Research On Non-contact Scanning System For Quality Defect Of Highway Tunnel

In recent years,China’s tunnel engineering has made unprecedented development.The number and mileage of tunnel engineering are still increasing.In order to ensure the smooth passage of traffic,the durability problem of tunnel engineering is particularly important.Structural detection is an important part of finding tunnel structure problems and ensuring tunnel engineering safety in time.The quality of the tunnel concrete lining has a great influence on the long-term stability of the tunnel,the normal use of the use function and the beauty of the appearance.Therefore,lining and surrounding rock quality detection is not only the main way to control the quality of lining concrete construction,but also the first step to evaluate the safety of the operation tunnel.Using g Ground Penetrating Radar(GPR)to detect tunnel lining structure is an advanced detection method widely used in recent years.But the current GPR detection is mostly manual handheld radar antenna,which has many problems,such as slow detection speed and high safety risk of detection personnel.The development of non-contact radar detection system can effectively solve the above problems.The contents of the study are as follows:(1)The application of non-contact radar detection in the field of tunnel engineering detection is a frontier research in this field.Firstly,the theory of tunnel quality defect detection based on non contact ground penetrating radar(GPR)is studied.(2)A non-contact radar detection model of tunnel quality defect is established,and the response characteristics and laws of the target under different air distances and the response characteristics and laws of the target in the medium with different conductivity are obtained.(3)Through the establishment of a forward model,the typical lining model radar profile of highway tunnel and the quality defect radar profile of the typical lining of highway tunnel are obtained,and some shortcomings of the Gpr Max forward software for this model are analyzed.(4)Relative algorithm is compiled for radar data post-processing.(5)A test platform has been set up for highway tunnel detection.In this paper,the response curve and fitting formula between radar reflection signal strength and different air distance based on forward modeling are obtained.The response curve and fitting formula of radar reflection signal intensity and dielectric conductivity combined with forward modeling are fitted.The non contact radar profile of the typical lining model of highway tunnel under different radar antenna frequency and the quality defect radar profile of the typical lining of highway tunnel under different radar antenna frequencies are obtained.The measured data of different radar antennas are obtained.