Thoughts on a Simple Means of Estimating Settlement in Thick Soil Layers in Accordance with Hypothesis B Casey J. Shepheard 1(&) and Michael G. Williamson 2 1 EPSRC FIBE CDT, University of Cambridge, Cambridge, UK cjs225@cam.ac.uk 2 Mott MacDonald, Cambridge, UK Abstract. Settlement of structures founded on soft soil is a primary concern for geotechnical engineers. Buildings will frequently fail due to reaching the ser- viceability state due to cracking and or tilting from uneven settlement well before reaching the ultimate limit state. There is ongoing discussion in the geotechnical engineering community on the mechanics of settlement, specifically the point at which secondary consolidation (creep) begins: ought Hypothesis A or Hypoth- esis B be adopted? This paper addresses the challenges in estimating Hypothe- sis B, where the strain values in both thick and thin soil samples at the end of primary consolidation are believed to be a function of both the change in void ratio, which is understood well, and creep, which is not. A new empirical-based model, the EOP-Anchor model, is proposed to estimate Hypothesis B strain as a function of settlement time and soil thickness in conjunction with standard lab- oratory oedometer test data on thin samples. 1 Introduction The settlement of soft soils is a subject of significant interest to geotechnical engineers, due to the effects ground movements can have on structures (e.g., McMahon and Bolton 2014). Changes in the ground profile may have large effects on a structure founded upon it. These ground movements frequently cause structures to reach their serviceability limit state (e.g., due to cracking, uneven floors etc.) well before the ultimate limit state is thought to have been reached by the soil (Craig 2004, p. 185). Therefore, engineers should have a clear picture of settlement magnitude and rate. The aim of this study is to review the process for estimation of settlements and investigate whether this can be simplified for early analysis of ground movements. Forces from loading a soil are carried by the soil grains and fluid in the pores (usually assumed to be water). A load to a soil is carried immediately by the water in the pores creating an increase in pore water pressure and thus a state that is not in equilibrium (Terzaghi 1943, article 99), before transferring to the soil grains gradually. the time taken for this excess pore fluid pressure is a function of a number of different variables including the soil permeability and composition. Settlement is frequently divided into three distinct phases: immediate settlement, primary consolidation settlement and secondary consolidation settlement (Almeida and © Springer Nature Switzerland AG 2019 H. Shehata and B. Das (Eds.): GeoMEast 2018, SUCI, pp. 54–63, 2019. https://doi.org/10.1007/978-3-030-01923-5_5