四川广元千佛崖石窟造像表面风化的环境地质问题分析  

Study on Environmental Geology Problem of Surface Weathering of Grotto Statues in Guangyuan Qianfoya,Sichuan

作　　者：宗静婷[1,2] 王淑丽[3] 张忠永 

机构地区：[1]西安文理学院旅游与环境系,陕西西安710065 [2]西北大学地质学系,陕西西安710069 [3]西北有色地质研究院,陕西西安710065 [4]西北有色地质勘查局,陕西西安710061

出　　处：《地球科学与环境学报》2011年第2期185-190,共6页Journal of Earth Sciences and Environment

基　　金：陕西省科技厅软科学项目(2008RK61)

摘　　要：采用温湿度测试、石窟造像渗水实验、石窟造像吸水的红外成像、岩石特征分析等手段,对四川广元千佛崖石窟造像表面及其周围环境进行监测,以及对石窟造像岩石特征进行分析。结果表明：进深较大的窟室内外存在2℃~4℃的温差,岩石0~40 mm深度范围内温度与外界气温存在显著相关性;石窟造像岩石主要成分为长石、石英、黑云母及黏土矿物,岩石渗水率和吸水率高,表层风化程度高。环境和岩石特征揭示广元千佛崖石窟造像的风化机理为：石质文物棱角部位和小型石窟造像对温度的变化敏感,当气温出现变化时,其温度变化剧烈,而其他部位相对滞后,从而导致石窟造像表层岩石在热胀冷缩的应力下出现微裂隙,并随着微裂隙逐渐增大,石质文物表面出现疏松、起壳、鳞片剥落等病害。同时微裂隙的出现增加水入渗的途径并扩大水-岩相互作用的面积,含水矿物的水合压力和结晶压力使岩石内部结构疏松逐渐破坏;水化学作用导致可溶盐离子形成,并随水毛细迁移在石窟造像表面聚集,导致石窟造像表面酥碱、锈染、彩绘层空鼓等失去原真而破坏。最后提出在窟龛上面加盖窟檐和在崖顶及立面坡面刻槽疏排水流等石窟造像治理措施来减缓其表面风化。Based on the temperature,humidity,seepage,infrared imaging and rock character tests,the surface of grotto statues and the surrounding environment were monitored,and the rock characters of grotto statues were analyzed in Guangyuan Qianfoya,Sichuan.The results showed that the difference in temperature was 2 ℃-4 ℃ for the deep grotto inside and outside;there was significant relationship between the temperature outside and that within the grotto with 0-40 mm depth;rocks of grotto statues were mainly composed of feldspar,quartz,biotite and clay mineral;water permeability and absorption were high,and the degree of surface weathering was serious.The characteristics of environment and rock revealed the weathering mechanism of grotto statues in Guangyuan Qianfoya.The mechanism was that the angles of stone heritage and small grotto statues were sensitive to temperature,and other parts were insensitive,so that there were microfissuring in the surface rocks of grotto statues under the stress of expansion and contraction;the loose,shell and scales falling in the surface of stone heritage occurred with microfissuring expansion.At the same time,the ways of water infiltration increased and the areas of the water-rock interaction were expanded by microfissuring;the internal structures of rock were damaged by water and crystallization pressures of enhydrite;water chemistry resulted in the formation of soluble salt ions,and the ions gathered on the surface of grotto statues with the water capillary migration,so that the grotto statues were damaged by salting the surface,dying rust and painting layer hollow.Finally,some measurements,which included building eave above the grotto and draining water along the groove in the elevation slope and the top of cliff,were put forward to improving the surface weathering of grotto statues.

关 键 词：广元千佛崖 石窟造像 温度 湿度 岩石特征 风化机理 环境地质 

分 类 号：K879.29[历史地理—考古学及博物馆学] X144[历史地理—历史学]