Consolidation term is generally used in case of cohesive soil. The settlement that occur due to consolidation beneath foundation may continue several years depending on loading intensity, permeability of respective soil and drainage path available for this process.
Dear reader we are discussing here about consolidation and drainage path in this post; in our upcoming posts we will discuss how to determine total foundation settlement and time required for particular amount of consolidation.
Definition of consolidation:
when a soil layer having low permeability having certain degree of saturation is loaded to increase stress in soil mass to generate excess pore water pressure within clay layer, the soil being less permeable takes time to dissipate this pressure. Obviously this dissipation will be associated with certain volume change which leads to certain degree of settlement of soil mass. This phenomenon is termed as consolidation and respective settlement is consolidation settlement.
We will discuss about different types of settlement in our upcoming posts.
Depending on direction, nature of drainage and deformation, consolidation can be classified as:
a. One dimensional consolidation
b. Two dimensional consolidation
c. Three dimensional consolidation
a. One dimensional consolidation:
In this condition, only vertical drainage and subsequent strain occurred. This consolidation is generally happened below a load of wide extent i.e. there is no way but to drainage in vertical direction as drainage in other two horizontal directions is impossible due to
-long travel distance
-impermeability of clay deposit
Dear reader we will finish this topics in our next post where we will discuss more about one dimensional consolidation and also other two consolidation with their field example.