimensional axisymmetric finite element analyses of a corner section of a tailings da

et al. 2017

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Abstract. This paper presents three-dimensional (3D) and two-dimensional (2D) axisymmetric nite element analyses of a corner of a tailings dam. The analyses were performed to: (i) locate tension and/or low-compression zones and evaluate slope stability during sequential raising of the dam corner, and (ii) nd whether the results of 2D axisymmetric analyses could be reliable for the dam corner. The corner is a potentially weak section of the dam, where tension and/or low-compression zones may develop. Development of such zones inside the dam corner can lead to cracks and initiation of internal erosion. The results of both the 3D and 2D axisymmetric analyses indicated that (i) tension and/or lowcompression zones were located in vicinity of surface of the dam corner mainly above the phreatic level, and (ii) the dam corner was stable up to the planned height if it was gradually strengthened with rock ll berms on the downstream side. The results of 2D axisymmetric analyses showed a fairly good agreement with those of 3D analyses. It is concluded that 2D axisymmetric analyses are appropriate for this dam corner. This implies that signi cant computational time can be saved by utilizing 2D analyses instead of 3D analyses.

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The role of capillary water in the stability of tailing dams

Cited by 84 publications

References 8 publications

Characteristics of failure mass and safety factor during rainfall of an unsaturated slope

Characteristics of failure mass and safety factor during rainfall of an unsaturated slope

Rainfall-induced differential settlements of foundations on heterogeneous unsaturated soils

Comparison of three dimensional and two dimensional axisymmetric finite element analyses of a corner section of a tailings da

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