Water that forms a hydration shell around soil grains is known as:

1. Structural water

The water chemically combined in the crystal structure of the mineral of the soil is called structural water.it cannot be remove without breaking the structure of the mineral.

2. Solvate water

The solvate water forms a hydration shell around soil grain. It is influenced by ionic and polar forces.

3. Pore Water

free water present in a soil. Normally under hydrostatic pressure. The shear strength of adjacent soil depends on this pore pressure, which reduces frictional resistance and soil stability

4. Infiltered water

Infiltered water is the water which infiltrate into the ground surface through pores.