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. **

基于可靠度的岩土结构设计和分析，现在被认为是基础、挡土墙、加筋边坡和护坡的岩土设计实践的前进方向。荷载和抗力系数设计（LRFD）是基于可靠性设计的一种变体，自20世纪70年代以来一直用于结构工程设计规范。该项目将为工程师提供一个有用的工具，使用电子表格进行LRFD校准，从而避免蒙地卡罗方法模糊的不确定性的不同来源的故障概率的贡献的理解。一般的方法包括“理解水平”的概念，即奖励工程师收集更多的项目数据。候选应用是钢和聚合物加固土墙和土钉加固系统。阻力和荷载系数的校准结果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。*随机有限元法（RFEM）是分析加筋边坡和加筋土的一个非常有价值的研究工具。它现在将扩展到土工合成材料加固墙和基础。RFEM的优点是可以考虑土体的空间变异性对土-结构性能的影响。本文将研究非圆形随机游走技术，以找到与RFEM相同的临界边坡破坏机制，但可以避免过多的计算时间。该方法将适用于未加固和加固的土质边坡和护坡、加固土墙和土钉结构。**第一个实用的透明替代颗粒土壤是由申请人和博士生Ezzein在2011年发明的。从那时起，人们对土-结构相互作用问题的兴趣和研究工作越来越多。一个专门制造的平面应变仪，允许内部的透明土壤标本，通过透明膜将被视为在这项工作中使用。将使用数字图像相关（DIC）技术跟踪一组种子着色目标。激光也将被用来照亮和跟踪粒子在不同的平面通过使用DIC的样品。这些方法将允许直接观察试样内的变形场，而不是从边界测量中推断，这是使用天然不透明砂材料的情况。不同的透明土壤的颗粒形状，大小和级配的变化将进行研究。试验将提供更好地了解粒状土在平面应变和三轴试验过程中的颗粒级行为。 宏观尺度的应力-应变特性将可用于模拟离心机和1g实验室规模试验中使用的相同透明土壤。 **