Black Cotton Soil

◆Black cotton soil◆

👉 It is also known as Regur or Maan

👉variable thickness which is underlain by a sticky material called shadu or khalaga.

👉Type of Residual soil.

👉 Volcanic origin.

👉highly expansive, sticky and plastic clays showing high swelling and shrinkage.

👉Montmorillonite is the predominant present in BC soil.

👉pH value- 8.9(Alkaline)

👉Sp. Gr- 2.6-2.75

👉Activity- 0.8-1.5

👉Compression index- 0.2-0.5

👉CBR(Soaked) - 1.2-4

👉Shear parameters-
Cu=10-80Kn/m²
¢=5°-15°

👉Black color due to
1.Humus
2.Titanium Oxide.

👉Expansiveness can be found out by using
1.Russian method
2.Free swell test
3.Differential Free swell Test(IS 2911 part3)
4.Swelling pressure test


👉Minimum depth of foundation-
2 to 3 m

👉Suitable foundation-
1.Short Bored Piles
2.Under-reamed piles

💥💥  @civilbhai  💥💥