Was bedeutet statisches Enthalpiegleichgewicht für das Bauwesen? Beitrag, Leistungsfähigkeit und Grenzen einer zustands- und energiebasierten Herangehensweise

This document is a discussion paper addressing the question of what Static Enthalpy Equilibrium (SEE) means for civil engineering, with a particular focus on geotechnical stability problems. The paper does not propose a new design method, calculation procedure, or safety concept. Instead, it introduces SEE as a state- and energy-based interpretive framework intended to clarify the physical meaning of established geotechnical concepts. Classical approaches to problems such as hydraulic heave, piping, and soil liquefaction are widely accepted and have proven reliable in engineering practice. However, their underlying physical mechanisms are often expressed implicitly, especially when instability develops locally, progressively, or in a strongly geometry-dependent manner. The SEE framework interprets such phenomena as energy-driven state transitions of saturated soil–water systems, where stability is associated with the existence of a statically admissible system state and instability with the loss of such a state. Within this perspective, established concepts such as effective stress, critical hydraulic gradients, the Terzaghi block, and safety factors are reinterpreted without being replaced or challenged. Safety factors are explicitly retained and understood as experience-based measures accounting for uncertainties in parameters, models, and boundary conditions. No recalibration of safety levels is proposed. The paper deliberately adopts a cautious and non-normative stance. SEE is presented as an interpretive tool to support understanding, comparison, and communication of geotechnical stability problems, not as a substitute for established engineering practice. The discussion also includes a carefully framed reflection on soil liquefaction, applying the same safety-related restraint as for hydraulic heave and piping. The document is intended for civil and geotechnical engineers from practice, planning, and research and aims to contribute to an open technical discussion on the role of state- and energy-based thinking in geotechnical engineering.