Black cotton soil is a expansive clay type soil. The behavior of this soil has discussed in previous many posts with its molecular structure. This soil is well known in India as every year many structures settled or suffered distress of any type due to expansive potential of this soil.
In United States this scenario is almost same. We have published many post regarding foundation problem and its repair options in United States. We are providing a figure regarding distribution of vertisol (expansive soil) in North America.
This is important fact that the destruction of buildings, pipelines and roads due to this expansive soil is more than twice that from combined destruction by tornadoes, hurricanes, floods and earthquakes.
Now we are going to describe repair method for such types of destruction to a particular foundation type. Here we will discuss about slab-on-grade foundation.
At first we will have a brief idea about slab on grade foundation. Slab on grade is a foundation that is poured on grade to serve as foundation for a structure. It is sometimes used as building floor. This slab may be reinforced or unreinforced. It depends on thickness and service load of the structure. It may rest on piles or piers, grade beams or any sort of supports.
Our concern is unreinforced or insufficient reinforced slab. Slab that support on other type of deep support is not considered here. This is due to they are less susceptible to be impacted by detrimental effect of black cotton soil. To read full post please switches to part-2.