Complex sentence: Therefore, it is really important to use such physically based models to promote our understanding of the mechanics of the soils and that is why it can be of great help for researchers in the area of unsaturated soil mechanics.
Split into simpler sentences: Therefore, it is really important to use such physically based models to promote our understanding of the mechanics of the soils. That is why it can be of great help for researchers in the area of unsaturated soil mechanics.