Determination of lame’s parameters (λ and μ) from compressional and shear wave velocity for Uyo and environ, southeastern Nigeria
In this work, compressional and shear wave velocity values were determined for the estimation of Lame’s first and second constants (λ, μ) for Uyo and environ, which helped in the determination of elastic parameters of top soil as well as the degree of stability of engineering foundations. The study area lies between latitudes 4o45' and 5o15' N and between longitudes 7o45' and 8o30' E in the Niger Delta region of Southern Nigeria. A 24-channel signal enhancement seismograph was used in generating seismic waves. The mechanically generated seismic disturbances sensed by the geophones were received and recorded by a seismograph cascaded with the geophones. Shear modulus (μ) values ranged from 0.21 × 108 to 0.63 × 108 N/m2 with an average of 0.43 × 108 N/m2 for layer 1 and 0.78 × 108 to 2.55 × 108 N/m2 with an average of 1.40 × 108 N/m2 for layer 2. Also, λ values ranged from 0.20 × 108 to 0.58 × 108 N/m2 with an average of 0.40 × 108 N/m2 for layer 1 and 0.73 × 108 to 2.36 × 108 N/m2 with an average of 1.30 × 108 N/m2 for layer 2. The results indicate that the topsoil under study can support load that is being subjected to shear stress, provided the materials within the layer are well compressed.
Faculty of Science, University of Uyo