Application Of Geophysical Prospecting Methods In The Protection Of Stone Relics

There are many Stone cultural relics of different types, in China. They are widely distributed throughout the whole country. Some relics are located in extremely complex environment, which have geological problems. Take Grotto as an example, study geophysical methods applied in the conservation of stone relics. Grotto can be found in many places, from KunLun to the East China Sea, from WuYue to YouYan, so much so that Grottoes can be found everywhere in NanZhao of DianNan. Grotto is one of the very important stone relics, no matter from the value of cultural or from art. Because, Grotto is laden with history of ancient buddhism、carving、society affairs、 financial condition, and is unrenewable resources. To protect it is urgent, and the method of protection must be scientific and rational.Owing to the widespread of Grotto, protecting of the Grotto encounters environmental geological problems. So it is very important to find out the geological environment where grotto is located in and rock types of the grotto in the process of protection. In recent yeas,it is more and more widespread to use geophysical methods in the research of diseases of grottoes. Such as, taking advantage of the Ultrasonic Method for detecting rock weathering degree and the grouting effect and the localization of cracks; taking advantage of the micro-sounding method for detecting fracture extension and weathering depth; taking advantage of the direct current resistivity method for detecting the thickness of the bed rock that on the top of the grottoes and percolation passes; taking advantage of the ground penetrating radar for detecting the locate of the ancient tomb and buried grottoes; taking advantage of the Shallow Seismic Method for detecting the deep fracture development of grottoes and internal defects of stone carving. In addition, electromagnetic method can be used for detecting ancient tomb and buried block and fracture and karst.Here,taking Yungang Grotto and Northern Grotto as an example, the methods of seismic tomography and natural electric field and high density resistivity method are introduced into the Preservation of Cultural Relics of Caves.Through the method of field test, the result that seismic tomography have a high resolution ratio was got. After observing the same records, reading the time and spectrum, we can get the image of wave velocity and decayed wave velocity of the third Caves of Yungang Grotto and number165cave of Northern Grotto.The Yungang Grottoes and Northern Grotto is sensitive to electric differences, with the help of the method of high density resistivity, Located the ample flow and water seepage area.In addition, using the character that groundwater flow direction is the leaking positioning can find out the direction of water and the location of the leaking positioning of Northern Grotto.Combined with the geological radar method and multi-channel transient surface wave non-destructive geophysical methods common characteristics nondestructive testing,it Provides an adequate and effective basis for identify the grotto fissure water reservoir type and channel, reduces water-rock ration, protectes them from weathering.After the practical application of theory and field studies, compared with conventional means of exploration in Stone relics’s Conservation, geophysical methods has obvious advantages, comprehensive utilization of the different geophysical methods, mutual authentication, provide the basis for the grotto disease management, also provides a new idea for other grottoes conservation.