Propagation Characterics Of Rayleigh Wave In Rockfill Structure And Its Application In Density Testing

Rockfill structure is made of some natural materials by excavation,paving and compaction such as rock and crushed stones. For itsadvantageous properties, it is widely applied in civil engineering, such asrockfill dams, jetty, railway embankment and roadbed of expressway. Thedensity of rockfill is an important index expressed rockfill structure’sstrength, durability, quality characteristics. Therefore the detection andcontrol of its filling quality is directly relative to the use properties andservice life of the whole structure. As Rayleigh wave survey method hasbeen used widely in the field of engineering investigation and qualityexamination, based on the frequency dispersion characteristic of Rayleighwave the physics mechanical properties of rockfill are evaluated.Based on the basic principle of surface wave survey method, a seriesof models of rockfill structures under different density has been establishedto investigate the propagating history of surface wave by means of FEM.Shear wave velocity of rockfill layer could be obtained by analyzing thedispersive curves of rockfill structures under different density, withdifferent material properties of rockfill and fillers. Relation model betweendensity of rockfill structure and shear wave velocity of rockfill layer isfounded. Particularly analyzes the method applies in rockfill structure withhard roof and the influences of head roof on propagation of surface waves.The explanation and demonstration of higher mode of dispersion curvehave been included by the forward modeling method. we study the effectsof higher mode in inversion and the research result show that in the inversion of this class, especially the higher mode of dispersion curves areweak, the S-wave velocity structure of the rockfill structure inverted byfundamental mode of dispersion curves is reliable.With a view to application and frequency character, this paperintroduces the testing principle and analysis methods of high densitysurface wave method, while optimizing the course of data collection andmethod of data analysis, realizes the quantitative testing of density.Aim atSafety monitoring and evaluation problem in Wusong jetty, high densitysurface wave method is applied to test the density. Data acquisition system,the course of data collection and the analyzing results has been introducedin detail. According to the relation model between density and s-wavevelocity of rockfill layer, we quantitatively test the density of rockfill inWusong jetty.