Influence diagram for DS #1. Optimisation of the initial surcharge. The square node ΔH₀ indicates that first a value of ΔH₀ is chosen, at a cost C_sur,0(ΔH₀). The now fixed ΔH₀ influences the evolution of the settlement S_t and the overconsolidation ratio at unloading OCR_fin as well as the time t_target when the target settlement is reached, defined by S(t_target) = s_target. Monetary consequences due to project delay and residual settlement result from these quantities. The interaction between ΔH₀ and the geotechnical model is represented in a simplified manner