降雨过程中敦煌石窟围岩水汽运移机制研究

治理因水分运移而产生的病害，是石窟寺保护领域长期面临的难题和挑战。国内外针对石窟水害防治已经开展了大量研究和实践，但地处干旱环境的敦煌石窟，在有效阻隔了窟顶渗水、无凝结水和无地下水补给的背景下，部分洞窟在阴雨天气条件下仍存在明显返潮现象，使窟内文物面临威胁。鉴于此，本课题针对低含水砂砾岩围岩在降雨、日照、温度、气压等环境变量作用下的水分迁移效应问题，从敦煌石窟部分洞窟渗水的实际情况出发，通过敦煌石窟降雨过程中气象因子对崖体含水率影响的权重分析，借助室内试验确定各因子对砂砾岩样品含水率的影响速率，确定降雨过程中环境变量的边界条件及加载方式，基于典型洞窟的简易地质模型构建大尺寸砂砾岩物理模型，利用多场耦合实验室开展大尺寸模拟试验，并通过天然降雨过程的现场试验对模型试验结果验证，揭示降雨过程中敦煌石窟围岩的水汽运移机制，以期为西北干旱环境下大量类似石窟水害的防治提供理论依据和科学支撑。

Controlling the diseases caused by moisture transfer is long-term problem and challenge for the field of grottoes' protection. A large number of researches and practices have been carried out on the prevention and control of grottoes' water hazards at home and abroad. However, under the background of effectively blocking the roof seepage, no condensate water and no groundwater recharge in the Dunhuang Grottoes which is in the arid environment, some grottoes still have obvious damp reciprocating phenomenon under cloudy and rainy weather conditions, which poses a threat to cultural relics in the grottoes. .This project in view of the moisture transfer effect of low water content sandy conglomerate rock under the action of environment variables such as rainfall, sunshine, temperature, pressure, the influence rate of each factor on the water content of sandy conglomerate samples and the boundary conditions and loading modes of the environment variables during the rainfall process will be determined by laboratory experiments. In order to achieve the goal, the research will start from the actual water seepage situation of some caves in Dunhuang grottoes, and through the weighted analysis of influence of meteorological factors on water content of cliff body in the process of rainfall in Dunhuang grottoes. Based on the simple geological model, a large-scale sandy conglomerate physical model can be built, and the large-scale simulation tests can be carried out in the multi-field coupling laboratory. And the model test results will be verified through field tests of natural rainfall processes. Finally, the mechanism of water vapor migration in the surrounding rock of low water content sandy conglomerate grottoes of Dunhuang Grottoes will be explained. The research results will provide a theoretical basis and scientific support for the prevention and control of a large number of similar grottoes in the northwest.