Estimation of K ₀ in sand using DMT results

At-rest coefficient of earth pressure, K ₀, has been known to be an indirect property reflecting the stress history of sand. In this study, a series of CPTs and DMTs are performed in the calibration chamber to develop the method estimating K ₀ value. The method is based on the relation K _D/K ₀=χ(E _D/σ _m′) ^δ, which is developed by combining two relations such as E _D/σ _m′-ψ and K _D/K ₀-ψ. It is verified that the relation between K _D/K ₀ and E _D/σ _m′ works well for both Busan and Ticino sands. The suggested method is observed to provide more accurate K ₀ value than previous ones do, and it is applicable to OC sand as well as NC sand. Main advantage of the suggested method is to estimate the K ₀ value using only DMT results. As both K _D and E _D values are measured simultaneously in the same penetration, the spatial variation of sub-soil condition does not affect the accuracy of estimated K ₀ value.