Multiphysics modelling and photogrammetry applied to the study of Champlain clays and their geotechnical properties

尚普兰粘土位于加拿大东部人口稠密的圣劳伦斯河谷的大部分地区。这些粘土以其对重塑的高敏感性和高压缩性而闻名。这些特性常常导致代价高昂的土流和建筑物的大沉降。***新的实验方法和数值模拟工具为尚普兰粘土及其岩土力学特性的研究提供了新的机会。多物理场建模（例如，有限元代码COMSOL）允许将不同的现象耦合起来，应用复杂的边界条件并求解用户指定的微分方程。在实验方面，图像分析技术，如摄影测量，可以评估位移场并用于数值模型的校准。申请人拟在三个研究项目中应用这些技术。****第一个项目将结合微古生物学和多物理场模型来确定初始或沉积孔隙水盐度对粘土敏感性的影响。微化石组合将被用于估计魁北克Lachenaie遗址的粘土沉积盐度。这些初始盐度剖面将在一个耦合的COMSOL-PHREEQC模型中进行验证，该模型是自尚普兰海撤退以来孔隙流体的化学演化。****在第二个项目中，摄影测量将用于监测实验室中圆形基础引起的变形。基础将建立在人工尚普兰粘土层上，并配有孔隙压力和位移传感器。数码相机将用于拍摄粘土表面变形的照片。位移计算将使用摄影测量软件包VMS。实验数据将用于校准COMSOL中的地质力学模型。****在第三个项目中，COMSOL将用于验证气候变化对尚普兰粘土岩土工程的影响。自2012年以来在Lachenaie收集的孔隙压力数据将使用COMSOL和附近气象站的数据进行建模。基于魁北克南部气候变化模型的边界条件将应用于数值模型中，以评估气候变化对边坡稳定和沉降的影响。****培训熟悉尚普兰粘土的岩土工程师仍然是加拿大东部岩土工程界的首要任务。2010年圣犹达的土流证明了预测尚普兰粘土行为一直存在的困难。这三个项目将引入新的数值分析工具（COMSOL）。这些项目将有助于更好地了解尚普兰粘土的性质，并为现场结构监测提供一系列新的摄影测量方法

Champlain clays underlie a large part of the densely populated Saint Lawrence River valley in Eastern Canada. These clays are known for their high sensitivity to remoulding and their high compressibility. These properties often lead to costly earthflows and large settlements for structures.***Novel experimental methods and numerical modelling tools offer new opportunities in the study of Champlain clays and their geotechnical properties. Multiphysics modelling (e.g., finite-element code COMSOL) allows different phenomena to be coupled, complex boundary conditions to be applied and user-specified differential equations to be solved. On the experimental side, image analysis techniques, like photogrammetry, allow displacement fields to be evaluated and used in the calibration of numerical models. The applicant proposes to apply these techniques in three research projects.****The first project will combine micropaleontology and multiphysics modelling to determine the effect of initial or depositional pore water salinity on clay sensitivity. Microfossil assemblages will be used to estimate the clay depositional salinity for sites in Lachenaie, Quebec. These initial salinity profiles will be validated in a coupled COMSOL-PHREEQC model of the chemical evolution of the pore fluid since the Champlain Sea retreat.****In the second project, photogrammetry will be used to monitor the deformation induced by a circular footing in the laboratory. The footing will rest on an artificial Champlain clay layer instrumented with pore pressure and displacement transducers. Digital cameras will be used to take pictures of the clay surface as it deforms. Displacements will be calculated with VMS, a photogrammetry software package. The experimental data will be used to calibrate a geomechanical model in COMSOL.****In the third project, COMSOL will be used to verify the impact of climate change on the geotechnical engineering of Champlain clays. Pore pressure data collected in Lachenaie since 2012 will be modelled using COMSOL and data from nearby weather stations. Boundary conditions based on climate change models for Southern Quebec will be applied in the numerical model to evaluate the impact of climate change on slope stability and settlement.****Training geotechnical engineers that are familiar with Champlain clays remains a top priority for the geotechnical community of Eastern Canada. The Saint-Jude earthflow of 2010 bears witness to ever-present difficulties in predicting Champlain clay behaviour. The three projects will introduce a new numerical analysis tools (COMSOL). The projects will lead to a better understanding of Champlain clay properties and a new family of photogrammetric methods for structure monitoring in the field.***