Maximum shear modulus of calcareous sand in Dejebel Dahar, Tunisia and its dependency on applied stress

¹ Kyung Hee University, Department of Civil Engineering, 17104 Yongin, South Korea
² University of Gabès, Civil Engineering Laboratory, 6029 Tunis, Tunisia

^* Corresponding author: choohw@khu.ac.kr

Abstract

The present experimental investigation aims at investigating the small strain stiffness of calcareous sand as a function of applied stress. The calcareous sand was sampled at Tunisia's Dejebel Dahar region, and the shear wave velocity (V_s) of calcareous sand was measured using modified oedometer cell equipped with bender elements. The results of this study demonstrate that the V_s of the tested calcareous sand is smaller than that of silica sand with minimal crushable particles at relatively low applied stress (σ); however, V_s of calcareous sand is greater than that of silica sand at high σ, reflecting strong dependency of calcareous sand on σ. The applied stress dependency of soils can be expressed as a power function of applied stress (V_s = α (σ / 1 kPa)β, where α = V_s at σ = 1 kPa and β = stress exponent). Generally, the single α-β can capture the dependency of V_s on σ, and the typical β value for sand is around 0.25. The measured β of tested silica sand was around 0.20; while, Tunisia calcareous sand shows β of greater than 0.32, and the dependency of V_s on σ cannot be captured by single α-β. This can be attributed to the fact that the variation of V_s of tested calcareous sand with increasing σ reflects not only fabric change but also particle crushing.