The Canadian geotechnical engineering community has completed a major collaborative 5 year research project entitled the Canadian Liquefaction Experiment (CANLEX). The main objective of the project was to study the phenomenon of soil liquefaction, which can occur in saturated sandy soils and is characterized by a large loss of strength or stiffness resulting in substantial deformations. The intent of this paper is to compare, interpret, and summarize the large amount of field and laboratory data obtained for six sites in Western Canada as part of the CANLEX project. The sites are compared in terms of both flow-liquefaction and cyclic-softening considerations. The paper presents a number of conclusions drawn from the project as a whole, in terms of both fundamental and practical significance.Key words: sand, flow liquefaction, cyclic softening, CANLEX.

A major aim of the Canadian Liquefaction Experiment (CANLEX) was to verify analysis procedures for predicting liquefaction phenomena. Towards this purpose, two loading events were carried out: a field event comprising a clay embankment built over a loose sand foundation layer, and a centrifuge test performed on a model of a sand embankment structure. Both the field event and the centrifuge model were planned so as to induce a static liquefaction failure and were instrumented to observe their response in terms of displacement and pore pressure. The fundamental mechanical characteristics of the foundation layer were determined from laboratory element tests (triaxial and simple shear). These tests formed the basis for the stress-strain modelling used in the numerical analyses. Two fundamentally different modelling techniques were used. One involved a fully coupled plasticity model, and the other involved a model based on a collapse-surface approach. The model and prototype structures were then analyzed and the predicted results in terms of displacements and pore pressures were compared with the measured values. The results from both approaches were found to be in reasonable agreement with the measurements, provided allowance was made for direction of loading and drainage effects were accounted for.Key words: liquefaction, field experiment, embankment, centrifuge model, elastic-plastic model.

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The Canadian geotechnical engineering community has completed a major collaborative 5 year research project entitled the Canadian Liquefaction Experiment (CANLEX). The main objective of the project was to study the phenomenon of soil liquefaction, which can occur in saturated sandy soils and is characterized by a large loss of strength or stiffness resulting in substantial deformations. In many areas of Canada, large structures are constructed on or comprise sandy soils, e.g., some major hydroelectricity earth dams and many tailings impoundments in the mining industry. The behaviour of loose sandy soils can be difficult to predict, but can have a significant financial impact on these types of engineering structures. Consequently, the intent of the CANLEX project was to improve the overall understanding of soil liquefaction. This paper provides an overview of the CANLEX project, outlining the project objectives, major achievements, and conclusions. Four companion papers describe different aspects of the project; thus, together, the five papers provide a summary of the CANLEX project.Key words: geotechnical, liquefaction, CANLEX, collaborative project.