A Research On The Technology Of The Foundation Layer Of Murals In Tang Tombs In Shaanxi Province And Its Environmental Impact

Tomb mural is a special type of cultural relics in China for their fragile materials.It survives because it’s been underground so long.The production material and structure of the tomb mural itself determine that environmental changes have a great impact on it.As the direct carrier of mural art,the clay-based layer applied over the support is very important for the preservation of mural.The Tang Dynasty was the heyday of the development of China’s tomb murals.The preservation of murals in Tang tombs has always been the focus of academic research.In order to reduce the impact of environmental factors,the unearthed murals in Guanzhong area were removed to indoor protection.At present,there are few research achievements on it,the detailed study on the technological characteristics of the clay-based layer applied over the support of the murals in Tang tomb is rare,and there is no relevant research result on the influence of the preservation environment on the ground battle layer of the murals after excavation.Therefore,this article try to research the tang tomb murals production technology in Shaanxi Province,restores the production process of Tang tomb mural the clay-based layer applied over the support,and on this basis,explores the relationship between the production technology of Tang tomb mural the clay-based layer applied over the support and the temperature and humidity of the preservation environment,so as to accumulate scientific data for the research on the protection of Tang tomb murals,so as to provide reference for the future research on the protection of tomb murals.After this article research,exerting craft shows: the average thickness of the Ground is between 0.10～0.54 cm,the main component is calcite,and a certain amount of hemp fiber is added.The historical records.The thickness of the first clay-based layer mixed with straw applied over the support is uneven,and the composition is basically the same as that of the loess.It is mixed with wheat straw.The joint position of the white ash layer and the grass mud layer of the murals in different preservation conditions is observed.It is found that the two layers of materials are tightly combined.The condition is good,otherwise the condition is not good,further confirming that excellent production technology is one of the key factors for the long-term preservation of tomb murals.The results of the simulation experiment of the ground pole layer technology show that the effects of wheat straw fiber and hemp fiber as reinforcing materials were proved by experiments.Adding a certain amount of wheat straw fiber into the yellow mud can improve the internal bonding force of the mud texture bar,reduce the shrinkage cracking and deformation of the mud texture after drying,and increase the strength of the ground battle layer.It is easy to crack in the process of water loss and carbonization of lime paste.The reinforcement of hemp fiber can improve the water physical properties of gray matter and prevent the surface of lime layer from cracking due to too fast carbonization.The straw mixed mud layer is slightly dry and coated with lime layer,the combination between layers is better,and there will be no cracking and separation after drying.Through the simulation experiment of ground battle layer technology,the production process and technical requirements of ancient craftsmen to make mural floor battle layer are restored.The results show that: it is relatively stable for the murals of Tang Dynasty tombs which are removed and preserved indoors.the greater the humidity,the more significant the moisture absorption effect of the ground floor.The temperature is about 25 ℃ and the relative humidity is less than 70%.The clay-based layer applied over the support was little affected by the preservation environment temperature and humidity,and there was almost no change.Therefore,it was relatively stable for the fresco of the Tang Dynasty tomb that was removed to the indoor storage.When the relative humidity is higher than 70%,it is easy to cause damage by mold;if the relative humidity is not constant,it will lead to powdering and tortoise on the surface of grass mixed mud layer Cracks,Crazing,cracks between different layers of the ground battle layer and other diseases.For the murals of Tang tombs preserved indoors,The relative humidity should not be higher than 70% and the fluctuation of temperature and humidity should be reduced as much as possible.