Clayey sand

Cover design The ET cover was installed in 1999 and consists of a 3-ft silty sand/clayey sand layer, which overlies a 2-ft foundation layer. The cover soil was placed in 18-in. lifts and compacted to 95% with a permeability of <3 x 10 5 cm/s. Native vegetation was planted, including artemesia, salvia, lupines, sugar bush, poppy, and grasses. 

Vertisols in Madagascar formed on basalt and marl contain very high Cr (200-540 mg/kg), while alluvial soils have 190 mg/kg Cr (Aubert and Pinta, 1977). In vertisols derived on alluvions, Pb is in the range of 20-45 mg/kg, while the average Cr in saline soils of the region is from 1-22 mg/kg. Vertic soils on marl and basalt contain 700-2400 mg/kg Mn. In soils derived on clayey sands and alluvions, Zn content is 105 mg/kg. Soils formed on alluvions contain 115 mg/kg Ni. 

Convenience store 2,800 Groundwater and soil—clayey sands 3 30,000... 

Clayey sand CS 5-15 mm Coherence very slight Cannot be molded. Clay is 5-10%. As above... 

Coarse sandy Coarse to touch sand grains can be seen with the naked eye 1. The Sands sand (S), loamy sand (LS), clayey sand (CS)... 

Up the section, the Old Euxinian deposits are gradually replaced by the sediments of the Uzunlarian Formation (end of the Middle Pleistocene). The boundary between these formations is rather conventional it is traced by the reduction in the number of brackish-water mollusk species and the increase in the abundance of the representatives of euryhaline Mediterranean fauna. In the stratotypical section on the coast of Lake Uzunlarian, this formation is represented by two layers. The lower layer is formed by clayey sands and silts, which, along with brackish-water and fresh-water mollusks and benthic foraminifers, contain numerous shells of euryhaline Mediterranean mollusks (Cerastoderma glaucum, Abra ovata, and others). Above, one finds gray-green clays with interlayers of coquina matter mostly formed by marine Mediterranean species. 

The aim of this work is to study the effect of polyamide strips on engineering properties of lime stabilized clayey sands. 

Stabilize clayey sand within reasonable time, and... 

Modifying the engineering properties of clayey sand using polyamide strips. 

Two important parameters can be considered and discussed, when polyamide 66 as reinforcing fibers is used in lime stabilized clayey sand samples namely compressive and tensile strength. In essence, in soil stabilization one of the most important factors that should be considered is the modification of tensile strength. Because, as a general rule, soils like other construction materials such as concrete and asphalt mixtures has low tensile strength. 

In our previous studies [2,3], we have shown that for lime-stabilized clayey sand, a parabolic behavior for the stress- strain curve is expeeted. Hence, for our polyamide reinforced materials, a similar behavior can be observed. This is presented in equation 2 for stabilized speeimens containing 15% lime ... 

In general, most clayey sands can be successfully stabilized with lime [2]. However, the addition of polyamide 66 strips can significantly improve the engineering properties of stabilized clayey sand and moderates the cracks propagation. A typical cracks distribution in a polymeric reinforced specimen in tension as well as in compression is shown in Figures 3 and 4 respectively. The overall results of this study indicate that lime/polyamide stabilizer composite is performing adequately. 

There is no doubt that lime migration is usually oeeurs in the eontext of diffusion of clayey sand in the presence of stabilizers. Coneeptually, the parameters that eontrol this phenomenon should be those assoeiated with diffusion proeess. It is also elear that lime... 

When lime is added to clayey sand for modification of its engineering properties, is called lime-modified clayey sand. Now in this study, when polyamide fiber is used for the same propose, it should termed differently. Our resulting material is referred to as reinforced... 

The strength and stiffness of the clayey sand is well improved using the lime/polymerie stabilizer. 

The results indicate that the lime/polyamide can be a good candidate for stabilization of clayey sand. 

Table 3 lists examples of more than a dozen different chemical types of river water. Although Ca and HCO j" are generally dominant, Mg dominance over Ca + can be found in rivers draining various lithologies such as basalt, peridotite, serpentinite, dolomite, coal, or where hydro-thermal influence is important (Semliki). Sodium may dominate in sandstone basins, in black shales (Powder, Redwater in Montana), in evaporitic sedimentary basins (Salt), in evaporated basins (Saoura), and where hydrothermal and volcanic influence is important (Semliki, Tokaanu). rarely exceeds 4% of cations, except in some clayey sands, mica schists, and trachyandesite it exceeds 15% in extremely dilute waters of Central Amazonia and in highly mineralized waters of rift lake outlets (Semliki, Ruzizi). 

Bidoclio, G., P. Offermann, and A. Saltelli. 1987. Neptunium migration in oxidizing clayey sand. Applied Geo-chem. 2 275-284. 

P Palaeosol horizons Palaeosols on sand (Ps) palaeosols on silts and clays (Psc) silt and clays w/rhizocretions (Fr) massive sand w/rhizocretions (Smr) Tabular to discontinuous and patchy 0.1-1 m thick 0.1 to > 1 km lateral extent Muds, silts, very fine to medium silty and clayey sand/sandstones Nodular, platy and rod concretions, and type 2 and type 3 (vadose) tabular units... 

Type 2 tabular units lack original sedimentary structures and are often associated with reddened clays and clayey sands from overbank fine (OF), palaeosol (P) and interdune (ID) deposits (Table 1 Fig. 6). Micritic calcite is the main cement, and micrite-spar textures, grain dissolution, alveolar structures, circumgranular cracking and meniscus cement are common. Type 2 tabular units are subdivided by outcrop morphology into massive, platy, wavy bedded, fractured and laminar types. 

The smectite is believed to have reduced the permeability of the sands so that flow was focused through other, more permeable zones, where cementation began. Interestingly, cementation continued in these relatively clay-free sands to the point that permeability was below 1 mD, much lower than for adjacent clayey sands. Presumably, favourable nucleation kinetics promoted continued cementation of the sand beyond the point of unfavourable mass transfer properties. 

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