游客呼吸对敦煌壁画白粉层的损害机理研究

壁画的美学价值主要在表面,壁画的表面主要由白粉层和颜料层组成。游客进入洞窟会使洞窟内的微环境(即温度、湿度、CO2)在短时间发生变化,这会产生一个连续的应力而使壁画疲劳老化,颜料层和最外层产生剥离、微裂隙等损害。为了研究游客呼吸对敦煌壁画的损害机理,采用澳大利亚TPG-1260-5×400-TH植物生长箱模拟游客呼吸作用导致的莫高窟窟内微环境的干湿变化;从宏观与微观的角度分析了在温度、湿度、CO2循环变化条件下,壁画白粉层的劣化情况。并得到了以下结论:宏观方面,随着干湿循环次数增多,白粉层逐渐出现起甲、龟裂等损害,损害的总面积随着循环次数增加而逐渐增大,单个剥离块的面积随着循环次数增加逐渐变小;白粉层的开裂有从中间向两边扩展的趋势。微观方面,通过循环前后的电镜照片分析,可知循环后与循环前相比,小孔隙数量减少,大孔隙与中孔隙的数量增加。

The Study on the Damage Mechanism ofthe powder layer at Dunhuang murals

,The aesthetic value of wall paintings mainly on its surface. The microclimate change by the turbulence generated by the motion of visitors at a moment which result is a continuous stress and fatigue thus,leads to weakening, microfessuring and flaking the outermost layer or the colour coating. In order to study the damage mechanism of wall paintings at Mogao Grottoes influenced by tourists breathing , this paper use TPG-1260-5×400-TH Humiture console cabinet simulate microclimate change by tourists breathing. Under conditions of the change in temperature and humidity and CO₂ , the damage mechanism of wall painting was analyzed from macroscopic and microscopic.In the aspect of macroscopic , the result showed that the plaster layer gradually emerged damage like crack and shell etc .With the increase in cycles, the area of the damage gradually increase and the area of a single crack blank decrease. The cracking tend is from the middle to the sides. In the aspect of microscopic, By analyzing the pictuctures of electom microscopy which taked before and after cycles, we known the number of microscopy decreased and the number of mesopores and macropores increased .