Empirical Strength Equations for SUT Silty Clay

Abstract

K₀-compression test results on undisturbed and remolded SUT (Suranaree University of Technology) silty clay samples show that the virgin compression line of both samples is identical and the effective overburden pressure is much lower than the maximum past pressure. This reveals that SUT silty clay is overconsolidated destructured clay. From the back analysis of pile load test result, the S_u and N relationship, where S_u is undrained shear strength and N is standard penetration number, is proposed:  where 29 < N < 68. It is also found that the Stress History and Normalized Soil Engineering Property (SHANSEP) technique is valid for SUT silty clay. The empirical equation between undrained shear strength and stress history is presented in the form: , where s¢_vc is vertical consolidation pressure and OCR is overconsolidation ratio. These two empirical equations are incorporated with static formula to predict ultimate load of four micro-piles. The predicted and measured values are in good agreement, reinforcing the application of these two equations.