Development of micromechanically-based models for geomaterials with coupled multiphysics

开发基于微机械的多物理场耦合岩土材料模型

• 批准号: 155220-2011
• 负责人: Wan, Richard
• 金额: $ 2.48万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569433
• 关键词: Development; micromechanically; based; models; geomaterials

Geomaterials are a class of random heterogeneous materials that are endowed with a rich and complex microstructure involving various phases. As such, coupled transport and mechanical processes of great importance in many contemporary engineering problems can only be effectively analyzed using a micromechanical approach with multiscale modelling. Most current methods of analysis are largely phenomenological, requiring a large number of parameters that lack physical significance. In this proposal, we investigate the instability of an unsaturated soil at low water content where the solid grains interact through a network of water menisci. As the degree of saturation is increased such as in a wetting scenario, the menisci coalesce and develop into a continuous liquid phase. The loss of liquid bridges between grains triggers a microstructural change that leads to a diffuse instability failure characterized by an outburst in kinetic energy. A micromechanical formulation of the above processes is worked out to describe the relative balance between the various forces involved leading to various regimes of material behaviour in a multiphysics setting. Clay-like materials are also studied with proper focus given to short range forces arising from particle electrical charges, given the particle size and ionic solution in the pores. Within this new paradigm of analysis where the physics of small scale phenomena is highlighted and upscaled via mathematical tools such as homogenization, generally accepted concepts relevant to geotechnical practice can be either clarified or amended. The proposed work involves physical, analytical and computational modelling. The gain in resolution in such modelling approach will permit the analysis of many difficult problems such as the swelling behaviour of a protective shale cap layer above a shallow oil sand reservoir under steam and solvent injection for stimulating oil production. Such an analysis will provide crucial information regarding the potential for a blowout and oil leakage to the surface. Another example is the catastrophic collapse failure of unsaturated soil slopes at constant external (gravity driven) loads.

岩土材料是一类具有丰富而复杂的微观结构的随机非均质材料。因此，在许多当代工程问题中非常重要的耦合运输和机械过程只能有效地使用多尺度建模的微观力学方法进行分析。大多数当前的分析方法主要是唯象的，需要大量缺乏物理意义的参数。 在这个提议中，我们研究了在低含水量的非饱和土的不稳定性，其中固体颗粒通过水凝胶网络相互作用。随着饱和度的增加，例如在润湿情况下，水聚结并发展成连续的液相。颗粒之间的液体桥的损失触发微观结构的变化，导致扩散不稳定故障的特征在于在动能的爆发。上述过程的微机械配方制定出来，以描述所涉及的各种力量之间的相对平衡，导致各种制度的材料行为在一个multiphysics设置。粘土类材料也进行了研究，适当的重点给予短期的力量所产生的颗粒电荷，给定的颗粒尺寸和离子溶液中的孔隙。在这种新的分析范式中，小尺度现象的物理学通过数学工具（如均质化）得到强调和升级，与岩土工程实践相关的普遍接受的概念可以得到澄清或修正。拟议的工作涉及物理、分析和计算建模。 这种建模方法的分辨率提高，将允许分析许多困难的问题，如在蒸汽和溶剂注入下，浅层油砂储层上方的保护性页岩盖层的膨胀行为，以刺激石油生产。这种分析将提供有关井喷和石油泄漏到地面的可能性的关键信息。另一个例子是非饱和土边坡在恒定外部（重力驱动）载荷下的灾难性坍塌破坏。