Mechanical and bulk properties in support of ESF design issues

An intensive laboratory investigation is determining the mechanical properties of tuffs for the Yucca Mountain Site Characterization Project (YMP). Most recently, experiments have been performed on tuff samples from a series of drill holes along the proposed alignment of the Exploratory Study Facilities (ESF) north ramp. Unconfined compression and indirect tension experiments were performed and the results are being analyzed with the help of bulk property information. The results on samples from five of the drill holes are presented here. In general, the properties vary widely, but are highly dependent on the sample porosity