. The other two are Mogao Grottoes in Dunhuang, Gansu province, and Longmen Grottoes in Luoyang, Henan province. As for Yungang, after the royals left the city, more caves were constructed under the support of lower-ranked nobles, officials, and civilians, which are much smaller. The Yungang Grottoes Site is one of the three top cave clusters in China constructed in the Wei Kingdom era and inscribed on the UNESCO World Heritage List. Based on the above analysis, there were cementing materials dominated by feldspar minerals around the quartz particles. Yungang Grottoes | govt.chinadaily.com.cn It was created by Huangfu Du, uncle of Empress Hu. This result is consistent with that of [3], but it is different from the earlier findings of [22, 23]. Experts and skilled workers applying scientific methods to protect treasure trove of Buddhist art. The Sakyamuni statue is representative of the Buddha sculptures of the Yungang Grottoes. The mechanism of weathering for the salt-rock interaction included salt crystallization in the pores or fissures and chemical reactions between the minerals (such as feldspar and calcite) and sulfate, in addition to the above three effects. (b) Group B. The site stretches about 1 kilometer from east to west and was hollowed from the sandstone cliffs of the Wuzhou Mountains during the 5th century CE under the patronage of the Northern Wei dynasty. Yao et al. He has been engaged in the repair of relics in Yungang for more than 10 years. Yungang Grottoes saved for the nation and people to enjoy for years to The structure of the feldspar sandstone changed under dry-wet cycles; that is, structural damage was generated. The stress-strain characteristics of the feldspar sandstone essentially reflected the damage caused by the dry-wet cycles with a salt solution. The matrix included feldspar, clay, and the pore and fissure structure. Buddhist Statues and Reliefs in Cave of the Yungang, Photo by Dongmaiying. 11, no. The conclusion drawn from surface roughness analysis is essentially the same as the variation pattern of the macroscopic mechanical properties. The weathering mechanism of the salt-rock interaction included, in addition to the above three effects, salt crystallization in the pores or fissures and the chemical reaction between the minerals (e.g., feldspar and calcite) and sulfate. Address: southern foot of the Wuzhou Mountain, 16 km west of Datong city, Shanxi province. Before the test, the feldspar sandstone fragments were ground into powder (less than 200 mesh) in an agate mortar. This work was supported by the National Key R&D Plan of China (Grant no. The biggest Buddha, a seated statue 56 feet tall, has a thin layer of gold paint on its face. Early Humans Were Weaving Baskets in the Philippines 40,000 Years Ago! Additionally, the above phenomena indicated a higher degree of damage than that corresponding to the dry-wet cycles with water. The feldspar sandstone was scanned with a Hitachi S-3400N scanning electron microscope (SEM) to determine its apparent morphology and microstructure. 192, pp. It can be seen from Figure 7(a) that the uniaxial loading of the feldspar sandstone after the dry-wet cycles with water-rock interaction generally show a trend of first increasing and then decreasing, and the curve has a notable compaction stage and destruction stage. All data used in this article are available from the corresponding author by request. JavaScript is disabled for your browser. History Cave 9 After the decline of the West Jin dynasty, the northern parts of China came under the control of the Tuoba -ruled Northern Wei. Datong Yungang Grottoes - TravelChinaGuide The dry-wet cycle test was conducted in reference to the requirements of the free immersion method in the specification (GB/T50266-99). See all things to do Yungang Grottoes 4.5 974 reviews #1 of 63 things to do in Datong Historic Sites Ancient Ruins Caverns & Caves Closed now 8:30 AM - 5:20 PM Visit website Email Write a review About There are over 50 caves with over 50,000 well-preserved Buddhist statues from the 5th century. Therefore, the dry-wet cycle could promote the expansion of pores and fissures in the feldspar sandstone, and the salt-rock interaction was more pronounced than the water-rock interaction. Travelers are able to take a fascinating insight into China's . All rights reserved. 31, pp. It can be seen that as the number of dry-wet cycles increased from 0 to 25 for the Group A samples, the compressive strength decreased from 27.14MPa to 13.97MPa with a reduction of 48.53%, and the elastic modulus decreased from 981MPa to 720MPa with a reduction of 26.61%. UNESCO The Yungang Grottoes are some of the best examples of ancient Chinese Buddhist rock-cut architecture. Built in 366, the Mogao Grottoes are located in Dunhuang at the western end of the Hexi Corridor, while the Maijishan Grottoes were built in 384 in Tianshui, at the eastern end of the corridor. The brittle property of the feldspar sandstone still existed even after multiple dry-wet cycles. Inside the entrance to the Yungang Temple is an impressive four-storied wooden fa?ade with a glazed top outside Caves 3, 4 and 5. 