Abstract:
In the construction of a high-speed railway tunnel in Hubei Province, two kinds of advanced prediction techniques, geological radar technique and elastic wave reflection method, are comprehensively used. Combined with the excavation of the tunnel, the results are as follows: Ground penetrating radar(GPR)is greatly affected by the conductor and electromagnetic interference in the tunnel. The radar reflection profile presents hyperbolic shape. The area with the same phase axis is generally the karst development area, and the strong amplitude is generally the interface between the abnormal body and the normal surrounding rock. Elastic wave reflection technology has certain limitations in the detection of irregular geological defects, water content and unfavorable geological bodies parallel to the tunnel axis, and has good detection effect in the broken rock area. Through the analysis of reflected wave velocity, the spatial position and scale of the interface corresponding to the reflecting layer are determined by the intersection angle of tunnel axis and the distance between tunnel surfaces. Combined with the dynamic characteristics of seismic wave, the abnormal characteristics are the change of P-S wave velocity ratio and wave velocity. In this paper, the advantages and disadvantages of GPR and electromagnetic interference prediction methods are analyzed based on the prediction cases, which can provide reference for the optimization of tunnel advanced prediction scheme.