Reliability-based analysis and design of geotechnical soil-structures and transparent granular soils for geotechnical testing

用于岩土工程测试的岩土结构和透明颗粒土的基于可靠性的分析和设计

• 批准号: RGPIN-2018-04076
• 负责人: Bathurst, Richard
• 金额: $ 4.23万
• 依托单位: Royal Military College of Canada
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=749460
• 关键词: Reliability; based; analysis; design; geotechnical

Reliability-based design and analysis of geotechnical soil-structures is now accepted as the way forward in geotechnical design practice for foundations, retaining walls, reinforced slopes and embankments. Load and resistance factor design (LRFD) is a variant of reliability-based design that has been used in structural engineering design codes since the 1970s. This project will provide engineers with a useful tool for LRFD calibration using spreadsheets and thus avoid Monte Carlo methods that obscure understanding of the contributions of different sources of uncertainty to probabilities of failure. The general approach includes the concept of “level of understanding” that rewards engineers with higher resistance factors for gathering more project data. Candidate applications are steel and polymeric reinforced soil walls and soil-nail reinforced systems. Calibration outcomes for resistance and load factors will be used in future additions of the National Building Code of Canada (NBCC) and the Canadian Highway Bridge Design Code (CHBDC).The random finite element method (RFEM) is a valuable research tool for analysis of reinforced slopes and embankments. It will now be extended to geosynthetic reinforced walls and foundations. The advantage of the RFEM is that it can consider the influence of soil spatial variability on soil-structure performance. The proposed work will investigate non-circular random walk techniques to find the same critical slope failure mechanisms as the RFEM, but with the possibility to avoid excessive computation times. The method will be applied to unreinforced and reinforced soil slopes and embankments, reinforced soil walls and soil nail structures.The first practical transparent surrogate granular soil was invented by the applicant and PhD student Ezzein in 2011. Since that time there has been a proliferation of interest and work investigating a large number of soil-structure interaction problems. A specially manufactured plane strain apparatus that allows the interior of a specimen of transparent soil to be viewed through a transparent membrane will be used in this work. An array of seeded painted targets will be tracked using the digital image correlation (DIC) technique. A laser will also be used to illuminate and track particles in different planes through the specimen using the DIC. These methods will allow the deformation field within a specimen to be observed directly rather than inferred from boundary measurements which is the case using natural opaque sand materials. Different transparent soils varying with respect to particle shape, size and gradation will be investigated. The testing will provide better understanding of the particle-level behaviour of granular soils during plane strain and triaxial testing. Macro-scale stress-strain properties will be available to model the same transparent soils used in centrifuge and 1g bench-scale tests.

基于可靠性的设计和岩土土壤结构的分析现在被认为是基础，挡土墙，增强槽和路堤的岩土设计实践的前进道路。负载和电阻因子设计（LRFD）是基于可靠性设计的变体，自1970年代以来一直在结构工程设计代码中使用。该项目将为工程师提供使用电子表格的LRFD校准的有用工具，从而避免使用Monte Carlo方法，这些方法掩盖了对失败可能性不确定性的不同来源的贡献的理解。一般方法包括“理解水平”的概念，这些概念奖励具有更高阻力因素的工程师，以收集更多的项目数据。候选应用是钢和聚合物增强的土壤壁和土壤钢筋系统。将来的加拿大国家建筑法规（NBCC）和加拿大高速公路桥设计代码（CHBDC）将使用抵抗和负载因子的校准结果。随机有限元方法（RFEM）是用于分析加强插槽和堤防的有价值的研究工具。现在，它将扩展到地质增强的墙壁和地基。 RFEM的优点是它可以考虑土壤空间变异性对土壤结构性能的影响。拟议的工作将研究非圆形随机步行技术，以找到与RFEM相同的临界斜率故障机制，但有可能避免过度的计算时间。该方法将应用于未加固和增强的土壤插槽和堤防，增强土壤壁和土壤指甲结构。2011年，适用的和博士生的Ezzezein在2011年发明了第一个实用的透明替代颗粒状土壤。从那时这项工作将使用透明的膜。将使用数字图像相关（DIC）技术跟踪一系列种子涂漆的目标。激光也将使用DIC通过样品来照明和跟踪不同平面中的颗粒。这些方法将允许直接观察样品中的变形场，而不是通过天然不透明砂材料从边界测量中推断出来。将研究随着颗粒形状，大小和渐变的不同透明土壤。该测试将更好地理解平面应变和三轴测试期间颗粒土壤的粒子水平行为。宏观尺度应力应变特性将用于对离心机和1G台式测试中使用的相同透明土壤进行建模。