Field Survey on the construction time, the heritage registration and the stability of the Longyou Caves in Zhejiang Province, China

中国，1992年在浙江龙游发现的5个大型地下洞室围岩的变质风化状态。几位当地历史学家指出，它们建于大约2300-2400年前(春秋时期)。我们需要通过岩石力学和保护学进行以下研究：1)地质调查：除了地形和地质调查外，还应用了电法勘探(电阻率法)。详细调查了地质构造、洞口结构、断层和裂隙2)地下洞口的尺寸：而不是传统的激光经纬仪，后者被认为需要非常长的时间。调查中，使用了最新的3D-Scanner系统。在一周内测量了四个孔洞的精确尺寸。3)岩石的物理性质：从岩石表面和TH…取样并从颗粒分布、崩解性、矿物组成、差热行为、比表面积、孔径、盐化和生物风化效应等方面进行了分析。得出结论：粘土矿物的膨胀压力和溶解度是风化过程中的主要原因，氢离子浓度的变化可以很好地反映洞穴的特征。4)洞穴环境监测：连续测量了两年多的温度、相对湿度、照度和气压。建立了地下洞室环境数据库。从这次调查和各个洞口上方地面的电阻率分布来看，我们建议当地政府(负责保护洞口)拆除几个本应招待游客的人造水库。水库渗漏水显著加速了风化破坏。5)沉积物分析：确定洞口的施工时间是关键。由于习俗规定，不允许运输从洞口底部取样的人造沉积物。总之，我们发现，电阻率法、3D激光扫描和氢离子分析的应用提供了非常丰富的信息，成功地通过非破坏性方法、调查和综合信息建立了调查有价值的遗址的新途径。较少

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 … More 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