Master of Science (MS)
Geology and Geophysics
Geotechnical sediment type of levee foundation soils may be estimated by using cross-plots of shear-wave velocity and electrical resistivity for Louisiana levees. Best-fit polynomial models for estimating soil type in Japanese levees have been created using cross-plots of shear-wave velocity and electrical resistivity. A similar study or model for flood protection structures in the Mississippi River delta plain or other major river delta does not exist. We make the soil-type estimation model more relevant to the foundation soils in the Louisiana Coastal Zone by identifying silt in addition to sand and clay, and eliminating gravel as a dominant soil type. We analyzed seismic data, electrical resistivity data, and the soil type descriptions of 2 boring logs from the London Avenue Canal (LAC) levee in New Orleans, LA. Additional geophysical and Cone Penetration Test data from the “V-line” levee in Marrero is collected and analyzed. We combine the LAC and Marrero data to construct a cross-plot of shear-wave velocity, resistivity, and the dominant soil type with a total of 41 samples. In order to estimate soil types from different depths, we correct shear-wave velocity for overburden pressure. We find that larger grain sizes correlate to larger shear wave velocities and smaller resistivity values. Whereas clay can statistically be distinguished from soils dominated by either sand or silt sediment, sand and silt dominated soils plot with similar shear-wave velocity and electrical resistivity values. A correction for the effects of saturation on resistivity may improve our estimations to distinguish sand and silt dominated soils.
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Goff, Derek Stephen, "Study of Resistivity and Shear Wave Velocity as a Predictive Tool of Sediment Type in Levee Foundation Soils, Louisiana Gulf Coast Levee System" (2016). LSU Master's Theses. 903.
Lorenzo, Juan M