Drift design methodology and preliminary application for the Yucca Mountain Site Characterization Project; Yucca Mountain Site Characterization Project

Hardy, Michael; Bauer, Stephen J.

doi:10.2172/138270

Cited by 11 publications

(37 citation statements)

References 13 publications

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“…However, for Q values less than 1, the Main Drift data often exceed the upper 90% confidence limit. Hardy and Bauer (1991) attributed this effect to the fact that the stress/strength term (SRF) in the Q system accounts for structural effects similar to the RQD, while the strength index in the RMR system remains fairly constant for a particular rock type. The procedure for calculating RMR for the ESF tunnels is less sensitive to joint conditions when compared to the Q system.…”

Section: Correlation Of Q and Rmr Resultsmentioning

confidence: 99%

“…Rock mass mechanical properties have been estimated for the Tptpmn based on the methodology proposed by Hardy and Bauer (1991) using published empirical correlations with RMR. Estimated rock mass strength for each of the five cumulative frequencies of occurrence (5%, 20%, 40%, 70%, and 90%) of RMR data is compared to intact rock strength in Table 2 Ground Support Category …”

Section: Rock Mass Mechanical Properties Estimatesmentioning

confidence: 99%

“…A site-specific rock mass strength criteria has been developed following the procedure of Hardy and Bauer (1991) using both the Hoek and Brown (1988) and Yudhbir et al (1983) strength criteria. The data needed for using this approach include the rock mass quality index RMR, intact rock uniaxial compressive strength, and triaxial compressive strength data.…”

Section: Rock Mass Strengthsmentioning

confidence: 99%

“…The strength parameters were developed from a linear fit of strength data pairs (cr,, a 3 ) used to produce the strength envelopes in Figure 6 Table 6-3. The non-associated flow rule suggested by Michelis and Brown (1986), which uses a dilation angle equal to half the internal friction angle, was considered suitable for the tuff rocks of the ESF (Hardy and Bauer 1991) and the resulting values for dilation angles are also listed in Table 6-3. The intact Mohr-Coulomb strength parameters (Section 4.2) are listed in Table 6-3 for comparison to the rock mass values.…”

Section: Rock Mass Mohr-coulomb Strength Parameters and Dilation Anglesmentioning

confidence: 99%

“…The rock mass mechanical properties of interest included rock mass strength, the elastic modulus, and the Poisson's ratio. Hardy and Bauer (1991) have recommended rock mass strength criteria and mechanical models for representing the rock mass response of the tuff at Yucca Mountain. Empirical methods are used with RMR data and the laboratory rock mechanical properties to estimate the rock mass mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

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Geotechnical characterization for the Main Drift of the Exploratory Studies Facility

Kicker¹,

Martin²,

Brechtel³

et al. 1997

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Geotechnical Characterization of the Main Drift of the Exploratory Studies Facility was based on borehole data collected in site characterization drilling and on scanline rock mass quality data collected during the excavation of the North Ramp. The Main Drift is the planned 3,131-m (10,273-ft) near-horizontal tunnel to be excavated at the potential repository horizon for the Yucca Mountain Site Characterization Project. Main Drift borehole data consisted of three holes -USW SD-7, SD-9, and SD-12-drilled along the tunnel alignment. In addition, boreholes USW UZ-14, NRG-6, and NRG-7/7A were used to supplement the database on subsurface rock conditions. Specific data summarized and presented included lithologic and rock structure core logs, rock mechanics laboratory testing, and rock mass quality indices. Cross sections with stratigraphic and thermal-mechanical units were also presented. Topics discussed in the report include geologic setting, geologic features of engineering and construction significance, anticipated ground conditions, and the range of required ground support.Rock structural and rock mass quality data have been developed for each 3-m (10-ft) interval of core in the middle nonlithophysal stratigraphic zone of the Topopah Spring Tuff Formation. The distribution of the rock mass quality data in all boreholes used to characterize the Main Drift was assumed to be representative of the variability of the rock mass conditions to be encountered in the Main Drift. Observations in the North Ramp tunnel have been used to project conditions in the lower lithophysal zone and in fault zones. DISTRIBUTION O^ TWIS r>or,UMENT IS UNLIMITED^

