Influence of Cement Type on Go of a Carbonate Sand

A new setup was developed to enable measurement of shear (V_s) and compression (V_p) wave velocities (and hence G_o and M_o) under K_o conditions for reconstituted geomaterials. Any of V_s or V_p may be measured from elastic waves propagating either horizontally or vertically. The system has two particular advantages for horizontally propagating waves. First, the shear wave transducers accessed the sample externally. Second, they can be rotated in the vertical plane, so that V_s can be measured in any skew plane. The setup was used to investigate the influence of cement type on the small-strain stiffness of a carbonate sand, treated with four different cementing agents, namely calcite, Portland cement, gypsum and epoxy. The aspects investigated due to the cementation were: (1) the overall evolution of G_o, (2) the shear stiffness anisotropy, and (3) the influence of vertical stress (σ'v) on G_o. The study shows that the type of cement can have a substantial effect on the stiffness anisotropy. For example while the calcite removed the initial stiffness anisotropy of the untreated soil, both Portland cement and epoxy reversed the stiffness anisotropy; and the gypsum cement increased the initial stress-induced anisotropy. These findings have important implications in modeling naturally or artificially cemented soils.

• Introduction

• Setup for measuring wave velocity under Ko conditions

• Soil and cementing agents

• Sample preparation

• Go of uncemented LP sand

• Go of cemented LP sand

• Conclusions

• Acknowledgements

• References