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

用于岩土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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=644790
• 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. **

基于可靠性的岩土结构设计和分析现已被认为是地基、挡土墙、加筋斜坡和路堤岩土工程设计实践的前进方向。荷载和阻力系数设计 (LRFD) 是基于可靠性的设计的一种变体。自 20 世纪 70 年代以来一直在结构工程设计规范中使用，该项目将为工程师提供使用电子表格进行 LRFD 校准的有用工具，从而避免使用蒙特卡罗方法来模糊对不同来源的贡献的理解。一般方法包括“理解水平”的概念，奖励工程师收集更多项目数据的阻力系数。候选应用是钢和聚合物加固土墙和土钉加固系统。阻力和荷载系数将用于加拿大国家建筑规范 (NBCC) 和加拿大公路桥梁设计规范 (CHBDC) 的未来补充。******随机有限元方法 (RFEM) 是一种有价值的研究工具用于分析加固斜坡和现在将扩展到土工合成材料加筋墙和地基，RFEM 的优点是它可以考虑土壤空间变化对土壤结构性能的影响，以找到相同的非圆形随机游走技术。临界边坡破坏机制与 RFEM 相同，但可以避免过多的计算时间。该方法将应用于未加筋和加筋土坡和路堤、加筋土墙和土钉结构。******第一个实用的透明方法。替代颗粒土壤是申请人兼博士生 Ezzein 于 2011 年发明的。从那时起，人们对大量土壤-结构相互作用问题的兴趣和工作不断增加。一种专门制造的平面应变装置，允许内部结构。这项工作将使用通过透明膜观察的透明土壤样本，并使用数字图像相关（DIC）技术来跟踪一系列带有种子的着色目标。飞机经过这些方法将允许直接观察样本内的变形场，而不是从边界测量中推断出不同的透明土壤的颗粒形状、尺寸和级配。该测试将更好地了解颗粒土壤在平面应变和三轴测试过程中的颗粒级行为，可用于模拟离心机和 1g 中使用的相同透明土壤。实验室规模测试。