Study On Geophysical Prospecting New Techniques And Applications Of Large Ancient Mausoleums

Large ancient tombs(and mausoleums)are an extremely important part of archaeological research with its diverse external architecture and internal structures and rich funerary objects.The simple use of high-cost and low-efficiency trenches and the "Luoyang Spade" drilling have become increasingly ineffective in today's increasingly complex cultural relics protection work,and combining it with many mature scientific and technological means can be more conducive to the practice of field archaeology in the future.Geophysical methods play an increasingly important role in ancient tombs investigations by virtue of their non-destructive and efficient advantages.Combined with the characteristics of ancient tombs and the needs of investigations,the current geophysical methods are mainly faced with three categories of problems:environmental adaptability,detection resolution and non-uniqueness of geophysical inversion itself Most of the field environment is complex and changeable,and the existence of large graves,the effective detection of ancient tombs should be carried out under the premise of ensuring accuracy.As a result,the environmental adaptability of various recording geometries is greatly challenged,and subsequent data processing and mitigation of non-uniqueness in inversion have many difficultiesIn this paper,the pseudo-three-dimensional observing system has been popularized and applied in view of the environmental adaptation limitations of the orthogonal(or parallel)and spoke-like pseudo-three-dimensional observing systems in the existing electrical resistivity tomography.Taking the pseudo-three-dimensional observation study of the Shaoxing Yueguo aristocratic large tomb as an example,the conventional two-dimensional survey line is arranged in multiple azimuths,which improves the collection efficiency and ensures the coverage of the survey line to the grave.The results show that the multi-azimuth line layout can cope with the complex field environment and the undulating terrain.The two-dimensional observation gives a certain but not comprehensive and detailed information.The pseudo-three-dimensional observation can not only supplement the information of the two-dimensional interpretation of the missing,but also correct the result of the two-dimensional characterization and the results are basically consistent with the results of the drilling data.For the terrain adaptation problem of the electrical resistivity tomography full three-dimensional rectangular grid observation system and the contradiction between the collection efficiency and the detection depth derived from this problem,this paper evaluates the feasibility of an annular observing system based on a rectangular grid full three-dimensional observing system to cope with the above problems.Using the rectangular observations that can be realized by the existing instrument and the acquisition characteristics of the instrument itself,the electrode moving sequence and voltage and current data under the rectangular observation system are extracted and matched with the coordinates under the annular observing system,then calculate the apparent resistivity collected by the annular observing system for inversion.The feasibility study included model comparison tests and actual investigations of Shaoxing Yueguo aristocratic large tomb.The model test initially examined the feasibility of the annular observing system.The practical application obtained the burial depth and internal structure similar to the above-mentioned pseudo-three-dimensional analysis and drilling data,which further verified the rationality and feasibility of the annular observing system.The existing problems and the space for improvement are also discussed.There are many research and application examples of geophysical techniques for investigating tomb chambers,but the application of the shape and layout of large mausoleums including the main tomb and ancillary construction facilities is still rare.In combination with the archaeological literatures,this paper attempts to use integrated geophysical techniques to investigate a large mausoleum in the Xiaoshan county of Hangzhou,Zhejiang province.The synergistic detection and interpretation of the magnetic gradient method,electrical resistivity tomography and ground penetrating radar,inferred the depth and scale of the main tomb of the mausoleum and the orientation and depth of the auxiliary facilities such as mausoleum path,and gave the plane and profile layout.In addition,according to archaeological literatures and detection results,the age of the mausoleum has also been validated.The results of the experimental excavation partially confirmed the results of geophysical investigation,indicating that integrated geophysical techniques are effective for detecting large mausoleums.