A review of literature concerned with time-dependent deformation of geologic and non-geologic materials is presented. A static loading machine and a four unit dynamic loading unit was designed and assembled to evaluate static and dynamic creep properties of gypsum. The tests were run for various levels of static loads, and superimposed dynamic loads. Investigations were carried out to determine the relationships, if any, between impact energy, impact velocity and momentum, and dynamic strains. Viscoelastic coefficients were determined for the investigations. The conclusion was presented that time-dependent strain in the dynamic creep tests of the particular gypsum rock tested is a function of impact momentum within the elastic limit of the material --Abstract, page ii
