四川广元千佛崖石窟造像表面风化的环境地质问题分析

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,...

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

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.