This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/sed.12537 This article is protected by copyright. All rights reserved. DR. PASCAL BERTRAN (Orcid ID : 0000-0003-3334-9869) Article type : Original Manuscript Experimental soft-sediment deformation caused by fluidization and intrusive ice melt in sand PASCAL BERTRAN 1,2* , MARIANNE FONT 3 , ARNAUD GIRET 3 , KEVIN MANCHUEL 4 , DEBORAH SICILIA 4 1 Inrap, 33130 Bègles, France (E-mail: pascal.bertran@inrap.fr) 2 PACEA, Université de Bordeaux, CNRS, 33415 Pessac, France 3 Normandie Université, UNICAEN, CNRS, M2C, 14000 Caen, France 4 EDF, TEGG/Service Géologique Géotechnique, 13097 Aix-en-Provence, France Associate Editor – Nick Eyles Short Title – Experimental fluidization and intrusive ice growth ABSTRACT Identifying the driving mechanisms of soft-sediment deformation in the geological record is the subject of debate. Thawing of ice-rich clayey silt above permafrost was proved experimentally to be among the processes capable of triggering deformation. However, previous work failed so far to reproduce similar structures in sand. This study investigates fluidization and intrusive ice formation from soil models in the laboratory. Experimental conditions reproduce the growth of ice-cored mounds caused by pore water pressure increase during freeze-back of sand in permafrost context. Excess pore water pressure causes hydraulic fracturing and the development of water lenses beneath the freezing front. Later freezing of the water lenses generates intrusive ice. The main