In order to utilize the land on natural soft clay deposits or artificial reclamation fills as urban development purposes, prediction of long-term subsidence is important. Purpose of this study is to find out quantitative consolidation behavior by the analysis based upon natural analogue point of view. Taking inner and central parts of Tokyo Bay area on Alluvial soft muddy formation as the sample sites, the authors made thorough review and compilation of the historical results of borehole measurements and laboratory tests. At four representative model sites, the consolidation behavior was examined in detail by plotting the relationship between void ratio and effective overburden pressure, normalized by constant liquid limit or clay content. The results showed us that time-dependent change of field scale compression index values could be obtained from the existing data.