Key Technique Research Of Geophysical Prospecting In Engineering Geology Of Qingdao Gulf Bridge

Qingdao gulf bridge is located in paralic zone of which geologic geophysics prospecting conditions are special and data processing also has the different characteristics of conventional marine seismic data and land seismic data. Through the investigation of geological data and combined with the actual survey to comprehensively analysis geophysical methods, this paper selects the effective marine geophysical exloration methods and appropriate processing mathods to get comprehensive results analysis ans explanation.Qingdao gulf bridge is in north of Jiaozhou Bay connecting Jiaozhou Bay on both sids. In view of statigraphy, the bridge belongs to Zhucheng-Jiaozhou formation, while from geostructure, it is located among north of Jiaonan block area. In this paper, the region types of strata and intrusive rock, structural features, fault blocks were summarized and analyzed. For the analysis of potential focal area, combined with the characteristics of regional gravity anomaly, magnetic signature and Moho-discontinuty, the regional geophysical field is studied.Because of the particularity of paralic zone surface condition, the construction work of different area, such as land, coastal mud flat, TZ zone and shallow water, has a big difference which will cause the larger seismice wave energy, frequence and pase difference. For the reason, we need study to obtain the wvaelet's statistical attributes. And then, we can make the compatibility processing for the shotpoints and the receiving-points for the purpose of removing the divergence between the shot-points and receiving-points to get the higher quality seismic data. The use of surface consistent TAR to eliminate seismic energy losses. To liminate the impact of seismic source to wavelet, using two-step statistical wavelet deconvolution to make wavelet phase to be corrected. Finally the use of matched filter to further eliminate the impact of wavelet difference and achieve an effective connection of seismic data and in-phase superimposes.For the suppression of multiple wave , optinal combination multi-suppressed method is applied. After analysis of multiple wave characteristics in the actual seismic data, the multiple wave is suppressed effectively by using the predictive deconvolution and f-k filtering and other mehtods.This paper focuses on the migration imaging of how to make zero-offset profile. In order to ensure high fidelity, high-resolution imaging used time migration before stack to eliminate the impact of the difference between the inclination and location.Combined with actual drilling data and magnetic curves to analyse and explain the processing results. The geologic position is divided and base rock depth is analysed.Comprehensively analysis of the results obtained, this paper give an effective processing and interpretation method of geological and geophysical prospecting results in Qingdao gulf bridge, the difficulties of key geophysical techniques is solved.