Research and Application of the Detection Technology for the Grouting Quality of the Shield Tunnel by the Ground Penetrating Radar
Due to the dense distribution of steel bars inside the prefabricated segments of the shield tunnel,the effectiveness of the ground penetrating radar method for detecting the den-sity of grouting behind the segments has always been controversial.To eliminate dispute,through analysing the principle of the ground penetrating radar technology and numerical simulation of the impact of different steel bar spacing on radar wave propagation,the theo-retical basis for detecting defect bodies behind the segment of the shield tunnel is explained;based on the physical condition of the shield tunnel,the numerical model containing the cavi-ty filled by water,the cavity filled by air,and the sand containing water and the mud contai-ning water,as well as the numerical model with different sizes of cavities filled by water,are constructed to simulate the waveform characteristics of different defect bodies;based on the 1∶1 physical model with defect bodies of the shield tunnel,the detection effect of the ground penetrating radar on the defect bodies is tested;finally,three drilling and coring ex-amples of a shield tunnel under construction are illustrated.The results indicate that the ground penetrating radar method has a good detection effect on the defect bodies behind the segment of the shield tunnel,as demonstrated by the theoretical principle,numerical simula-tions,physical model and engineering examples.The overall conclusion is that the ground penetrating radar method is currently the best method for detecting the quality of grouting in shield tunnels.
ground penetrating radarshield tunnelnumerical simulationphysical modeldrilling and coring
万方数据
维普
