Guangyuan Qianfoya The Cliff Stone Conservation, Environmental Geology Problems

The disease of stone artifacts can be divided into two types:instability problem and weathering problem. The instability problem is the unstable of rock structure and stone local crisis of relying on the rock (hill) body of stone artifacts. The weathering problem is destruction of cultural appearance in millimeter and centimeter range of artifacts surface-Rock material is the product of geological rock that deformation and failure of rock is the closely related of not only the complex nature of the causes and structure, but also temperature,onfining pressure, pore water and other environmental factors. Therefore, the mechanism of disease should first survey the geological environment, and understand relationship between diseases of stone artifacts in dependencies of the geological environment and local climate conditions.The cave area of The thousand buddha cliff belonged to the subtropical humid monsoon climate zon, located in the tectonic western margin of the northern section of the yangze, the longmenshan orogenic belt and foreland basin area. adjacent the daba mountains orogenic belt and foreland basin in the east.The Single rock type expose in cave area of Qianfo Ya what is the thick layer and laminar shale argillaceous sandstone of The thousand buddha cliff system of Jurassic,t is J2-Q3. The major minerals are the feldspar, the quartz, and anhydrite and clay minerals, such as chlorite, montmorillonite. The stratigraphic occurrence is 210-240°<23-29°. The grains of argillaceous quartz sandstone of The thousand buddha cliff cliff are loose, the dry compressive strength range of values is in the 29.9-4.763 MPa, the wet compressive strength range is between 10.467-11.079MPa, the compressive strength value is low, softening coefficient is only 0.33.The deep structural is integrity in cave area of The thousand buddha cliff rock, however,the rock slope crisscross distribute regional structural joints with the formation of several tectonic movement. There are three groups of joints of more development, their occurrence are:26-76°<62-82°,100-122°<63-77°,315-336°<65-78°. The features of regional structural joints has wide range of occurrence, stability, the larger, extended farther, wider spacing, joint surface smooth, more feather-like and the conjugate "x"-type section of the faculty. The rock was cut into multiple cracking by large number of joints that not only provides the interface conditions to speed up the deep weathering and further weathering,but also easy to produce crack- sliding and falling damage collapse owing to diamond or wedge block in The thousand buddha cliff, the most serious along the slope direction of the joint.The mechanism of weathering of rocks was reveal by the temperature test in different parts of the surface of different cultural by using infrared temperature dt8380, and seepage of rock by situ experiments, and moisture detection by infrared imaging system in japan nec th7700sp.the mechanism of surface weathering of grotto express in two ways:temperature and frost weathering, water-rock interaction.The temperature and frost weathering shows in what way:rhythmic layer spallation of cave rock; mineral grains connected damaged by the different of mineral expansion coefficient; the expanding role by heavy rain poured over; crystal structure of the damaged by absorbent mineral crystallization pressure and splitting by the role of ice.The water-rock interaction is chemical reaction between solution and mineral in statue. The chemical reaction results not only redistribution between rocks and water re-allocation of chemical elements, but also diversification of rock microstructure.The mechanism of its role in four way:the first, its reduces the internal cohesive force, increases rock porosity, promotes feldspar, gypsum and rock salt dissolved, so that orosity increased in rock; the second, water swelling properties of clay minerals would increase pressure and damage the internal structure, such as montmorillonite, etc. The third, fissure water quickly evaporates, the expansion of salt crystals from water volume will generate strong pressure to the rock, causing stone fragmentation, etc. The chemical dissolution would expand the crack rock from feldspar and other minerals into kaolinite, montmorillonite, etc. At the same time, the soluble salts composition is gradually migrated to the surface from the joints,lead to disaster, such as powder of surface, painted crust, painted hollowing, and painting shed.There grow a large number of microorganisms surface of caves of Qian foya, including bacteria, fungi, algae, lichen, moss and so on. The metabolism of plants and bacteria often precipitates solution that have organic acid, nitric acid, nitrous acid, arbonic acid and ammonium hydroxide will corrode and deposit on surface of carves. The mechanism of microbial destruction is solution of silicate minerals (feldspar, clay minerals, etc.) by proton swap, ligand complexation, oxidation-reduction biofilm in supergene weathering environment.The vibration level of passing vehicles was field tested by one-third of the short period seismometer of speed-type cmg-40t-1. the results show that single vehicle through the caves in the vicinity not effect to integrity grotto, but may induce instability and destruction of artifacts or rock of the critical steady-state. While the single vehicle vibration is not a devastating effect on the integrity of caves, long-running vibration would cause fatigue damage on The thousand buddha cliff cave.The steady-state level of geological of rock caves of the The thousand buddha cliff was judged by the structure surface, weathering and other geological characteristics of rock slope, and marked form of the zoning map. Strengthening governance systems and comprehensive should be implemented in Guangyuan The thousand buddha cliff cave area, especially in dangerous areas as soon as possible. The degree of weathering was comprehensive evaluated by the diseases characterized of the size of different types, through surveys, surveying, photographic, sampling, etc. And a disease map of focus cave was drawn. The precaution measures of weathering disease should be developed wind of the biofilm of the surface, reduce and slow down the speed of weathering on stone artifacts, because inorganic and organic surface treatment agents are varying degrees of change of original cultural. The influence of human factors should be reduce through the governance environment.