# Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

Discussion Forum : Soil Mechanics and Foundation Engineering - Section 1 (Q.No. 5)
5.
Which one of the following statements is true ?
Clays are more porous than sands
Pressure of organic matter in a soil decreases the bearing capacity of the soil
Aluminous cement is used for foundations in soils with chemical deposits
All the above.
Explanation:
No answer description is available. Let's discuss.
Discussion:
57 comments Page 6 of 6.

Yaregal said:   9 years ago
Pore size and it's connectivity determines the porosity of the soil. It is possible to have almost zero permeability for large spacing.

Bob Rat said:   10 years ago
Porosity and permeability are directly proportional. As your porosity increases, so does your permeability. Porosity is related mathematically to your void space as porosity, let's call it p, p = v_v/v_t where v_v is volume of voids and v_t is volume total.

If your void space is increased then the ability for water to flow through is also increased because there is more space for fluid to flow naturally. Therefore, Biswas's confusion above is legitimate. This question is improperly worded.

Vk kushvaha said:   10 years ago
Porosity is inversely proportional of permeability.

That is porosity of clay >silt >sand > gravel.

Where as permeability is gravel >sand >silt> clay.

Water easily pass through sand, but not incase of clay. So how option A is right?

Chandan ku said:   1 decade ago
How many type of cement used in construction?

Mayuri patil said:   1 decade ago
Porosity of clay is 33-60%.

And porosity of sand is 20-35%.

Hence clay is more porous than sand.