Which of the following soil is least permeable?

Question

Question

This question was previously asked in

HSSC JE Civil 10 April 2018 Shift 1

Answer 1

Explanation:

The values and degree of permeability of various soil are tabulated below:

Soil	K (cm/sec)	Degree of Permeability
Coarse gravel	> 1	High
Fine gravel-Fine sand	1 to 10^-2	Medium
Silt sand admixtures, loose silts, rock flour and loess	10^-2 to 10^-4	Low
Dense silt, Clay silt admixtures, non-homogenous clays	10^-4 to 10^-6	Very low
Stiff Clay	< 10^-6	Impervious

Additional Information

Permeability

The permeability of soil refers to its ability to transmit water or other fluids through its pores.
Permeability is influenced by factors such as particle size, shape, and the arrangement of soil particles In a partially saturated soil (also known as unsaturated or partially saturated zone), there is a mix of air and water in the soil pores.
The presence of air in the soil can increase the permeability compared to a fully saturated soil where all the pores are filled with water.
In a fully saturated soil, the soil pores are completely filled with water, and this can lead to a decrease in permeability due to the lack of air-filled voids.
The water molecules in saturated soil tend to impede the flow of additional water.