Influence of Particle Softness and Damage on Engineering Behaviour of Granular Soils

软砂颗粒（例如碳酸盐）由于颗粒接触处的高应力而变形，并导致体积收缩增加、应变软化和液化破坏。发生在地基下的颗粒损伤和破碎、高沉降、打桩、原位测试、大的滑坡和地震也会导致砂土的压缩性和剪切破坏的敏感性。然而，这些颗粒压缩机制在砂和其他粒状土壤的行为中的作用，以及在实验室和现场试验的解释中的作用还没有得到很好的理解，这导致了意想不到的岩土工程危害。因此，除了土壤结构（即细粒含量和密度）外，还需要适当表征土壤颗粒压缩性。在拟议的研究中，将通过以下方式研究砂粒压缩性机制对其行为的影响：（a）微观尺度离散元建模，（B）实验室单元尺度测试，以及（c）宏观尺度现场测试。这些压缩性机制的影响将被集成在土壤本构模型和加拿大实践中使用的先进的数值分析。将从岩土工程文献调查和行业中收集现场试验结果，以建立经验关系，用于预测可压缩砂的行为和状态的现场试验响应。将开发一个新的校正因子，以校正可压缩砂的现场试验结果，从而使用低压缩性砂的广泛解释。这一修正系数将在加拿大的岩土工程设计指南中实施，以实现更安全、更经济的斜坡、地基和地震修复技术设计，并防止意外的灾难性滑坡和故障。目前没有加拿大指南或评论提供任何关于颗粒柔软度和破碎实践影响的指导。拟议的研究计划将培养2名本科生，2名MESc和3名博士生。

Soft sand particles (e.g. carbonates) deform due to high stress at particle contacts and lead to increased volumetric contraction, strain-softening and liquefaction failure. Particle damage and crushing, occurring beneath foundations, high embankments, pile driving, in-situ tests, large run-out landslides, and earthquakes, also contribute to sand compressibility and susceptibility to shear failure. However, the role of these particle compression mechanisms in the behaviour of sands and other granular soils, and in the interpretation of laboratory and in-situ field tests is not yet well understood, which has led to unexpected geotechnical hazards. Therefore, in addition to soil structure (i.e. fines content, and density), soil particle compressibility needs to be properly characterized. In the proposed research, the influence of sand particle compressibility mechanisms on its behaviour will be studied through: (a) micro-scale discrete element modeling, (b) laboratory element-scale testing, and (c) macro-scale field tests. The influence of these compressibility mechanisms will be integrated in soil constitutive models and advanced numerical analysis used in Canadian practice. In-situ field test results will be collected from geotechnical engineering literature survey and industry to develop an empirical relationship for predicting in-situ field test response from the behaviour and state of compressible sands. A new correction factor will be developed to correct field test results in compressible sands, and thus use the wide range of interpretations available for low-compressibility sands. This correction factor will be implemented in geotechnical design guidelines in Canada to achieve safer and more economical design of slopes, foundations, and earthquake remediation techniques, and prevent unexpected catastrophic landslides and failures. No Canadian guideline or commentary currently provides any guidance on the influence of particle softness, and crushing for practice. The proposed research program will train 2 undergraduate, 2 MESc, and 3 PhD students.