Question

2 points on clay,sand,silt and gravel​

Answer 1

CLAYS include silty clays and clay-silts; there are few pure silts (e.g. areas formed by windblown Löess). Clay grains are usually the product of chemical weathering or rocks and soils. Clay particles have a flaky shape.

There are major differences in engineering behaviour between SANDS and CLAYS (e.g. in permeability, compressibility, shrinking/swelling potential). The shape and size of the soil grains has an important bearing on these differences. 

  

SANDS include gravelly sands and gravel-sands. Sand grains are generally broken rock particles that have been formed by physical weathering, or they are the resistant components of rocks broken down by chemical weathering. Sand grains generally have a rotund shape

Silt curtains (also called turbidity curtains, silt screens or silt barricades) are vertical barriers positioned within the water to contain the fine particles of silt that are discharged into the water from dredging, construction or reclamation activities.

Ecocoast was the first manufacturer of the full range of silt curtains in the EMEA region, under the brand Ecobarrier. The Ecobarrier Silt Curtains are manufactured in the UAE, which reduces regional shipping times and costs, and can be tailored to suit specific conditions and project requirements.

Gravel is a loose aggregation of rock fragments. Gravel is classified by particle size range and includes size classes from granule- to boulder-sized fragments. In the Udden-Wentworth scalegravel is categorized into granular gravel (2 to 4 mm or 0.079 to 0.157 in) and pebble gravel (4 to 64 mm or 0.2 to 2.5 in). ISO 14688 grades gravels as fine, medium, and coarse with ranges 2 mm to 6.3 mm to 20 mm to 63 mm. One cubic metre of gravel typically weighs about 1,800 kg (or a cubic yard weighs about 3,000 pounds).

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