Numerical Modelling of Bender Element Test in Soils

A. Mandal, A. Patel, R. Ingale
bender element, Finite element method, Frequency, Time, Wave velocity

Shear wave velocities (Vs and Vp, respectively) are considered to be very useful for determining various dynamic properties of soils such as small strain shear modulus, Gmax, elastic modulus, Emax and the Poisson’s ratio, ν. Moreover, the index as well as engineering properties of the soil mass can be directly or indirectly correlated to Vs and Vp. However, the bender-extender element and soil interaction during wave propagation stage is difficult to monitor due to various sequential transformations as an electromechanical system. The experimental analysis is unable to reveal the hidden phenomena of wave propagation, boundary wall reflections etc. which otherwise facilitate to understand the complex and highly non-linear behavior at a certain level. The numerical analysis of bender element test simulation is less focused and very few researchers have studied the different aspects such as non-linear dynamics of element-soil system using different numerical approaches. In present study, a numerical code AbaqusTM based on finite element method (FEM) was used to simulate the bender element tests. Shear wave velocity was determined experimentally for six different types of soils and the results were compared with that obtained from numerical modeling. The objective of FE analysis in this research is to arrive at an accurate approximation of laboratory shear wave velocity in different soil materials modelled at varying input frequencies.

Keywords: Bender element, Wave velocity, Time, Frequency, Finite element method

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