A suite of plate loading tests has recently been conducted by Sandia National Laboratories at the Exploratory Studies Facility at Yucca Mountain, Nevada. Fielding of these in situ tests as well as other approaches undertaken for the determination of rock mass modulus are described. The various methodologies are evaluated and their data compared. Calculation by existing empirical methods and numerical modeling are compared to each other as well as to field data.
Une succession de tests de plaques sous haute pression a ete conduite recemment par les Sandia National Laboratories à leur site des etudes exploratoires à Yucca Mountain, au Nevada. Cet article decrit les methodes de recherches sur le terrain ainsi que celles dues à d'autres approches utilisees pour determiner le module des masses rocheuses. Les differentes methodologies sont evaluees et leurs donnees comparees, Les calculs qui resultent de differentes methodes empiriques et d'analyses numeriques sont compares les uns aux autres ainsi qu'aux donnees rassemblees sur le terrain.
Eine Versuchsreihe von "plate loading" Tests wurde kuerzlich von den Sandia National Labs in der Exploratory Studies Facility am Yucca Mountain in Nevada durchgefuehrt. Beschrieben wird der Verlauf dieser in situ Tests als auch anderer Ansatze zur Bestimmung des Gesteinsmassenmoduls,' Die verschiedenen Methoden werden evaluiert und ihre Daten verglichen, Berechnung durch existierende empirische Methoden und numerische Modellierung werden sowohl miteinander als auch mit den experimentellen Daten verglichen.
The welded tuffs of Yucca Mountain, Nevada are being considered by the United States Department of Energy (DOE) as potential host media for the storage of high level waste (HLW). As part of the site characterization efforts for the Yucca Mountain Project (YMP), a mechanically excavated Exploratory Studies Facility (ESP) was completed in 1997. A Thermal Testing Facility (TTF), subsequently constructed off the main drift of the ESF, included the Single Heater Test (SHT) block and the Drift Scale Test (DST). The DST is being constructed in a 50-m long, 5-m diameter Heated Drift (HD). To determine potential changes in the rock mass modulus resulting from thermally induced closure of the fractures, a plate loading niche was constructed near the DST such that one side of the niche would be near ambient temperature and the other side was heated to > 100°C (Fig: 1). Determination of rock mass l modulus, a parameter of significance to the Yucca Mountain geomechanics program, is calculated using data gathered from the Plate Loading Test (PLT). It will be used in numerical analysis of drift stability, ground support interactions, and drift and repository behavior. Rock mass modulus may also be used in the coupling of the various thermal-mechanical-hydrological-chemical (T-M-H- C) models used for the proposed repository.
The PLT, conducted as part of the long-term DST, consisted of multiple elements, each unique though closely related. The elements included rock mass quality mapping, Goodman jack tests, and pre- and post-test elastic numerical predictions of the stresses and displacements within the rock mass using the actual flat jack pressurization cycles.
