Choose the correct answer. Also, justify the answer with reasonable explanation.
ID: 1710995 • Letter: C
Question
Choose the correct answer. Also, justify the answer with reasonable explanation. The submerged density of soil, rho_sub is always less than the density of water. The dry density of a soil can be determined using the expression below: rho_d = G_s rho_w/1 + w G_s/S where: G_s = specific gravity, rho_w = density of water, w = water content, S = degree of saturation The maximum value of liquid limit, w_L for any soil is 100%. The saturated coefficient of permeability of silty sand is typically greater than that of a sandy silt. The plasticity index, I_p of typical expansive clay is greater than that of sandy silt. The effective cohesion of over-consolidated sample measured in the laboratory using triaxial tests is typically close to zero. The vane shear test apparatus is the most reliable equipment for determining the effective shear strength parameters, c', and phi' of a soft saturated clay. A clayey soil with the mineral montmorrilonite has a lower coefficient of permeability in comparison to clays that have kaolinite or illite as clay minerals. The dry density of an sandy silt at its optimum moisture content is higher than the dry density of a clay at its optimum moisture content A uniformly graded soil has a good and equal representation of all particle sizes from the largest to smallest size of that particular group Both the triaxial test and the direct shear test equipment can be used to determine the effective shear strength parameters (c' and phi') of sands as well as clays under drained loading conditions (i.e., CD tests) The angle of internal friction of clayey soil (phi) measured from consolidated undrained conditions (without measuring the pore-water pressures) is always greater than the angle of internal friction (phi') for the same, measured under consolidated drained conditions. In some organic soils, secondary compression settlement can be greater than the primary consolidation settlement.Explanation / Answer
1. true
Submerged Density of soil (kN/m3) = Saturated Density- Water Density
Water Density= Saturated Density+Submerged Density of soil (kN/m3)
from above relation, submerged density of soil is less than water density
2.false
because for degree of saturation for dry soils must be be zero( s=0)
the degree of saturation has been innvoled in the equation
hence given statement is wrong
3. true
Liquid limit is defined as “ the moisture content at which soil changes from liquid state to plastic state”
if 100% of water content of water has been been added to the soil then soil must changes from liquid state to plastic state for any type of soils
4. typo error
generally, coefficient of permeability value is propotional to void ratio (e)
sandy silt,sity sand both are same