4, pp. This complex with 52 large and a lot more small caves has been on the UNESCO World Heritage List since 2001. Because ultrasonic waves have different propagation velocities in different media, longitudinal wave velocity can characterize the development of the internal pores or fissures of rock. There have been numerous studies on the physical and mechanical properties of feldspar sandstone and ordinary sandstone, such as those above-mentioned [913]. 6467, 2004, in Chinese. Microscopic process of the salt-rock dry-wet cycle. Buddhist statues at Yungang Grottoes. Beginning around the year 471 AD, in a second construction phase that lasted until 494 AD, the twin caves 5/6, 7/8, and 9/10 as well as the caves 11, 12, and probably 13 were constructed under the supervision and support of the imperial court. When the clay minerals experienced water swelling, a large number of secondary cracks were produced. The construction history of the Yungang Grottoes is generally divided into three phases: The first period (460 - 470AD) saw the . Since the 1950s, cracks in the sandstone have been sealed by grouting, and forestation has been implemented in an effort to reduce the weathering due to sandstorms. To avoid the error of the experimental results due to the difference between the individual feldspar sandstone samples, the change rate of the longitudinal wave velocity was used as an evaluation indicator. The saturated water absorption of the feldspar sandstone could be used to characterize the amount of internal pores or fissures. The Grottoes have been a UNESCO World Heritage site since 2001. Until the 20th century no attempt had been made . Since the 1950s, cracks in the sandstone have been sealed by grouting, and forestation has been implemented in an effort to reduce the weathering due to sandstorms. Yungang Grottoes - Wikipedia Relative content of the minerals in the feldspar sandstones of Groups A and B after the dry-wet cycles. At the same time, the load continued to be carried by the internal undamaged structure, causing the internal stress to increase rapidly due to the reduction of the load-carrying area. The Yungang Grottoes are considered by UNESCO to be a "masterpiece of early Chinese Buddhist cave art. It can be seen that apparent deterioration of the Group A feldspar sandstone was not notable in appearance from the outside, while the apparent deterioration of the Group B feldspar sandstone was very pronounced. After the processes of core drilling, cutting, polishing, grinding, cleaning, and drying, a standard sample of feldspar sandstone with a size of 50mm 100mm was finally obtained, as shown in Figure 2. The surface roughness of the feldspar sandstone was determined by laser confocal scanning microscopy (LCSM). The Yungang Grottoes. The grottoes are divided into east, middle, and west parts. Compared with the attributes of the Group A feldspar sandstone, the diffraction intensity and relative content of the feldspar in the Group B feldspar sandstone decreased and those of the kaolinite in the Group B increased. In addition, the variation rate of Group B was higher than that of Group A. "Yungang Grottoes Academy was launched on the basis of the former Datong Institution for the Preservation of Yungang Grottoes," said Zhang Zhuo, head of the academy. From the changes in the apparent properties of the feldspar sandstones in Groups A and B in Section 3.1, it can be seen that the water and salt solution could cause a certain degree of damage to feldspar sandstone. After 6h, the sample was completely immersed in the erosion solution until the end of the immersion duration. Architectural Pillars of the Wuhua Cave, Photo from Official Site. A Visual Tour (Video), Behind the Scenes of Ancient Greece: Exploring the Daily Life of its People (Video), Trove of Ancient Artifacts Discovered in Paestum Include Dolphin Statuette of Eros, TheiaGreek Goddess of Light, the Sun, the Moon, and Wisdom, Greeces East Attica In Antiquity: Playground Of Gods, Heroes And Heroines, Genghis Khan: The Man Who Forged the Most Feared Empire in History (Video), Mighty Queens: 8 Royal Powerhouses Who Shaped History (Video), Ashurbanipal: The Most Powerful Man on Earth (Video), How Leonardo da Vinci Made a "Satellite" Map in 1502 (Video), The Enigma of Sweden's Great Lake Beast (Video), Smallpox Vaccine Sheds New Light on Mysterious Kaspar Hauser Legend, Mystery of the Latin Inscribed Artifacts Found in Arizona (Video), Haunting Tales: Exploring 4 of the Most Famous Ancient Ghost Stories. A stress readjustment could be used to characterize the nonuniform load-carrying capacity of materials. 37043714, 2010, in Chinese. Therefore, to avoid unnecessary repetitive efforts, the stress-strain curves of the Group A samples numbered 0-1, 5-1, 10-1, 15-3, 20-1, and 25-2 and of the Group B samples numbered 0-1, 5-1, 10-2, 15-3, 20-1, and 25-1 were selected for analysis. Today, 45 main caves remain intact, which house more than 59,000 statues, ranging from a few centimeters to 17 meters in height. The Yungang Grottoes were dug over a span of forty years (CE 453-493), during the Northern Wei Dynasty. Average relative content of the minerals of the feldspar sandstones. This is an open access article distributed under the, Since the sandstone samples in this study were made of feldspar sandstone, the K-Na feldspar in the unit chemically reacted with water to form kaolinite (formula (. 