Constitutive and numerical modelling of wet granular flow and deformation

拟议的研究重点是开发分析土壤流动性和运动的计算机建模能力。 地面运动和土壤流动性是岩土工程中的重要课题。对于许多工程项目来说，小型和大型运动具有重要意义，有时甚至至关重要。土壤运动量大、流动速度快，如滑坡、泥石流等，威胁人类安全并造成财产损失。因此，采用定量风险分析（QRA）来确定这些自然灾害造成的潜在威胁。在 QRA 中，有必要以合理的精度和可靠性来分析土壤运动和土壤流动性。 分析土壤运动和流动性有两种方法：连续体方法和不连续体（离散）方法。 连续统方法已广泛用于分析小到中等的运动。 当土壤运动时，材料会发生大量混合，无法使用连续介质方法对其进行有效建模。 当材料发生剪切破坏时，材料会发生分离和分离。 离散方法可以更有效地处理这些情况。 然而，在离散建模中很难将水考虑在内。 水对颗粒间力有影响，因为它对颗粒表面施加压力。在高固体浓度流动下，水的运动对单个颗粒施加拖曳力，从而导致颗粒运动。 另一方面，土壤颗粒的存在改变了流动模式。 这称为双向固液耦合。 由于固体变形和空隙空间的变化而产生的压力梯度可以引起水流。然而，水流会导致孔隙压力的变化，进而引起变形。 这是一个固体变形-流体耦合问题。 在离散建模中，孔隙压力和粒间力变化的计算并非微不足道，因为离散建模仅对单个颗粒而不是孔隙空间进行建模。 这项研究的重点是改进数值技术，将水纳入不连续介质建模中。该模型基于连续介质和不连续介质相结合的流体和固体建模方法。 此外，能够确定离散建模的微观力学参数也很重要。 这项研究将检查微观和宏观材料参数之间的关系，以便为不连续体建模提供真实的模型参数。 这项研究非常重要，适用于涉及流体和颗粒材料之间相互作用的许多工程和科学领域，例如河流沉积物分析、水力输送、泥石流和地质灾害管理、土壤过滤、油井出砂等。其中许多领域是加拿大与石油开采、河流沉积物和地质灾害管理相关的重要问题。

The proposed research focuses on the development of computer modeling capabilities in analyzing soil mobility and movement. Ground movement and soil mobility are important subjects in geotechnical engineering. Small and large movements are of important interest, and sometimes crucial, for many engineering projects. Large movement and fast mobility of soil, such as landslides and debris flow, threaten human safety and cause property damage. As a result, a quantitative risk analysis (QRA) has been adopted to determine potential threats due to these natural hazards. In QRA, it is necessary to analyze soil movement and soil mobility with reasonable accuracy and reliability. There are two approaches in analyzing soil movement and mobility: continuum and discontinuum (discrete) approaches. The continuum approach has been extensively used in analyzing small to moderate movement. When soil is in motion, there is considerable mixing of the material which cannot be modelled effectively by using the continuum approach. There are partings and separations of the material when it undergoes shear failure. The discrete approach can handle these situations more effectively. However, it is difficult to take water into consideration in discrete modelling. Water has an effect on the inter-granular forces since it exerts pressure on the surfaces of the grains. Under high solid concentration flow, movement of water imposes drag forces on individual grains which result in grain movements. On the other hand, the presence of soil particles changes the flow pattern. This is called two way solid-fluid coupling. Water flow can be induced by pressure gradients due to solid deformation and changes in the void space. However, water flow will result in changes in pore pressure which in turn causes deformation. This is a solid deformation-fluid coupling problem. The calculation of pore pressure and intergranular forces changes is not trivial in discrete modelling since discrete modelling only models individual grains and not the pore space. This research is focused on improving the numerical techniques to incorporate water in discontinuum modelling. The model is based on a combined continuum and discontinuum approach in modelling fluid and solid. Also, it is important to be able to determine the micromechanics parameters for discrete modelling. This research will examine the relationship between micro and macro material parameters in order to provide realistic model parameters for discontinuum modelling. This research is important and applicable to many fields in engineering and science that involve interaction between fluid and granular material such as sediments analysis in rivers, hydrotransport, debris flow and geohazard management, filtration in soils, sand production in oil wells etc. Many of these areas are important issues in Canada related to oil extraction, river sediments and geohazard managements.