Effect of Duxseal on Horizontal Stress and Soil Stiffness in Small-Amplitude Dynamic Centrifuge Models

Abstract

The constitutive behavior of soil is stress dependent. Therefore, geotechnical centrifuges are widely used to replicate full-scale stress fields, thereby ensuring the correct soil response within reduced-scale centrifuge models. A vibration absorbing material (such as Duxseal) is commonly employed to reduce the effect of reflected waves generated at the boundaries of rigid containers in dynamic centrifuge tests.However, such a material has the potential to deform laterally under the high horizontal stresses applied within centrifuge tests and consequently the initial at rest lateral earth pressure condition will not be maintained. A procedure to back-calculate the lateral earth pressure coefficient (𝐾) is presented in this paper.In addition, two experimental methods, which are implemented to evaluate 𝐾 by measuring the shear wave velocity from centrifuge-based air hammer testing and triaxial based bender element testing, are described.Results demonstrate that significant lateral earth pressure and soil stiffness reductions are observed within the upper soil region (top third of the model depth). In addition, the appropriate manipulation of the crosscorrelation method used to process shear wave signals is discussed and an empirical equation to predict the small strain shear modulus of the dry silica sand (HST95 Congleton sand) used in this study is provided.Outcomes of this study are directly applicable to small-amplitude dynamic centrifuge tests such as groundborne vibrations; some factors relating to large-amplitude seismic studies, such as soil inertial effects and