Surrounding rock loose circle support theory has been widely recognized and accepted by engineers

how accurate and fast detection loose circle depth better for engineering services become all issues of concern

the new Lan-xin railway girder tunnel based on field test

the test section of surrounding rock loose circle depth by single-hole sonic test method

the ground penetration radar(GPR) for detection and combining with the ground stress and physical and mechanical parameters of rock mass according to the result of the benchmark for the numerical simulation analysis shows that with single span acoustic test results for reference

GPR test results and acoustic method test results are basically the same

in the surrounding rock water area test results in some deviation

geological radar emit electromagnetic fields to water area is relatively sensitive

transmit and receive interference is bigger

but the geological radar as a rapid and nondestructive detection method should be strongly applied: Due to the numerical calculation of surrounding rock loose blasting without considering the influence of the circle

the calculation results are slightly smaller that ones obtained by the acoustic detection

but the trend is basically consistent. Numerical calculation should be based on the physico-mechanical parameters of rock mass stress and according to the test results

so as to make the results of calculation more real and better for the decision of project service.