Cyclic Interface and Joint Shear Device Including Pore Pressure Effects

An understanding of the mechanical behavior of saturated interfaces between structural and geologic materials and joints in rock, subjected to cyclic earthquake-type loading, is important for safe and improved analysis and design of many geotechnical structures. Appropriate testing is vital for the determination of parameters in constitutive models to characterize the mechanical response in terms of stress-strain and failure behavior. The cyclic multi–degree-of-freedom (CYMDOF-P) testing device described here is new and unique in the sense that it allows integration of a number of important factors—such as pore-water pressures, direct and simple shear deformations, drained and undrained conditions, and static and cyclic loading—that were not available in previous devices. Typical laboratory test results to show the validity of the device, and brief statement of unified constitutive models that can be developed based on the test data are presented.