Stability Of Large-Scale Rock Cavern Complex At The 800-Year Feifengyan Quarry

This paper deals with long-term stability of an ancient large underground rock cavern complex excavated some 800 years ago in Zhejiang Province, SE China. The rock cavern complex is characterized by complicated geometric aligns, unique structure designs, large spans with shallow depths. Its rock mass characteristics were firstly investigated and the favorable rock mass quality was verified using the collected in-situ data. Distinctive quarrying method-Digging Holes for Quarrying Vertical Flagstone (DQF) was introduced the ancients to ensure safe excavation, it proved much smarter than modern blast-casting method. The favorable rock mass quality, smart structure designs, and ingenious quarrying technique were concluded to collectively lead to the noticeable long-term stability of the cavern complex. These ancient achievements mark high level of quarrying in complicated geo-environments with manpower, the results are positive to extend our knowledge in category design of cavern scale and stability assessments.