アンコール・ワットを構成する砂岩およびラテライトの風化環境と風化プロセス

概要

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Weathering environment at two study sites of Angkor Wat were analysed together with mineralogical and physico-chemical behaviour of building stones of sandstone and laterite. In order to store the set of data of air temperature and relative humidity at intervals of 30 minutes, two data loggers were installed at Elephant gate (Site 1) and West causeway (Site 2), between 5 September 2000 and 10 September 2001. The results show that Site 1 had more severe temperature and humidity changes (-5℃/30min, 24%/30min in maximum) than Site 2 (-4℃/30min, 19%/30min). In addition, Site 1 had a high frequency of wetting and drying cycles (73 cycles) compared to Site 2 (6 cycles). These measurements argue that wet-dry alternation and salt efflorescence are major in exfoliation on sandstone surfaces at Elephant gate. The laterite composed of goethite, hematite, quartz and kaolinite has no swelling clay minerals. However, the laterite has small tensile strength (1.2 MPa) than the sandstone (3.5 MPa), as well as low durability for wet-dry repetition. It is recognized that slaking of the laterite due to fluctuation in water level at the moat has caused subsidence of West causeway.
日本地形学連合の論文
2005-07-25