Due to dynamic compaction, the structure of loess is changed and by increasing the number of dynamic blows, the soil is involved in axial deformation. This deformation iis done as collapse and strain. To 6 blows, the axial strain rate is more and other that it is decreased to achieve a constant rate. Generally, due to the blows, crack, grains bending, the torsion of grainsa, the break of grains, crush of peds and grains compaction are occurred. The serverity, type and amonut of soil strain depend upon the number of blows and the type of soil. In loess of Golestan, three different behavior is seen. The loess collapsing due to the structure blow. The other group in which axial deformation is created and the other group show the collapse and axial deformation.

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