Constitutive and numerical modelling of wet granular flow and deformation

拟议的研究侧重于发展计算机模拟能力，以分析土壤的移动性和移动性。地面移动和土体移动是岩土工程中的重要课题。对于许多工程项目来说，大大小小的运动都很重要，有时甚至是至关重要的。滑坡、泥石流等土体的大运移和快速流动威胁着人类的安全，造成财产损失。因此，已采用定量风险分析(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分析土壤运动和土壤移动性。 分析土壤运动和移动性有两种方法：连续体方法和不连续(离散)方法。连续体方法已被广泛应用于分析小到中等运动。当土壤运动时，有相当多的物质混合，这不能用连续介质方法有效地模拟。当材料经历剪切破坏时，会出现分离和分离。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。 水对颗粒表面施加压力，因此对粒间力有影响。在高固体浓度下，水的运动对单个颗粒施加阻力，从而导致颗粒运动。另一方面，土壤颗粒的存在改变了流型。这被称为双向固液耦合。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，水的流动会导致孔压的变化，进而导致变形。这是一个固体变形-流体耦合问题。在离散建模中，孔压和粒间力变化的计算不是微不足道的，因为离散建模只对单个颗粒建模，而不是对孔隙空间进行建模。 这项研究的重点是改进数值技术，以便在不连续介质模拟中加入水。该模型基于连续和间断相结合的方法来模拟流体和固体。此外，能够确定用于离散建模的微观力学参数也很重要。这项研究将考察微观和宏观材料参数之间的关系，以便为不连续谱建模提供真实的模型参数。 这项研究在许多工程和科学领域具有重要意义和应用价值，这些领域涉及流体和颗粒物质之间的相互作用，如河流中的沉积物分析、水文运输、泥石流和地质灾害管理、土壤中的过滤、油井出砂等。

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.