Soil-structure interaction affected by artificial water recharge: A data-driven scheme

This work is an attempt at understanding soil-structure interaction mediated by ground-water flow, from data which have been collected for the past 9 years. The case study was motivated by two phenomena observed late in 2015: a) onset of sub-millimetre fissures in the walls of a corner room on the 1st floor of a building; b) injection of water (“artificial recharge”) under the building foundations through a well intended solely for the seepage of rain-water, excavated a few metres away from the corner pile. Artificial recharge was suspected to alter “soil- structure interaction” and cause fissures. Investigation had to rely solely on observation i.e., on collection of data, hence the “data-driven” feature of the research Programme. The Site where the building is located is characterised by its physical properties (SECT. II). Two hydraulic plants at the Site are described (SECT. III). Programme Management (ISO 21503:2022) provides the main methodological framework (SECT. IV); PÉSTEL analysis is summarised. The account continues with SECTNS. V to VII: they describe the chain of Projects (ISO 21502:2020) belonging to the Programme, where a Deliverable or an Output (≡ Result) by a Project becomes a Resource (≡ Method, Material) for the next one. SECT. VIII is devoted to the main Outcome by the whole Programme: the hydro-geological and structure- mechanical interpretation of a runaway accident occurred to a hydraulic plant; the accident caused upconing at a well ≃ 35m away from the injection well and fissure response. SECT. IX discusses the accident by relating fissure dynamics to recharge-drainage cyclic uplift. SECT. X provides recently acquired evidence of structure evolution. SECT. XI concludes by emphasising the need to understand process interaction and by summarising Lessons learned.