40, pp. The colossal Buddhist statues that sit within the Cliffside caves have survived the rise and fall of dynasties, wars, and revolutions, but it is the harmful effects of modern-day living, including industrial pollution, which is the greatest threat to these ancient wonders, according to a report in the NY Times . Norimitsu Odachi: Who Could Have Possibly Wielded This Enormous 15th Century Japanese Sword? Yungang Grottoes - A UNESCO Heritage Site in Datong | Trip Ways 33, no. The Yungang Grottoes Research Academy has been exploring diverse applications of digital technologies for the conservation, research, management, and exhibition of cultural heritage. Many of the Buddhas now appear in the golden glory envisioned by their creators. This was because of the hydrolysis of feldspar to form kaolinite. The relative content of the minerals in the feldspar sandstone was analyzed by the semiquantitative analysis software Xpert Highscore Plus, as shown in Table 2. 6571, 1997. The Yungang Grottoes represent the excellent Buddhist grotto art . To protect these stone cultural relics from weathering, the Yungang Grottoes Research Institute, among other organizations, has also implemented a large scale of protection work, including protection measures such as seepage prevention, dehumidification in the Grottoes, and drainage. The ancient civilization of Greece is a historical period that has long been a subject of fascination and intrigue. Past researchers [20, 21] used micro/mesoscopic observation equipment to study the destruction mechanism of modified materials such as cement mortar and mudstone, and the relationship between their research results and the macroscopic destruction mechanism was widely recognized. Currently 45 . In 2001, the Yungang Grottoes were made a UNESCO World Heritage Site. After the dry-wet cycles, the surface layer of the feldspar sandstone under loading was the first to be damaged, as manifested by the spalling of many rock pieces from the surface, which was more pronounced with the increase in the number of dry-wet cycles. X-ray diffraction of the feldspar sandstones before and after the dry-wet cycles. In recent years, the observation of the microscopic properties of rock materials has gradually become an important and universal means of research. In this section, the deterioration processes of feldspar sandstone after dry-wet cycles were comparatively analyzed from the micro/mesoscopic perspective using the means such as XRD, SEM, and laser scanning confocal microscope (LSCM). The weathering mechanism of the water-rock interaction consisted of three effects, namely, the hydrolysis of K-Na feldspar, the water swelling of the clay minerals such as kaolinite and the dissolution of soluble minerals. Advances in Materials Science and Engineering. Due to its promotion, Pingcheng saw an increase in construction work. 99, pp. As a UNESCO World Cultural Heritage, statues, reliefs, murals, buildings, and other artistic elements of the Yungang Grottoes hold great religious, aesthetic, historical, and cultural values. Viking Ships: More than Fearsome Weapons of the Open Seas, Archaeologists in Britain Shocked to Find 25 Mesolithic Period Pits, The Most Complex Border in Europe (Video), How the US Stole Thousands of Native American Children (Video), What Did Ancient Greece Really Look Like? Yungang Grottoes: Cave 6 - Dome The massive Yungang Buddhist grottoes were cut from the mid-5 th Century to early-6 th Century AD. Then all of the samples were taken out and cooled to room temperature, thus completing a dry-wet cycle of feldspar sandstone. All rights reserved. The area was excavated along the mountain, extending 1 km (0.62 miles) from east to west, revealing 53 caves and over 51,000 stone statues. Wikipedia:Yungang Grottoes Belem et al. Additionally, the variation rate of Group B was higher than that of Group A. Y. Chen, C. J. Wang, X. F. Sun et al., Progress on mineral solubility and mechanism of dissolution secondary porosity forming in clastic reservoir, Bulletin of Mineralogy, Petrology and Geochemistry, vol. In addition, the variation rate of Group B was higher than that of Group A. He added that the cave-wall-strengthening project, which has been implemented for more than six decades, will be completed in one or two years. At the macroscopic level, the Group A and B feldspar sandstones had increased saturated water absorption and decreased longitudinal wave velocities, peak strengths, and elastic moduli, as well as remarkable deformation characteristics. Yungang Grottoes, enjoying a long history of over 1,500 years, is one of the three leading grottoes in China together with Mogao Grottoes in Dunhuang and Longmen Grottoes in Luoyang. The light source was X-ray Cu target radiation (=0.154056nm).