Comprehensive detection technologies for the complex goaf in highway tunnel

Because of the disorderly exploitation in the mountainous region,the formed goaf often brings hidden danger to tunnel construction and long operation.In order to determine the status of goaf,the engineering geological conditions was analyzed at first,and then proposed 'deep-shallow’ combination detection method by EH4 and AGI,'long-short’ combination detection method by TGP and GPR.By giving an example of Comity Tunnel,we detected the complex coal mine goaf according the topography and obtained the distribution profiles of the goaf by analyzing the detection data and the results.The results were compared with the actual conditions,it shows that the program can circumvent multiple results and limitations of single method,delimit the section and scope of goaf,which could provide the basis for the route design,risk assessment and treatment.