We know about the soil type clay and plastic silt. Normally we differentiate them depending on particle size. Here we will discuss about normally loaded clay and plastic silts and their similarity in foundation design assumptions. We have discussed about plastic clay and piling difficulties in plastic clay. Dear reader here we will used the term normally loaded clay.
This loading condition prevails in our particular stratum of interest. A stratum may be termed as normally loaded or preloaded. The preloaded clay is well known as over consolidated clay. But our concern is normally loaded clay; so we are discussing this term now. A stratum is in normally loaded when this is not subjected vertical pressure in its history greater than existing pressure; at the time of investigation. Dear reader we will discuss all related terms of different loading conditions and necessary derivation in our upcoming posts.
The plasticity in silts may arise from significant percent of organic content or from plate-shaped particles of appreciably high percentage. A deep deposition of silts having more or fair amount organic content is generally found in following location or regions:
Near the shores of oceans or lakes. From former or present shore, this deposition is found.
In the river beds. The river may be still flowing or it may be an ancient one.
These silts do not always perform as normally loaded clay. The situations when they act like this form of clay are:
The deposition should remain below water table
Have never cha
nce to be exposed and subsequent drying.