A Laboratory Study of Soil Creep and Strain-rate Effects of Sands and Aggregates at the Micro-scale

Project: ResearchGRF

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Soil creep is the continuous deformation of soils with time under a constant effective stress. Creep may lead to serviceability problems or even instability and catastrophic failure of foundations, slopes and infrastructures. Even worse is that creep failures are often progressive in nature, which may result in failure of geotechnical structures that are deemed safe in their current state. Breakable sands and sands subjected to a large deviatoric stress fall within the category of highly vulnerable soils against creep problems. This phenomenon has been extensively studied in the literature, however major mechanisms that govern the soil creep have not been systematically investigated or fundamentally understood. Creep of granular materials, at the macro-scale, is linked to the behavior of grains at their contacts including grain-to-grain sliding and grain damage and this behavior is highly strain-rate dependent. The aim of the project is to explore experimentally fundamental aspects of creep of granular materials at the grain scale using novel micromechanical laboratory methods. This study will contribute to develop, for the first time in soil mechanics research, high-quality laboratory data which will lead to quantification and analytical expressions of micro-quantities such as inter-particle sliding friction and stiffness and grain strength and damage against the loading velocity which expresses strain-rate effects. The project will incorporate studies on a variety of soil grain types including naturally occurred soils and aggregates and a variety of load patterns. The first category of soils will predominately involve completely decomposed sand grains and other types of weathered materials which are of major geological and geotechnical interest in Hong Kong as well as carbonate sand grains which find major applications in offshore engineering with particular interest in Southeast Asia. The second category of soils will involve crushed rock and recycled concrete aggregate with major applications in transportation and geotechnical engineering which materials are of particular interest in Hong Kong infrastructure. The project will have a major contribution to the understanding of soil creep mico-mechanisms and will produce data and analytical tools of major impact in soil mechanics research and practice. ?


Effective start/end date1/01/18 → …