This paper presents the relics of rock joints caulked with lead strips, unearthed by the authors in 2007 and 2008. The relics were in ancient quarry caverns in Shepan Island, Zhejiang Province, eastern China. The quarry activities were mainly carried out for production of regular tuff stone plates about 800 years ago. Each of the lead strips was sealed into a rock joint by punching manually and carefully. At present, the lead strips still contact tightly with the rock joints and new mineral cerussite is found to have formed at the contact surfaces between the lead strip and its caulked rock joint. The use of lead strips caulking rock joints in quarry caverns is found for prevention of water from seeping out of the country rocks into quarry cavern bases, where all of the in-situ intact tuff rock was manually and near-horizontally split into thin rock sheets one by one for production of regular tuff plates. Furthermore, it is found that the tensile splitting of tuff sheets at the cavern base required the intact rocks at the cavern base had to be dry. Through this horizontal base splitting for tuff sheets from the top to the bottom, a dome-shape interior space was formed for each rock cavern with the near horizontal imprints of thin sheet layers permanently on the sidewalls.
YANG ZhiFaZHANG LuQingYUE ZhongQiZHANG ZhongJianYANG TianYaoLIN XianJianTAO KeJieZHU JieWang
This paper presents a comprehensive summary of data, analyses and findings from the investigations over the past twelve years about the relics of large Longyou rock caverns carved about 2 000 years ago at shallow depths in argillaceous siltstone. The paper presents the typical features associated with the rock caverns. They include structures, large spans, portals, extreme shallow-buried depths, imprints, drainages, inclined ceiling, inclined sidewalls, slender rock pillars, rock staircases, site and strata selections, caving lighting, carving method, and underground construction surveying. They are used to reconstruct and highlight the design and construction methods adopted by the ancients. The paper further demonstrates that the relics of the complete large rock caverns are a consequence of coincidental combinations of ancient human effort and natural factors. The full occupation of water with weak acidity in the large rock caverns with the soft surrounding rocks of weak alkalinity is found to be the main factor ensuring and preserving the caverns to have been stable and integral over 2 000 years. However, the five unwatered complete rock cavern relics have been experiencing various deteriorations and small failures including cracks, seepage, small rock falls and delaminating ceiling rocks. Although these deteriorations have been repaired and stabilized effectively, the paper demonstrates that an entire roof collapse failure is highly possible in the near future to each of the five unwatered rock cavern relics. The findings presented in this paper are also invaluable both to the long-term protection and preservation of the large rock cavern relics of national and international interests and importance, and to extend and enrich our experience and knowledge on the long-term stability and integrity of man-made underground rock cavern engineering projects.
Zhifa Yang1, Zhongqi Yue2, Lihui Li1 1 Key Laboratory of Engineering Geomechanics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China 2 Department of Civil Engineering, the University of Hong Kong, Hong Kong, China
