This paper

comparing the dynamic test results of mudstone (silty clay) with the static ones

verifies influence of cyclic loading and loading rates on the strength of mudstone. It is found that the dynamic strength is higher than the static strength. In the case of rapid loading (rising time of pressure is 10ms )

the unconfined compressive strength for this type of soil in dynamic test is 2.3 to 2.9 times as high as that in static tests

and the strength index

Cd

is about 2.8 times as great as Cs

but ∅ values are approximately equal to each other. Repeat loading (up to 3600 cycles) has no great influence on the strength of mudstone

and under the condition of unconfined loading

the fatigue strength of mudstone is somewhat lower than its statically strength.