These are special soil deposits that may impart serious problem to our foundation. These soil deposits include:
- Loess and collapsible soil
- Expansive soil
- Organic soils and peat
- Colluvium and Talus
- Shale and degradable materials
- Cemented sands
- Sensitive clays
- Partially saturated soils
We have discussed many terms of collapsible soils and expansive soils in our blogs. We have already discussed mineral structures of expansive soil like black cotton soils. Black cotton soils are a big problem in foundation work in India, Africa, and United States; though the local name may differ but the soils are of same nature.
The foundation problems will be discussed in terms of engineering properties. Other soils are relatively new topics in our blogs. We will discuss elaborately about identification method, sampling and also sampling difficulties in our blogs.
This type of soil, subjected to collapse of irrecoverable amount under inundation; they are generally erodible. The weakness under contact of water, seeks conscious investigation of soil and foundation engineers have to pay special attention to this soil. This soil should be investigated for material properties at desired moisture content.
This type of soil is enriched with clay particles. But this soil suffers volume changes of recoverable range. The volume changes may be swelling and shrinkage with the variation of moisture content cases, this soil is avoided by not shifting the site but removing shallow layer of expansive soil. Usually a sand cushion is provided below foundation. Though the mechanism of this provision is unknown, this techniques works with some limitation.
In some cases where removing of deep layers of expansive soil is not practical or economical, some types of anchoring system like anchored pile or under-reamed pile foundation is used. We have published numerous posts about foundation problems and possible remedies to get out of these problems. You are invited to read these posts; please follow the link below:
Dear reader in the next post we will learn about foundation problems with organic soils. In most cases for such soils, the project is relocated in many mega projects of the world. We will learn about this in the next posts.