ELECTRICAL IMAGING AT THE LARGE BLOCK TEST YUCCA MOUNTAIN, NEVADA

Ramirez, A.

United States. Department of Energy. Office of Scientific and Technical Information.

关键词: Heating;    Fractures;    Drying;    Heaters;    Water;   

DOI  :  10.2172/860275
RP-ID  :  UCRL-JC-140906
RP-ID  :  NA
RP-ID  :  860275

美国|英语

来源: UNT Digital Library

【 摘 要 】

A monolithic block of densely welded tuff was excavated from a site on Fran Ridge near Yucca Mountain, Nevada so that coupled thermohydrological processes could be studied in a controlled, in situ experiment. A series of heaters were placed in a horizontal plane about 3 m from the top of the 3 m by 3 m by 4.5 m high block. Temperatures were measured at many points within and on the block surface and a suite of other measurements were taken to define the thermal and hydrologic response. Electrical resistance tomography (ERT) was used to map 2 dimensional images of moisture content changes along four planes in the block. The ERT images clearly delineate the drying and wetting of the rockmass during the 13 months of heating and subsequent six months of cool down. The main feature is a prominent dry zone that forms around the heaters then gradually disappears as the rock cools down. Other features include linear anomalies of decreasing moisture content which are fractures dehydrating as the block heats up. There are also examples of compact anomalies of wetting. Some of these appear to be water accumulation in fractures which are draining condensate from the block. Others may be rain water entering a fracture at the top of the block. During cooldown a general rewetting is observed although this is less certain because of poor data quality during this stage of the experiment.