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Section: Correlation Of Q and Rmr Resultsmentioning

confidence: 99%

Section: Rock Mass Mechanical Properties Estimatesmentioning

confidence: 99%

Section: Rock Mass Strengthsmentioning

confidence: 99%

Section: Rock Mass Mohr-coulomb Strength Parameters and Dilation Anglesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geotechnical characterization for the Main Drift of the Exploratory Studies Facility

Kicker¹,

Martin²,

Brechtel³

et al. 1997

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Multiphysics processes in partially saturated fractured rock: Experiments and models from Yucca Mountain

Rutqvist

Tsang

2012

Reviews of Geophysics

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The site investigations at Yucca Mountain, Nevada, have provided us with an outstanding data set, one that has significantly advanced our knowledge of multiphysics processes in partially saturated fractured geological media. Such advancement was made possible, foremost, by substantial investments in multiyear field experiments that enabled the study of thermally driven multiphysics and testing of numerical models at a large spatial scale. The development of coupled‐process models within the project have resulted in a number of new, advanced multiphysics numerical models that are today applied over a wide range of geoscientific research and geoengineering applications. Using such models, the potential impact of thermal‐hydrological‐mechanical (THM) multiphysics processes over the long‐term (e.g., 10,000 years) could be predicted and bounded with some degree of confidence. The fact that the rock mass at Yucca Mountain is intensively fractured enabled continuum models to be used, although discontinuum models were also applied and are better suited for analyzing some issues, especially those related to predictions of rockfall within open excavations. The work showed that in situ tests (rather than small‐scale laboratory experiments alone) are essential for determining appropriate input parameters for multiphysics models of fractured rocks, especially related to parameters defining how permeability might evolve under changing stress and temperature. A significant laboratory test program at Yucca Mountain also made important contributions to the field of rock mechanics, showing a unique relation between porosity and mechanical properties, a time dependency of strength that is significant for long‐term excavation stability, a decreasing rock strength with sample size using very large core experiments, and a strong temperature dependency of the thermal expansion coefficient for temperatures up to 200°C. The analysis of in situ heater experiments showed that fracture closure/opening caused by changes in normal stress across fractures was the dominant mechanism for thermally induced changes in intrinsic fracture permeability during rock mass heating/cooling and that fracture shear dilation appears to be less significant. Significant effort was devoted to predicting the long‐term stability of underground excavations under (mechanical) strength degradation and seismic loading, perhaps one of the most challenging tasks within the project. We note that such long‐term strength degradation is actually an example of a chemically mediated process governed by underlying (microscopic) stress corrosion and chemical diffusion processes. In the Yucca Mountain Project, such chemically mediated mechanical changes were considered implicitly through model calibrations against laboratory and in situ heater experiments at temperatures anticipated to be experienced by the rock. A possible future research direction would be to simulate such processes mechanistically in a complete coupled THMC framework where C denotes chemical processes.

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Progress report on the scientific investigation program for the Nevada Yucca Mountain Site, October 1, 1991--March 31, 1992, Number 6

1992

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Drift design methodology and preliminary application for the Yucca Mountain Site Characterization Project; Yucca Mountain Site Characterization Project

Cited by 11 publications

References 13 publications

Geotechnical characterization for the Main Drift of the Exploratory Studies Facility

Geotechnical characterization for the Main Drift of the Exploratory Studies Facility

Multiphysics processes in partially saturated fractured rock: Experiments and models from Yucca Mountain

Progress report on the scientific investigation program for the Nevada Yucca Mountain Site, October 1, 1991--March 31, 1992, Number 6

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