Abstract:The detection and forecasting for geological structure ahead of the tunnel and laneway are the one of the most difficult issues in the world. Much application work is performed with the seismic reflection wave method in China at present. But the study on detecting observation system in 3D space and data processing techniques is not performed considerably. The perfect exploration effect is not gained in the practical detecting projects,and this situation is not good for the extending application of the advanced forecasting techniques of tunnel and laneway. The different detecting conditions that will be met ahead of the tunnel and laneway through ultrasonic experiments in the flume are presented. The forecasting data using multi-shot-receiver system of the reflection wave are collected,and the refraction scanning migration for the collecting data is realized. The simulation results show that the multi-shot-receiver system has obvious reaction on the wave impedance of the interfaces in different geological conditions. The migration results are in accordance with those of practical interfaces,but the distinguishing ability for the back interfaces will be unsatisfactory when multi-layer media are detected. So the 3D multi-component and stereoscopic data collecting methods are proposed,and wave equation migration techniques are developed to improve exploration ability for complex geological structures ahead of the tunnel and laneway.