BACKGROUND AND AIMS A previous paper (Annals of Botany 103: 673-685) described formation of clayey pavements in lateral root catchments of eucalypts colonizing a recently formed sand dune in south-west Western Australia. Here chemical and morphological aspects of their formation at the site are studied. METHODS Chemical and physical examinations of soil cores through pavements and sand under ...

distinct target of this paper is development of 'implicit discrete element method (dem)' in three dimensions for estimating the ultimate bearing capacity of shallow foundations on layered (non-homogeneous) soils consisting of sand overlying sand or clay overlying sand and vice versa with different shear resisting parameters. in this method, shear resisting parameters and density of ea...

Studies of populations of the multimammate rat Mastomys natalensis in Morogoro, Tanzania, show that soil texture appears to influence the population abundance and distribution of these rats in agricultural fields. The lowest rodent population abundance was found on sandy clay soils (F((2, 5)) = 8.42; P= 0.025). The population abundances of M. natalensis on sandy clay loam and sandy loam soils d...

[1] We report results on the effects of porewater pH and transients in porewater flow on the deposition and mobilization of colloid-sized clay particles within unsaturated sand columns. The deposition rates of illite under steady-flow conditions were essentially independent of pH, while the deposition rates of kaolinite nearly doubled as the pH decreased from 7.4 to 4.6. Mobilization of kaolini...

Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solu...

the present paper investigates the influence of stabilization with cement, peat ash, and silica sand on permeability coefficient (kv) of compacted clay, using a novel approach to stabilize the clay with peat ash as a supplementary material of cement in the compacted and stabilized soil. in order to assess the mentioned influence, test specimens of both untreated and stabilized soil have been te...

The main purpose of the current research is comparing the results of Artificial Neural Network (ANN) with Adaptive Neuro-Fuzzy Inference System (ANFIS) with regard to determination of the importance of soil properties affecting clay dispersibility. After taking samples from two depths of 0-40 and 40-80 cm, the spontaneous and mechanical dispersions of clay were recorded using both weighing and ...

Water saturation and cation exchange capacity are the most significant parameters used to calculate a hydrocarbon zone potential. In clean formations, by applying the famous Archie model, which assumes that in the formation the only electric conductor is the formation water, the water saturation can be calculated. Additionally, in shaly sand formations this assumption may not be true as the ion...

To study the influence of sand particles on strength and dry–wet cycle characteristics cement-solidified South China coastal soft clay, a series clay samples with different contents sizes were prepared, unconfined compression (UCS) tests, tests under seawater freshwater conditions, scanning electron microscopy X-ray diffraction carried out. The test results show that UCS cement–sand-solidified ...