Parameters for the Design of Tailings Dams

1975 ◽  
Vol 12 (2) ◽  
pp. 235-261 ◽  
Author(s):  
Hari K. Mittal ◽  
Norbert R. Morgenstern
Keyword(s):  
Pore Pressure ◽  
Water Table ◽  
Laboratory Data ◽  
Poor Performance ◽  
Pressure Measurements ◽  
Liquefaction Potential ◽  
Tailings Dams ◽  
Infiltration Test

Tailings dams differ from conventional earthfill structures in that much more time is available to optimize design since their construction is extended over a longer period. Laboratory data are presented on a variety of tailings sands which indicate that they are relatively strong and incompressible. Poor performance is likely to result from inadequate seepage control and instability due to liquefaction. In order to take advantage of opportunities for ongoing design, in situ permeability and density monitoring is needed together with pore pressure measurements. An infiltration test for the determination of permeability above the water table is proposed. In situ density determinations are made by driving a nuclear probe into the sands. The latter technique offers considerable promise for evaluating liquefaction potential of natural and fill deposits. Field experience is used to illustrate the application of the techniques.

scholarly journals Jet Fuel Deposition and Oxidation: Dilution, Materials, Oxygen, and Temperature Effects

1995 ◽  
Author(s):  
Steven Zabarnick ◽  
Paula Zelesnik ◽  
Rebecca R. Grinstead
Keyword(s):  
Thermal Stability ◽  
Electrode Materials ◽  
Batch Reactor ◽  
Jet Fuel ◽  
Pressure Measurements ◽  
Good Technique ◽  
Antioxidant Concentration ◽  
Fuel Deposition

The quartz crystal microbalance (QCM) and pressure measurements are used for determination of jet fuel thermal stability in a batch reactor. The QCM is able to monitor extremely small amounts of deposition in situ, while the pressure measurements provide qualitative data on the oxidation process. The dependence of the deposition amount was monitored as a function of the oxygen availability for two fuels. Also, the effect of QCM electrode materials was investigated. Deposition and oxidation were compared for the following electrode materials: gold, aluminum, silver, and platinum. We also studied the effect of dilution on oxidation and deposition. Jet fuel was diluted with increasing amounts of hydrocarbon solvent. It was observed that this dilution procedure can help characterize a fuel’s effective antioxidant concentration. Fuel dilution is also shown to be a good technique for improving thermal stability characteristics of poor fuels. Additionally we have studied the temperature effect on deposition for two fuels over the range 140 to 180 C.

Liquefaction potential of silts from CPTu

2007 ◽  
Vol 44 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Dawn A Shuttle ◽  
John Cunning
Keyword(s):  
Finite Element ◽  
Pore Pressure ◽  
Earthquake Engineering ◽  
Critical State ◽  
Pressure Ratio ◽  
Excess Pore Pressure ◽  
Liquefaction Potential ◽  
Triaxial Cell ◽  
Excess Pore

Silt tailings (slimes) are difficult materials to test in that, like sands, it is extremely difficult to obtain undisturbed samples and subsequently re-establish them in a triaxial cell for element testing in a laboratory in anything approaching their in situ condition. Evaluation of silt tailing behaviour has to depend on in situ tests, and the piezocone (CPTu) in particular. However, CPTs in silt generate substantial excess pore pressure and there is no established methodology to evaluate the measured responses in terms of soil properties, as drained sand-based CPT interpretation is inapplicable. A case history of particularly loose silt tailings is reported in which the National Center for Earthquake Engineering Research (NCEER) liquefaction assessment method would lead to uncertainty in the liquefaction potential. However, the extremely high CPTu excess pore pressure ratio, Bq, and low dimensionless CPT resistance, Qp, at this site indicates liquefaction is likely occurring during pushing of the CPT. Detailed finite element simulations of the CPT using a critical state model provided an effective stress framework to evaluate the in situ state parameter of the silt from the measured CPT data. This framework shows that the group of dimensionless CPT variables Q(1 – Bq) + 1 is fundamental for the evaluation of undrained response during CPT sounding. And, despite the high silt content, the interpretation indicates that the tailings are indeed liquefiable.Key words: liquefaction, CPT, silt, finite element, critical state.

scholarly journals Estimation of field capacity from ring infiltrometer-drainage data

2014 ◽  
Vol 38 (6) ◽  
pp. 1765-1771 ◽  
Author(s):  
Theophilo Benedicto Ottoni Filho ◽  
Marta Vasconcelos Ottoni ◽  
Muriel Batista de Oliveira ◽  
José Ronaldo de Macedo
Keyword(s):  
Field Capacity ◽  
Soil Science ◽  
Matric Potential ◽  
Volumetric Soil Water Content ◽  
Double Ring ◽  
Infiltration Test ◽  
Drainage Data ◽  
Volumetric Soil Water

Field capacity (FC) is a parameter widely used in applied soil science. However, its in situ method of determination may be difficult to apply, generally because of the need of large supplies of water at the test sites. Ottoni Filho et al. (2014) proposed a standardized procedure for field determination of FC and showed that such in situ FC can be estimated by a linear pedotransfer function (PTF) based on volumetric soil water content at the matric potential of -6 kPa [θ(6)] for the same soils used in the present study. The objective of this study was to use soil moisture data below a double ring infiltrometer measured 48 h after the end of the infiltration test in order to develop PTFs for standard in situ FC. We found that such ring FC data were an average of 0.03 m³ m- 3 greater than standard FC values. The linear PTF that was developed for the ring FC data based only on θ(6) was nearly as accurate as the equivalent PTF reported by Ottoni Filho et al. (2014), which was developed for the standard FC data. The root mean squared residues of FC determined from both PTFs were about 0.02 m³ m- 3. The proposed method has the advantage of estimating the soil in situ FC using the water applied in the infiltration test.

scholarly journals Liquefaction potential of sand tailings dams evaluated using a probabilistic interpretation of estimated in-situ relative density

2016 ◽  
Vol 15 (2) ◽  
pp. 9-18
Author(s):  
Gabriel Villavicencio A ◽  
Pierre Breul ◽  
Claude Bacconnet ◽  
Andy Fourie ◽  
Raúl Espinace A
Keyword(s):  
Relative Density ◽  
Probabilistic Interpretation ◽  
Liquefaction Potential ◽  
Tailings Dams
Sign in / Sign up

Export Citation Format

Share Document