CO_2劣化龙门石窟碳酸盐岩的机理模拟试验研究  

Simulation experimental study on CO_2 corroding carbonate in Longmen Grottoes

作　　者：方云[1] 黄志义[1] 张新鹏[1] 喻媛[1] 王晓东[1] 范子龙 杨刚亮 

机构地区：[1]中国地质大学(武汉)工程学院,湖北武汉430074 [2]龙门石窟研究院,河南洛阳471023

出　　处：《中南大学学报（自然科学版）》2015年第7期2626-2634,共9页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金面上项目(40972183)~~

摘　　要：为探究CO2通过凝结水劣化碳酸盐岩体的机理,选取凝结水病害较典型的龙门石窟潜溪寺,监测游客数量、CO2质量分数变化、窟内凝结水生成规律和石窟岩体化学成分变化。在室内采用自主研制的模拟劣化试验装置进行CO2对石窟岩样的劣化作用试验,定量推算其宏观劣化速率。借助扫描电镜研究碳酸盐岩微观劣化机理。研究结果表明:碳酸盐岩质量损失在试验过程中呈指数增长,灰岩劣化速率约为白云岩劣化速率的2倍。当洞窟温度维持在25℃,湿度为85%,大气CO2质量分数为1×10-3时,潜溪寺1 a凝结水生成量高达227.87 kg,100 a后窟内岩体最高侵蚀深度约为4.35 cm,对石窟岩体造成严重破坏。劣化作用受晶体习性与解理面结构控制,由于晶格能和解理面结构的差异使得灰岩的侵蚀速率大于白云岩的侵蚀速率;矿物晶间空隙明显扩大,仅晶体边缘有明显磨圆、蚀边现象,说明劣化作用基本发生在岩体表层。In order to study the mechanism of CO2 corrosion through condensed water in Longmen Grottoes, experimental location was set in Qianxi Temple where there existed serious disease of condensed water. The number of visitors, variations of carbon dioxide concentration, the forming rules of condensed water and variations of grotto＇s chemical composition were monitored in Qianxi Temple. Self-developed simulation equipment for CO2 corrosion was designed, and the macro solution rate was calculated. With the aid of scanning electron microscopy（SEM）, carbonate＇s microscopic corrosion mechanism was studied. The results show that mass loss of carbonate rock grows exponentially, and limestone＇s solution rate is about 2 times of dolomite. When the temperature in cave is 25 ℃, humidity is 85% and CO2 concentration is 1 × 10-3, the condensate generation is up to 227.87 kg in QiarLxi Temple every year. One hundred years later, the highest erosion depths might reach 4.35 cm. Then defection is mainly controlled by crystallinity and cleavage structure, because these differences limestone＇s solution rate is greater than that of the dolomite. What＇s more, pores between crystal become clear, and only crystal edges have obvious rounding and corrosion, which means solution effect occurs in surface.

关 键 词：CO2 碳酸盐岩 龙门石窟 表面劣化 

分 类 号：P599[天文地球—地球化学]