Chengde Mountain Resort Lesions Mechanism Of The Open-air Stone Relics

The Chengde summer mountain resort and the surrounding temples, are the world's largest existing imperial garden and the temple group. As a Qing Dynasty's politics activity center, the summer mountain resort and the surrounding temples complex fused the artistic feature of Chinese North and South gardens. Its construction form inherited ancient Chinese gardens, garden pond and the tradition of excellence Villa and became a classic example of landscape architecture. As an important component of Chinese classic gardens, various stone carvings in the summer mountain resort and the surrounding temples existed in large quantities. These exquisitely beautiful lithoglyph which had been called the stone of our treasures, demonstrated the high level of carving, fully embodied the political, economic, and cultural levels of the prosperous time of Qing Dynasty, and had an important historical, artistic, religious and scientific value.After the founding of the nation all levels of cultural relics preservation departments had carried on the massive protections, restoration and rebuilding to the summer mountain resort and the surrounding temples, but these protective measures were mostly to protect the ancient construction and the garden primarily, the protection and repair of lithoglyph had not been given sufficient attention. These exquisite works of art are in outdoor, under the destruction of natural factors and human factors in the role, many stone appeared flaky powder, crack, weathering partial deletion, with a serious impact on the integrity of the appearance of lithoglyph. Moreover, many diseases are still in developmental stages, with the deterioration of the environment in recent years (acid rain, air corrosive gas increase) stone corrosion rate greatly sped up.Aiming at the summer mountain resort and the surrounding temples lithoglyph disease situation, we made systematic investigation and mastered the basic types of diseases. On this basis, we firstly used polarized light microscopy and X-ray diffraction and other modern scientific instruments, and carried XRD and physical image, the water absorption and porosity analysis on the stone surface of the matrix material and the corrosion products and materials. We obtained the basic material of lithoglyph of the Chengde summer mountain resort was neutral acid tuff with high porosity and water absorption, wass easy to have hydrolysis reaction. This reflected this batch of carved stone had relatively poor stone material, higher porosity and water absorption, was not conducive to the long-term preservation. Meanwhile test results showed stone surface layer and surface weathering product contained the high soluble salt, mainly for sulfate, nitrate and carbonate.Through above analysis result, we simulated lithoglyph corrosion environment in laboratory, and carried on artificial accelerated aging experiment to the lithical sample, obtained the alteration of temperature, the soluble salt dissolution and the heavy crystallization were the key factor which the pathological change occurred. The soluble salt caused damage to the overall intensity of rock, and freeze-thaw aggravated erosion on the foundation which the soluble salt corroded, continued stripping, thus intensified the erosion of soluble salt to the rock. Under the water function, this accelerated volcanic tuff lithoglyph decency corrosion process, and finally caused the lithoglyph cultural relic the serious decency corrosion.