The Applied Research Of GPR Detection In Geological Flaws Of High Arch Dam Foundation Rock

In the process of construction of high arch dam hydropower station,the quality and stability of the foundation rock is the core problem whether the whole project can go smoothly,and the kinds of geological flaws of foundation rock will affect the excavation,the project processing measure,even the stability of the whole dam foundation.In order to ascertain the specific information of geological flaws in foundation rock,the GPR can be used as an effective tool and means of detection and research.The paper takes the high arch dam foundation rock as the research object.On the basis of the combination of predecessors' research results,a large number of field data and statistical analysis of results,firstly,establish GPR interpretation standards of geological flaws based on the basic principle of GPR;secondly,make the specific analysis of all kinds of geological flaws through the GPR detection results;finally,combine all kinds of field data,validate the results of the interpretation and make the forecast.The specific research results as follows:(1)Compare the influence of all kinds of field media to radar waveform,provide a basis for possible interferential waveform in the process of geological flaws' feature extraction,and analyse and sum up the extraction method of reflecting layer.(2)Extract the relaxation depth of foundation rock through the GPR detection profile,and extract the radar wave velocity between the relaxation area and complete rock mass,and relaxation area in different lithology to make a contrastive analysis,as well as analyse the frequency spectrum of relaxation zone,providing a basis for analysis of relaxation area.(3)Make a GPR forward modeling as the method of FDTD on fault and disturbed belt,according to the modeling results,ascertain the information of fault and disturbed belt's position and depth in GPR profile,finally analyse the frequency spectrum of fault and disturbed belt,providing a basis for analysis of fault and disturbed belt.(4)According to all kinds of field survey data and calculation analysis results,make a validation analysis and comprehensive ascertain of the detection results of all kinds of geological flaws through the GPR.Finally,make a study on related applications of interpretation results,includeing time dependent analysis of relaxation area,impact analysis of footrill and geological structure to relaxation area,and forecast analysis of all kinds of geological flaws.The results have a wide application,and the effect is pretty good.