Wave Propagation in Intact and Jointed Calcium Carbonate (CaCO3) Rock.
Technical rept. 5 Aug 92-30 Apr 95,
SRI INTERNATIONAL MENLO PARK CA POULTER LAB
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In support of the Defense Nuclear Agencys HYDRO PLUS program, SRI performed a series of uniaxial strain experiments using in-contact explosive techniques to investigate the effects of in situ and artificial joints on wave propagation in calcium carbonate CaCO3 rock. The in situ joints investigated were healed, calcite filled fissures in a nonporous limestone matrix. These joints did not have a significant effect on the observed response. On the other hand, artificial, sand filled joints in marble caused an increase in the peak particle velocity upstream from the joint and a delayed time of arrival TOA of the wave at the gage downstream from the joint. Both peak particle velocity and TOA are used within the framework of the HYDRO PLUS yield estimation methodology. A spherical wave experiment was also conducted on a sample of intact Danby marble to complement the uniaxial strain experiments and to provide data that can be used to validate andor calibrate constitutive models for use in finite element and finite difference hydrocodes. The results of this experiment indicate that the occurrence of cracking can have a significant effect on the observed response if measurements are made in the strength dominated region.