Dear reader in our last post we have learnt how dry density of soil is related to water content in compaction process. Here we will discuss this phenomenon in light of electric double layer theory and soil structure. Lambe in 1958 provided this relation as discussed below.
At first we will discuss about adsorbed water as it is related to this discussion. We know in some soil surface, there have electro-chemical charges which can hold water. This electro-chemically bond water is adsorbed water. As electrical force act on this water, the behavior of adsorbed water is quite different from normal water.
Plasticity of cohesive soil is due to this adsorbed water. Dear reader in our upcoming post we will learn in details about adsorbed water. Here we want to co-relate its influence on changes in dry density.
In this part we simply explain the phenomena like – the attraction forces in layer of adsorbed water are large when water content is low and produce more resistance against movement of soil particles thus wasting compacting effort.
When water content in soil mass in increased, the repulsive forces remain in particles are increased to allow sliding over one another and finally lead to closely packed condition.
We think you are not satisfied with this explanation, to know how do actually repulsive force developed please read next part, will be published consecutively.