The Key Technology And Application Of Seismic Wave Method In Advance Geological Prediction Of Tunnel

In recent years,domestic investment in infrastructure construction has been increasing.The expressway and high-speed rail networks are expanding,and urban rail transit is growing rapidly,with more and more cities getting permission to build subways.With the implementation of a large number of transportation infrastructure construction projects,the number of tunnel construction up.As a concealed project,the excavation process of the tunnel is faced with vast strata,and various adverse geological conditions may be encountered in the construction,such as karst,fracture zone,water inrush and mud outburst.Especially in China's geological structure and hydrologic conditions of the complex southwest region,this situation is more frequent.In order to prevent all kinds of geological disasters and engineering accidents,it is necessary to carry out advanced tunnel geological prediction for the rock mass in the tunnel mileage,so as to obtain the geological conditions in the area of tunnel excavation direction in advance,so as to adjust the construction design scheme at any time and ensure the safety and economy of tunnel construction.This paper mainly studies the geological advance prediction of tunnel by seismic wave method.Based on the study of relevant theories and the engineering application of AGI-T3 during the internship of yunnan aerospace detection,this paper studies and applies several key technologies of signal acquisition and observation method,data interpretation method and signal analysis and processing in geological advance prediction.In this paper,based on the study of the existing advanced tunnel geological forecast observation system and the study of the microphone array sound source location method,a three-dimensional observation method based on the principle of "three-point location" is proposed to improve the location accuracy of abnormal bodies.In this paper,the high-sensitivity and wide-band three-component geophones are used to fully obtain the wave field information in front of the palm surface,and the conclusion that the signal prediction result of the interchangeover arrangement of the common receiving points is better than that of the ipside arrangement is obtained.Moreover,the empirical relationship between the velocity and density of longitudinal and shear waves can be used to calculate poisson's ratio,elastic modulus E,shear modulus G and other physical and mechanical parameters,providing a basis for lithology determination of geological advance prediction results.Usually collected seismic waves are full of clutter,n this paper,the difference of the main frequency range of effective wave and interference wave is used to carry out one-dimensional frequency band-pass filtering to eliminate the clutter signal and improve the signal-to-noise ratio of the whole seismic wave record.At the same time,the section equalization method is used to study the problem that the deep signal is weakened due to energy attenuation in seismic wave signal,and the deep amplitude of seismic wave signal is equalized,which can effectively realize the amplification of amplitude and improve the recognition degree of amplitude.