A Non-contact Method For Evaluating The Quality Of Shallow Rock Layers Based On Infrared Detection Technology

Rock mass quality evaluation is an important foundation for engineering design and stability analysis.It is difficult to apply contact measurement for special types of rock masses such as high-risk,steep and cultural relics,and existing non-contact detection methods cannot meet the needs of comprehensive evaluation with multiple indicator,resulting in most rock mass quality evaluation methods being unable to be effectively applied.Therefore,it is necessary to further study the non-contact acquisition method of rock mass parameters and construct a new rock mass quality evaluation model.This paper utilizes infrared non-destructive detection technology to obtain rock mass quality parameters.Through theoretical analysis,indoor experiments,on-site experiments and other means,a non-contact shallow rock mass quality evaluation method is studied.The main content of the paper is as follows:(1)Construction of infrared non-destructive evaluation index system for rock mass quality.Based on the theory of infrared non-destructive detection,infrared non-destructive evaluation indicators for rock mass quality were determined,and fracture parameters and temperature parameters were used to characterize the integrity and deterioration state of rock mass.At the same time,the method of obtaining temperature parameters was discussed,the relationship between rock mass temperature and deterioration state was quantified,and the calculation formula for fracture parameters was derived.(2)Infrared non-destructive detection and parameter extraction of rock mass fractures.Indoor detection experiments on buried and exposed fractures were conducted,the effectiveness of infrared non-destructive detection technology in identifying fractures was analyzed under different working conditions,the heat transfer law of fractured rock masses was studied,the extraction error of fracture parameters was calculated and the feasibility of infrared nondestructive detection technology was verified in obtaining rock mass structure parameters.(3)Infrared response analysis of rock mass deterioration process.Deterioration tests on soluble salts were conducted,data information on sample temperature,mass,acoustic wave velocity,and thermal conductivity were obtained under different cycles,the evolution laws of various parameters were analyzed during the deterioration process,the correlation between temperature and various parameters was studied,the infrared response law was clarified during the rock mass deterioration process,and the reliability of temperature characterization of the degree of rock mass deterioration was verified.(4)Construction and application of a non-contact shallow surface quality evaluation method for rock masses.The weights of each indicator were determined using Analytic Hierarchy Process and Entropy Method,and a non-contact shallow surface quality evaluation method for rock mass was established combining Grey Relational Analysis.The non-contact shallow surface quality evaluation method was applied to the roof of Yuanjue Cave,and the evaluation results were verified through the number of volume joints.