Scientific Site Selection of Ancient Large-scale Underground Quarries from Engineering Geology: A Case of Shepan Island in Sanmen, China

There are many ancient underground quarries in Zhejiang Province, China. Many caverns of them maintained steady more than 1000 years. Certain engineering geological condition is very important for long-term stability. In this paper, ancient underground quarries in Shepan Island are presented as a case. Shepan Island ancient large-scale underground quarry caverns are located in Sanmen County, Zhejiang Province. These caverns were excavated more than 800 years ago and at least 1300 of them are reserved until now. Shepan Island is a hill which uplifts the continental shelf extending to the gulf. There are no large regional fractures through caverns area, which indicates that it belongs to earthquake stability region. The caverns were excavated in thick volcanic clastic rock formed in the upper Jurassic, with NW and NE faults and NW joints. Based on the study of rock weathering, physical and mechanical tests of rock samples, and inverse analysis of structural plane, the huge thick volcano clastic rock can be classified as block structure. In addition, groundwater which affects the stability of caverns was analyzed based on the investigations of hydrogeological conditions. Site selection of ancient large-scale underground quarries is query scientific from modern engineering geology point of view.