From Liquefaction to Structural Reconstruction in Saturated Granular Materials: Coupled Grain Settlement Upward Water Flow and the Formation of a Densified Structure

This working paper examines how a saturated granular material reconstructs a load-bearing structure after liquefaction. It addresses the coupled motion of grains and pore water, the development of supported material from the base upwards, and the conditions under which further rearrangement becomes arrested. A four-zone column model distinguishes reconstructed material, a finite reconstruction layer, a mobile grain–water mixture and an upper water layer. Separate phase conservation differentiates water flux through a fixed vessel section from Darcy flux relative to moving grains. A joint gravitational energy balance accounts for both grain descent and water rise without double counting hydraulic expenditure. Solid-volume conservation provides an exact relation between terminal settlement and final mean porosity. Determining that settlement requires additional information about contact geometry, collective motions and dynamically accessible rearrangements. Repeated excitation is interpreted as a sequence starting from the structure attained in the preceding event. The measured initial porosity, individual arrest states, the limit of further permanent densification under a specified excitation protocol and the material minimum-void-ratio reference are distinguished. The manuscript includes a comparison with Zander’s column experiment, a numerical reference calculation and a four-sphere illustration of local support and collective descent. The proposed Static Enthalpy Equilibrium (SEE) density boundary remains a separate opening question and is not derived or validated by this reconstruction model. This is a working paper for scientific discussion and has not undergone journal peer review. Derived conservation relations are distinguished from conditional model solutions and unresolved structural closure requirements.