为了研究凝结水对龙门石窟碳酸盐岩表面的风化作用机理,在现场进行凝结水观测、CO2浓度监测的基础上,利用自行研制、能模拟现场温湿度环境、能提供CO2外部来源,并能对反应过程进行监控的室内模拟试验装置系统对石窟碳酸盐岩风化作用进行模拟实验。实验结果表明,凝结水会造成碳酸盐岩表面的溶解,在CO2加入的条件下风化效果加剧,岩石的质量损失和孔隙率同时增大。经过78次的模拟试验后,灰岩岩样质量损失率为0.077%-0.088%,孔隙率由实验前的0.39%~0.40%增长到0.71%~0.74%;白云岩岩样的质量损失率为0.032%~0.038%,孔隙率由实验前的0.61%~0.68%增长为0.77%~0.85%;灰岩和白云岩的平均溶蚀深度分别为89.475μm和36.865μm,溶蚀速度分别为0.0956μm/h和0.0575μm/h,风化溶蚀作用对龙门石窟文物的影响破坏较大。
In order to research the weathering mechanism on the surface of carbonate rock by condensation water in Longmen grottoes, in light of monitoring for condensation water and CO2 concentration on the spot, the weathering process is stimulated with a self-made indoor experimental tester that enabling stimulating temperature and humidity conditions, providing external source of COz, and monitoring the reaction process. It shows that condensation water can dissolve the surface of carbonate rock, and that the mass loss and porosity of the rocks will increase when CO2 is added. Based on 78 tests, it proves that the mass loss of limestone sample is 0.077%-0.088% and the porosity increased from 0.39 %0.40 % to 0.71 %-0.74 % ; mass loss of dolomite sample is 0. 032 %-0.038 % and the porosity increased from 0.61%-0.68 % to 0. 77 %-0.85 %; the average corrosion depth and velocity of limestone is 89. 475 μm and 0. 0956 /1m/h, those of dolomite is 36. 865 μm and 0. 0575 μm/h. It is concluded that the corrosive weathering is of great damage to the culture relic in Longmen grottoes.