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Creep of Geomaterials

Periodic Report Summary 1 - CREEP (Creep of Geomaterials)

Creep of Geomaterials

1 The CREEP project

CREEP is an Industry-Academia Partnerships and Pathways (IAPP) project funded from the 7th Framework Programme (FP7/2007-2013) of the EC under grant agreement PIAG-GA-2011-286397. The research topic of CREEP is time dependent behaviour of geomaterials and its embedment in geotechnical design. The project shall supply tools and knowledge needed in creep analysis of geomaterials through build up of new knowledge and transfer of knowledge between industry and academia. The CREEP consortium consists of two industrial partners, the Norwegian Geotechnical Institute (NGI, Norway) and Deltares (Netherlands) and four partners from academia: Chalmers University of Technology (CHALMERS, Sweden), The Cold and Arid Regions Environmental and Engineering research Institute, Chinese Academy of Sciences (CAREERI, China), Shanghai Jiao Tong University (SJTU, China) and the Norwegian University of Science and Technology (NTNU, Norway). The CREEP network is coordinated by NTNU.

2 Summary of the project objectives:

The project’s overall (S&T) objective is to formulate, implement, and validate a set of novel time dependent material (creep) models for clay, peat, and frozen soil, which allow for enhanced creep predictions in those materials. As model formulation prerequisites experimental quantification of creep behaviour in the respective materials, the latter is a project objective as well. Another main project objective is to demonstrate the applicability of the novel material models via simulating initially simplified benchmark problems, and then moving on to model tests and real case studies. A more detailed overview of project objectives is given in the following work package (WP) overview:

WP 1 Soil characterization. Quantification of creep, through evaluation of literature data and own laboratory test data.

WP 2 Comparison and unification of soft soil creep concepts. Identification of the most relevant model mechanisms in soft soil creep modelling through FE benchmark exercises. Formulation, implementation, verification and validation of a user-friendly time dependent soft clay model relevant to engineering practice.

WP 3 Adoption of existing creep formulations to new materials. Formulation, implementation, verification and validation of industry relevant creep formulations for peat and frozen soils.

WP 4 Model application and recommendations. Validation of all newly created creep models in benchmark problems.

WP 5 Management, knowledge-transfer, dissemination and publicity. Transfer knowledge from the CREEP project to the geotechnical engineering community and the scientific community.

WP 6 Outreach activities. Communication to the general public so as to create awareness for the research performed within CREEP.

3 Work performed since the beginning of the project:

WP 1: Creep properties and mechanisms in clay, peat, sand, and permafrost were characterized and quantified. The characterization was based on available in situ and laboratory tests data and new laboratory test data. A database of laboratory data has been established and will be made publicly available in the near future.

WP 2: Classical creep concepts were compared by defining simple benchmark examples with the purpose of assessing the capabilities of the most common creep formulations through finite element analysis. Development of enhanced creep models for soft soils has been initiated.

WP 3: Development of enhanced creep models for peat and frozen soils has been initiated. First experimental implementations exist to date.

WP 5: One CREEP school and two CREEP workshops have been successfully organized.

WP 6: The first CREEP newsletter has been published

4 Main results so far:

The CREEP consortium has collected high quality laboratory data for characterization of creep and organized these data in a web based database. A novelty in this database is that the influence of sampling method can be easily quantified. By help of well defined creep benchmark problems, requirement profiles for enhanced soft soil (clay and peat) creep formulations have been established and model development initiated. Model development for creep in frozen soil was likewise initiated. However, compared to clay and peat models, the chosen approach for frozen soil is much simpler in structure.

5 Expected final results: (and potential impact)

The CREEP project aims to create a set of novel time dependent material models for clay, peat, and frozen soil, for modelling creep in these materials and the knowledge required so that they can be fruitfully employed in day-to-day engineering practice.

6 Web address of the project: