The causes and effects of aging in quick clays

1985 ◽  
Vol 22 (3) ◽  
pp. 335-346 ◽  
Author(s):  
Ghislain Lessard ◽  
James K. Mitchell
Keyword(s):  
Calcium Carbonate ◽  
Pore Water ◽  
Iron Sulfide ◽  
Carbonic Acid ◽  
Iron Hydroxide ◽  
Liquid Limit ◽  
Key Words Aging ◽  
Liquidity Index ◽  
Aging Phenomenon ◽  
Effects Of Aging

The physicochemical properties of a clay from La Baie, Quebec were found to be typical of Champlain quick clays: very low plasticity, liquidity index greater than 3, sensitivity greater than 500, and pH of about 9.5. The mineralogy is characterized by the abundance of primary or "rock flour" minerals such as feldspar, quartz, amphibole, and calcite, with illite as the principal clay mineral. The pore water chemistry consists predominantly of sodium bicarbonate. Low concentrations of sulfate, calcium, and magnesium and high alkalinity and pH are attributed, in part, to anaerobic sulfate-reduction processes taking place in situ.Quick clay samples stored in the laboratory showed signs of aging regardless of the storage procedure. The remoulded strength and the liquid limit increased with time, whereas the sensitivity, the liquidity index, and the pH decreased. The water content, plastic limit, and undisturbed strength remained practically unchanged. The pore water concentrations of calcium, magnesium, and sulfate increased by severalfold.The aging phenomenon is attributed, for the most part, to the oxidation of iron sulfide, which results in the formation of iron hydroxide and sulfuric acid. The production of acid causes the dissolution of calcium carbonate, which increases the concentration of divalent cation in the clay, thereby reducing interparticle repulsion and increasing the remoulded strength. The oxidation of organic matter, resulting in the formation of carbonic acid, also contributes to the aging by its effect on the solubility of calcium carbonate. Key words: aging, chemical reactions, physicochemical phenomena, sensitivity, time effects.

Iron Sulfide Oxidation as Influenced by Calcium Carbonate Application

2003 ◽  
Vol 32 (3) ◽  
pp. 773-780 ◽  
Author(s):  
L. R. Hossner ◽  
J. J. Doolittle
Keyword(s):  
Calcium Carbonate ◽  
Iron Sulfide ◽  
Sulfide Oxidation

scholarly journals Relationship between consistency parameters and granulation of fen soils

2013 ◽  
Vol 12 (3) ◽  
pp. 121-128
Author(s):  
Krzysztof Wilk
Keyword(s):  
Complex Analysis ◽  
Linear Equations ◽  
Clay Fraction ◽  
Building Design ◽  
Liquid Limit ◽  
Soil Parameters ◽  
Geotechnical Parameters ◽  
Substrate Quality ◽  
Liquidity Index ◽  
Clay Fraction Content

Determination of bearing capacity requires knowledge of the ground strength parameters. The best way to appreciate soil properties is the use of the direct research methods. In the case of less responsible buildings, projected on the simple ground structure, it often seems reasonable to adopt conservative soil parameters without performing a complex analysis. The base for determination the values of the geotechnical parameters is the estimation based on the correlation between the mechanical and geotechnical parameters of soil. It is important not only for the new building design, but also to facilitate the verification of the substrate quality during the execution of the work. This paper presents the relationship between granulation (clay fraction content) and soil consistency parameters (plastic limit, liquid limit, plasticity index and liquidity index). The analyzed values are determined as a result of alluvial ground studies. These soils were consequent upon the accumulation of river. The founded relationships were described by linear equations and were compared with the results presented in the geotechnical literature. These comparisons often show a significant effect of regional ground forming  conditions on the parameters of consistency.

scholarly journals Spotted Hyena Optimizer and Ant Lion Optimization in Predicting the Shear Strength of Soil

2019 ◽  
Vol 9 (22) ◽  
pp. 4738 ◽  
Author(s):  
Moayedi ◽  
Bui ◽  
Anastasios ◽  
Kalantar
Keyword(s):  
Shear Strength ◽  
Liquid Limit ◽  
Spotted Hyena ◽  
Key Factors ◽  
Ant Lion Optimization ◽  
Liquidity Index ◽  
Ant Lion ◽  
Artificial Neural Network Ann ◽  
Metaheuristic Techniques ◽  
Clay Percentage

Two novel hybrid predictors are suggested as the combination of artificial neural network (ANN), coupled with spotted hyena optimizer (SHO) and ant lion optimization (ALO) metaheuristic techniques, to simulate soil shear strength (SSS). These algorithms were applied to the ANN for counteracting the computational drawbacks of this model. As a function of ten key factors of the soil (including depth of the sample, percentage of sand, percentage of loam, percentage of clay, percentage of moisture content, wet density, liquid limit, plastic limit, plastic Index, and liquidity index), the SSS was considered as the response variable. Followed by development of the ALO–ANN and SHO–ANN ensembles, the best-fitted structures were determined by a trial and error process. The results demonstrated the efficiency of both applied algorithms, as the prediction error of the ANN was reduced by around 35% and 18% by the ALO and SHO, respectively. A comparison between the results revealed that the ALO–ANN (Error = 0.0619 and Correlation = 0.9348) performs more efficiently than the SHO–ANN (Error = 0.0874 and Correlation = 0.8866). Finally, an SSS predictive formula is presented for use as an alternative to the difficult traditional methods.

Distributions of Ferrous Iron and Sulfide in an Anoxic Hypolimnion

1984 ◽  
Vol 41 (2) ◽  
pp. 286-293 ◽  
Author(s):  
Robert B. Cook
Keyword(s):  
Pore Water ◽  
Solubility Product ◽  
Iron Sulfide ◽  
Water Flux ◽  
Sediment Pore Water ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Anoxic Hypolimnion ◽  
Decomposition Of Organic Matter

In the anoxic hypolimnion of Lake 227, Experimental Lakes Area, northwestern Ontario, ΣH2S exhibits a mid-depth maximum, while Fe2+ increases with depth. At the mid-depth ΣH2S maximum and below, saturation with respect to amorphous FeS is reached, and the concentration of ΣH2S is limited by the high Fe2+ concentrations, in accord with the FeS solubility product. Values for pKsp[Formula: see text] for FeS determined from the ΣH2S maximum and below averaged 3.16 in 1979 and agree well with other in situ and laboratory measurements. In the top 10 cm of sediment, pore water ΣH2S and Fe2+ are in equilibrium with amorphous FeS. Analyses of cores confirms the existence of an iron sulfide phase. Fe2+, which is produced in the pore water from the decomposition of organic matter, increases to concentrations at which siderite may form, although the presence of siderite has not been verified. Comparison of calculated pore water fluxes of Fe2+ with the observed increase of Fe2+ in the anoxic hypolimnion reveals that about 90% of the observed flux originates at the sediment–water interface, while the remainder is derived from pore water flux.

The correlation of index properties with some basic engineering properties of soils

1978 ◽  
Vol 15 (2) ◽  
pp. 137-145 ◽  
Author(s):  
C. P. Wroth ◽  
D. M. Wood
Keyword(s):  
Soil Mechanics ◽  
Liquid Limit ◽  
Engineering Properties ◽  
Cone Penetrometer ◽  
Plastic Limit ◽  
The North ◽  
The United Kingdom ◽  
Liquidity Index ◽  
Remoulded Soil ◽  
The North Sea

Experimental evidence is produced to show that it is reasonable to assign a unique strength to all soils when at their respective liquid limits, and to redefine the plastic limit as the water content at which the strength is 100 times that at the liquid limit. Combining these assumptions with ideas of critical state soil mechanics it is then possible to relate the compression index of the remoulded soil to its plasticity index, and to suggest a unique relation between remoulded strength and liquidity index, irrespective of actual values of liquid and plastic limits. Field data from the Gulf of Mexico and from the North Sea are presented in support of these relations. The predictions of strength are best for overconsolidated clays, having water contents near the plastic limit.Recently in the United Kingdom the cone penetrometer has become the recommended test for determination of the liquid limit, in preference to the Casagrande test. Having redefined the plastic limit it would be logical to use the cone penetrometer to determine this too, by using cones with different weights. Experimental data are shown to illustrate and support this proposal.

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