Sources of stresses in the ground
The sources of stresses at any point in the ground will be evaluated by knowing about the location, magnitude and direction of the forces that causes them at that point. These are divided in two broad categories:
The stresses which occur due to the weight of soil above the point at which we are finding stresses are known as geostatic.
These are naturally present in the ground. These can be change or altered through human activities for example through excavation and by placing a fill.
These are caused by gravity acting on the soil or rock, so the direct result is a vertical normal stress. It has a vital role in engineering behavior of the soil. This vertical normal stress then indirectly produces horizontal normal and shear stresses which are also very important.
The second main source which produces stresses in the ground are induced. The stresses caused by the external loads such as structural foundations are known as induced. These are usually produced by human activities. These loads also include vehicles, tanks, stockpiles and many others.
To find the total stress, we will find both and then add them via superposition.
The resulting induced stresses are often very important and can produce excessive settlement, shear failure and other problems.