| Co-Investigator(Kenkyū-buntansha) |
KOIZUMI Keigo Osaka University, Global Architecture, Assistant, 大学院工学研究科, 助手 (10362667)
IMAI Katsuhiko Osaka University, Global Architecture, Professor, 大学院工学研究科, 教授 (30301253)
TACHIBANA Eizaburo Osaka University, Global Architecture, Professor, 大学院工学研究科, 教授 (80029165)
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| Research Abstract |
The objective of this research is to clarify a state of deterioration and weathering of rock, surrounding the five huge underground openings which were found in Longyou, Zhejiang Province, China, 1992. Several local historians pointed out that they were constructed approximately 2,300-2,400 years ago (the Spring-and-Autumn Period). We needed to study through rock mechanics and conservation science as follows:1) Geological survey: In addition to topography and geological surveys, the electric prospecting (Electric Resistivity Method) was applied. The geological formations, structure of the openings, faults and fissures were investigated in detail.2) Dimensions of the underground openings: Instead of a conventional laser transit, which was considered to require a tremendously long time for. survey, the latest 3D-Scanner system was employed. The precise dimensions of four openings were measured in one week.3) Physical properties of rock: Rock specimens were sampled from the surface and th
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e wall of openings, and analyzed from the points of view on particle distribution, slakability, mineral components, differential thermal behavior, specific surface area, pore size, salinization and biological weathering effect. We concluded that swelling pressure and solubility of clay minerals are main causes in weathering process, and a change of hydrogen ion concentration can be a good indicator for characterization.4) Environmental monitoring in caves: Temperature, relative humidity, illuminance, and barometric pressure have been measured continuously over two years. We establish the data base for the environment of the underground opening. from this survey and the distribution of electric resistivity in the ground above the respective openings we suggested the local government (charged in preserving the openings) to remove several man-made reservoirs which were supposed to entertain visitors. The seeping water from the reservoirs remarkably accelerated weathering damage.5) Analysis of sediments: it was the key issue for us to identify a construction time of the openings. Due to the custom regulations it was not allowed to transport the mad sediments which had been sampled from the bottoms of the openings.
Above all, we found that the application of the Electric Resistivity Method, the 3D Laser Scanning, and the hydrogen ion analysis were very informative, and it was successful to establish the new access to investigate valuable heritage sites through the non-destructive methods, surveys, and integrated information. Less
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