Ground Control for Emplacement Drifts for SR

Sun, Y.

United States. Department of Energy. Yucca Mountain Project Office.

关键词: Strata Control;    12 Management Of Radioactive Wastes, And Non-Radioactive Wastes From Nuclear Facilities;    Classification;    Excavation;    Positioning;   

DOI  :  10.2172/759646
RP-ID  :  ANL-EBS-GE-000002, REV 00
RP-ID  :  AC08-91RW00134
RP-ID  :  759646

美国|英语

来源: UNT Digital Library

【 摘 要 】

This analysis demonstrates that a satisfactory ground control system can be designed for the Yucca Mountain site, and provides the technical basis for the design of ground support systems to be used in repository emplacement and non-emplacement drifts. The repository ground support design was based on analytical methods using acquired computer codes, and focused on the final support systems. A literature review of case histories, including the lessons learned from the design and construction of the ESF, the studies on the seismic damages of underground openings, and the use of rock mass classification systems in the ground support design, was conducted (Sections 6.3.4 and 6.4). This review provided some basis for determining the inputs and methodologies used in this analysis. Stability of the supported and unsupported emplacement and non-emplacement drifts was evaluated in this analysis. The excavation effects (i.e., state of the stress change due to excavation), thermal effects (i.e., due to heat output from waste packages), and seismic effects (i.e., from potential earthquake events) were evaluated, and stress controlled modes of failure were examined for two in situ stress conditions (k_0=0.3 and 1.0) using rock properties representing rock mass categories of 1 and 5. Variation of rock mass units such as the non-lithophysal (Tptpmn) and lithophysal (Tptpll) was considered in the analysis. The focus was on the non-lithophysal unit because this unit appears to be relatively weaker and has much smaller joint spacing. Therefore, the drift stability and ground support needs were considered to be controlled by the design for this rock unit. The ground support systems for both emplacement and non-emplacement drifts were incorporated into the models to assess their performance under in situ, thermal, and seismic loading conditions. Both continuum and discontinuum modeling approaches were employed in the analyses of the rock mass behavior and in the evaluation of the stability of the openings. No credit or account was given for the initial ground support in modeling the final ground support systems for both emplacement and non-emplacement drifts in this analysis.