Application of TETSP in advance prediction of water and mud inrush in karst tunnel

Water and mud inrush are easy to occur in the process of karst tunnel driving, in order to reduce the risk of tunnel construction, TETSP is used in the prediction of karst cave, water gushing and mud gushing in a karst area of Longxing tunnel. The characteristics of TETSP geophone, detection principle and arrangement of observation system are introduced. The signal-to-noise ratio of TETSP data under blasting and hammering is compared. The corresponding unfavorable geology abnormal law of TETSP is summarized. Several conclusions are drawn as follow. Firstly, the TETSP geophone with direct coupling method has high installation efficiency and can obtain the original waveform with high signal-to-noise ratio. Secondly, the seismic reflection data collected by blasting is higher quality than that by hammering excitation. Thirdly, the abnormal law of the corresponding TETSP of large-scale karst cave and dissolution fracture zone present as that the P-wave velocity and S-wave velocity are low but Poisson’s ratio is high. The prediction results of TETSP are consistent with the actual excavation of the tunnel which provide an important reference for the safe construction of the tunnel.