Which type of foundation is best for black cotton soil?
Join TheConstructor to ask questions, answer questions, write articles, and connect with other people. When you join you get additional benefits.
Log in to TheConstructor to ask questions, answer people’s questions, write articles & connect with other people. When you join you get additional benefits.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Black cotton soil is a very dangerous soil for the building on account of its volumetric changes with the change in atmospheric conditions. It swells and shrinks according to temperature change.
When we decide on a construction in it, we have to take many precautions. Engineers prefer Pad foundation, Pier foundation, and Under-reamed pile foundation.
The under-reamed pile foundation is the best for black cotton soil. It has bulbs at its lower end.
If this bulb is given below the critical depth of moisture movement in black cotton soil, the foundation will be secured to the ground, and it would not move with movement (shrinkage and swelling) of soil.
Generally, for black cotton soil is also famous as expansive soil whose bearing capacity is less for suitability of spread footings and wall footings. So for black cotton soil mat foundation is most suitable. Mat foundation is recommended and also economical when the area of footings becomes greater than 50% area of building.
First of all if possible that we need to remove black cotton soil and make raft foundation with piles
Black cotton soil has very bad property of swelling and shrinkage due to that phenomena, different use settlement of foundation occur and lead to failure of the structure.
We can use soil treatment for foundations black cotton soil
In black cotton soil mostly used CNS material treatment and under ream foundation.
Black cotton soil swells during the rainy season and crack during the summer season due to shrinkage. If the depth of black cotton soil is more, then the following foundations may be provided.
1. Strip foundation:
These foundations are usually constructed during the dry season. A suitable plinth protection should be made around the external wall, so that moisture does not penetrate the foundation during the rainy season.
2. Pier foundation
Pier is a vertical column of a large cross-sectional area. These are taken up to good bearing strata then the piers are connected with concrete or masonry arch.
3. Under reamed pile foundation
These piles are bored and then concreted at the site. They are provided with reams and reinforcement. The top of the pile is provided with a capping beam over which walls are constructed.
The under reamed pile foundation is most commonly used in black cotton soil.
most suitable type foundation for black cotton soil is Under reamed pile
Foundation for Black Cotton Soil:
Depending on the structural needs one can choose shallow, deep as well as mat foundation. The thing that matters is which type of structure is going to be built.
Under reamed piles are best suited for black cotton soil.