A number of test sites were identified and the waste geomaterials to be used were selected for testing the mechanical and transfer properties. Several soils were selected to cover a wide range of plasticity index, and to be representative of a variety of contexts. For the stabilisers, standardised products like lime or cement, and also stabilisers containing large amounts of by-products from industry, like fly ash and calcium carbide were considered.
The pandemic has impacted the project developpment and several secondments have been canceled vith short notice.
Progress in different work packages:
WP1: Mechanical behaviour of treated waste-geomaterials
WP1 primarily focused on the durability of the mechanical performances of upgraded waste-geomaterials as a function of the context, site conditions, climate, etc. The goal of WP1was to uncover the key mechanisms which control alteration of mechanical properties of upgraded waste-geomaterials in several contexts. The first step of the implementation of the project was the identification and selection of soils, stabilising agents and test sites. An analysis of existing data on a limited number of materials and sites, based on the experience of each partner, was accomplished. Several actions were then defined, each connected to a given context of application / type of material. The actions were connected to:
1. Impact of wetting and drying cycles.
2. Behaviour of lightweight cemented soils.
3. Multiphysical couplings in compacted and treated unsaturated soils.
4. Thermo-hydro-mechanical interaction between the climate and geomaterials.
5. Behaviour of fine-grained soil stabilised with fly ash and alkali activators.
WP2: Durability of transfer performance of treated waste geomaterials
The goal of WP2 was to uncover the key mechanisms which control alteration of transfer properties of upgraded waste-geomaterials in several contexts, in order to develop general recommendations and guidelines to promote durability of transfer properties of upgraded waste geomaterials. The first step of the implementation of the project was the identification and selection of soils, amendments and test sites. The actions in WP2 were:
1. Use of Green Liquor Dregs (GLD) for soil improvement to construct sealing layer. Three sites in Sweden are investigated.
2. Amendment of sulphide bearing soil to mitigate the effect of oxidation.
3. Effect of water percolation on slope stability.
4. Assessment of regulatory barriers to the use of upgraded geomaterials.
5. Design and optimisation of water distribution systems to improve heap leaching.
WP3: Advanced constitutive, physical and numerical modelling
WP3 was focused on developing new constitutive and numerical modelling and decision support tools that can be employed in the analysis, design and construction stages to predict the long-term behaviour of improved waste geomaterials. This WP contributed to the development of solutions and tools to better understand and predict the behaviour of treated waste geomaterials and hence improve/enhance their use in engineering practice.
The first step of the implementation of the project was the identification and selection of soils, stabilising agents and test sites, as well as development of frameworks for the numerical and constitutive modelling tools. The actions in WP3 were:
1. The use of machine learning algorithms to describe the constitutive behaviour of stabilized soils for implementation in a self-learning finite element method (FEM) applied to field testing/monitoring.
2. Experimental, constitutive and numerical modelling of soils stabilized with fly ash, calcium carbide and alkali activators.
3. Effects of chitosan biopolymer on stabilization of sandy soil.
4. Decision support system for the management of excavated waste geomaterials.
