Determination of lame’s parameters (λ and μ) from compressional and shear wave velocity for Uyo and environ, southeastern Nigeria

Abstract

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 4^o45' and 5^o15' N and between longitudes 7^o45' and 8^o30' 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.