Loading rate effects on sandy soils are investigated based on the results of plane strain compression tests and triaxial compression tests. Some tests are conformed at constant but different strain rates

and the strain-stress relationships are essentially independent of different constant strain rates. To evaluate the loading-rate effects on sand

the strain rate is changed stepwise many times under otherwise monotonous loading on different types of sand specimens. It is shown that

when the strain rate suddenly changes

the stress also changes sharply with a very high stiffness

nearly elastic behavior. Then

with an increase in the strain

the stress-strain curve exhibites a marked change in the tangent modulus and gradually rejoins the essentially unique one. This feature is called viscous evanescent property.