Study On Numerical Simulation Of Scattered Seismic Wave Field For Tunnel Geological Prediction Technology GPT

In twenty-first Century,the trend of Civil Engineering is to construct longer and deeper tunnel for which is more probably to meet complex geological conditions.In order to ensure the safety of construction,it is necessary to research and develop advanced geological prediction technology for tunnel.The technology of geological prediction for tunnel(GPT)by using Scattered seismic wave has long prediction distance and a strong compatibility for unfavorable geology.While the result of this technology is reliable.In this article,the author try to build a 2D-Tunnel-Stratum-Fault model based on plane stress to simulate the law of the spreading of artificial seismic wave in tunnel.Which to verify the technical reliability of GPT and to guide practical engineering.In this article,the research and results are following:(1)Considering the artificial earthquake centre and the distribution of detector,the author use Ricker wavelet to simulate the earthquake centre function.Using Finite Element Method to build 2D-Tunnel-Stratum-Fault model based on plane stress for Forward Numerical Simulation.(2)Forward Numerical Simulation about Scattered seismic wave of tunnel geological prediction is based on explicit dynamics analysis software named LS-DYNA.Analysing the snapshot and the displacement-time curve of the seismic wave field to provide an effective tool to verify the technical reliability of GPT.(3)The results show that the energy radiation of seismic wave spread in spherical form.In the same media,the speed of longititude wave is faster than the speed of transverse wave.In the course of time,it is obvious to observe the S-wave and P-wave separation.The seismic wave will reflection and transmission on the interface and the portal.The energy will attenuate during the reflection and transmission period.The amplitude of reflecting wave on portal is larger when the tunnel is short.It is possible that the reflecting wave of portal and fault will meet at the position of detectors and the waves will lap each other.(4)The research results of this study verify the validity and reliability of the geological prediction technology(GPT)for scattered seismic wave field.The Multi-sourse secimic exploration and the Multi-detector system can get more information which is important for geological prediction technology of scattered wave field.