Conservation and Research Institute, Dunhuang Academy, Dunhuang, 736200, Gansu, China.
Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University, Lanzhou, 730000, Gansu, China.
Environ Monit Assess. 2019 Nov 17;191(12):755. doi: 10.1007/s10661-019-7961-7.
The Dunhuang Mogao Grotto is a famous Buddhist monument and was inscribed in the list of world cultural heritage sites by UNESCO in 1987. Water poses a major threat to the preservation of this heritage even though it is located in an arid region. This study was conducted to investigate the effect of rainfall on rock erosion. Specifically, the formation mechanism of slope runoff and the erosion threshold of rainfall were analyzed, and erosion-prone areas of the site were identified. This was carried out using field artificial rainfall simulation testing, and the results inform methods of preventing rainfall-induced cliff erosion. In addition, the rainfall threshold and erosion-prone areas obtained from the experiment were further validated and optimized using monitoring data for natural rainfall and historic documentation. The threshold value of erosive rainfall obtained by empirical statistical analysis method was found to be similar to that obtained by the runoff generation mechanism. The areas identified as prone to erosion using field tests coincided with areas of historic erosion as recorded in site documentation. Furthermore, the forecast grade of cliff slope erosion and its erosion-prone areas are determined after comprehensive analysis of the results obtained by these two methods. The research results are critical for the monitoring, early warning, and prevention of cliff slope erosion. The research methods can also be used as reference in areas for which rainfall data are missing.
敦煌莫高窟是著名的佛教古迹，于 1987 年被联合国教科文组织列入世界文化遗产名录。尽管地处干旱地区，但水仍然对其保护构成了重大威胁。本研究旨在调查降雨对岩石侵蚀的影响。具体而言，分析了坡面径流的形成机制和降雨侵蚀阈值，并确定了遗址易受侵蚀的区域。这是通过野外人工降雨模拟试验进行的，试验结果为防止降雨诱发的悬崖侵蚀提供了方法。此外，还利用自然降雨和历史文献的监测数据对实验中获得的降雨阈值和易侵蚀区域进行了验证和优化。通过经验统计分析方法获得的侵蚀性降雨阈值与产流机制得出的结果相似。野外试验确定的易侵蚀区域与现场记录的历史侵蚀区域相吻合。此外，综合分析这两种方法的结果后，确定了悬崖边坡侵蚀的预测等级及其易侵蚀区域。研究结果对监测、预警和预防悬崖边坡侵蚀具有重要意义。该研究方法也可作为缺少降雨数据地区的参考。
