Tuff rock mechanics testing in G-tunnel at Nevada Test Site

The current test activities focus on experiments which can be conducted in G-tunnel on the Nevada Test Site. G-tunnel is being used because no test facility exists at Yucca Mountain, which is being explored as a possible reposity site, and a layer of welded tuff is present in the tunnel which has thermal and mechanical properties similar to the welded tuffs at Yucca Mountain. The rock-mechanics field program was started in FY 1980 with excavation of a drift through the welded tuff stratum in G-tunnel and a subsequent geological characterization. The key activities in FY 1981 were directed toward the development of a test plan for G-tunnel field testing. A seven-task effort was defined and implemented. Tasks (2), (3), and (4) were associated with field activities in FY 1981 and are discussed in more detail in this paper. Tasks (1), (5), (6), and (7) consist of stages of experiment planning and design; resulting experiments are scheduled to be fielded in following fiscal years. These experiments are discussed in more detail as FY 1982 activities