Investigating the Effect of Pore Fluids on the Stability of Unsaturated Geomaterials

该项目的主要目标是研究多相岩土材料的应力-应变响应，并阐明孔隙流体状态的自然和/或人工改变的力学含义。岩土材料的多相内涵使其孔隙网络成为组分之间物理相互作用的便利环境，并对这些材料在应力作用下的变形和破坏起着至关重要的作用。降雨入渗、地下水位波动和流体的注入/提取只是地质材料与间隙流体之间显著相互作用的一些例子。因此，迫切需要预测性理论来解释体积分数和孔压的变化如何产生意想不到的故障。这项研究将基于多相岩土材料的先进本构模型和分叉的数学理论相结合。为此，将从理论的角度讨论现代建模方法的预测能力，目的是确定导致岩土材料破坏的流体力学机制。这项研究将有助于更好地理解岩土材料的破坏机理，并有可能弥合多相介质力学理论和材料稳定性基本概念之间的差距。这些进展对于将目前仅适用于完全饱和的岩土材料的一系列工具推广到一般饱和条件很重要，并为预测不稳定机制的启动设计了新的战略。这项研究对社会的好处将是更好地理解控制地质灾害发生的机制，为岩土基础设施设计提供新的建模工具，并改进对跨越地质构造的多相流后果的预测。

The key objective of this project is to investigate the stress-strain response of multiphase geomaterials and elucidate the mechanical implications of natural and/or artificial alterations in the state of the pore fluids. The multiphasic connotation of geomaterials makes their pore network a convenient setting for the physical interaction among constituents and plays a crucial role on how these materials deform and fail under stress. Rain infiltration, water table fluctuations and injection/extraction of fluids are only some examples of the remarkable interaction between geological materials and the interstitial fluids. There is therefore a pressing need for predictive theories explaining how changes in volume fractions and pore pressures can generate unexpected failures. The study will be based on the combination of advanced constitutive models for multiphase geomaterials and the mathematical theory of bifurcation. For this purpose, the predictive capabilities of modern modeling approaches will be discussed from a theoretical standpoint, with the goal of identifying the hydro-mechanical mechanisms that can originate failure in geotechnical materials.This research will contribute to an improved understanding of the mechanics of failure in geomaterials and has the potential to bridge the gap between the mechanical theories for multiphase media and the fundamental concept of material stability. These advances are important to extend to general saturation conditions a series of tools currently available only for fully saturated geomaterials and devise novel strategies for predicting the initiation of unstable mechanisms. The benefits of the research to society will be a better understanding of the mechanisms that govern the occurrence of geo-hazards, novel modeling tools for the design of geotechnical infrastructures and improved predictions of the consequences of multiphase flow across geological formations.