Determination of Lame’s Constants of Surface soils and Shallow Sediments from Seismic Wave Velocities [ READ ]
O. Akankpo and U. E. Essien
This paper presents the results of seismic compressional, P- and shear, S-wave measurements carried out on the unconsolidated top-soil at the different locations of the study area to determine Lame’s constants (µ and ?). The seismic refraction method employing P-wave and S-wave sources were used to generate seismic energies that propagated through the subsurface. A 12-channel seismograph with signal stacking ability was used together with high frequency (100 Hz) geophones on the top-soil. The geophone intervals were set to 5 m at all the locations. The results of the findings based on these parameters were Lame’s first constant, µ (1.3751 x 108 N/m2 – 2.8989 x 108 N/m2) for first layer and (2.9294 x 108 N/m2 – 7.0209 x 108 N/m2) for the second layer; Lame’s second constant (-2.023 x 108 N/m2 – 2.7290 x 108 N/m2) for first layer and (-3.9762 x 108 N/m2 - 3.000 x 108 N/m2 ) for second layer. The low values of these constants are symptomatic of occurrence of ripable anisotropic materials in the locations where they occur. The average depth of the top and weathered zone should be removed and refilled with geomaterials that may be resilient to carry engineering loads.
O. Akankpo and U. E. Essien
This paper presents the results of seismic compressional, P- and shear, S-wave measurements carried out on the unconsolidated top-soil at the different locations of the study area to determine Lame’s constants (µ and ?). The seismic refraction method employing P-wave and S-wave sources were used to generate seismic energies that propagated through the subsurface. A 12-channel seismograph with signal stacking ability was used together with high frequency (100 Hz) geophones on the top-soil. The geophone intervals were set to 5 m at all the locations. The results of the findings based on these parameters were Lame’s first constant, µ (1.3751 x 108 N/m2 – 2.8989 x 108 N/m2) for first layer and (2.9294 x 108 N/m2 – 7.0209 x 108 N/m2) for the second layer; Lame’s second constant (-2.023 x 108 N/m2 – 2.7290 x 108 N/m2) for first layer and (-3.9762 x 108 N/m2 - 3.000 x 108 N/m2 ) for second layer. The low values of these constants are symptomatic of occurrence of ripable anisotropic materials in the locations where they occur. The average depth of the top and weathered zone should be removed and refilled with geomaterials that may be resilient to carry engineering loads.
