Soft Sediment Stability for Beneficial Use: innovative constitutive model development and numerical modelling
Turning fines and soft (dredge) sediments (also so-called unsuitable) to a useful
resource for climate resiliency (e.g. clay for dikes), nature development (e.g. nature
islands), or sustainable human activities (e.g. land reclamation or tailings basin
closure) is a critical opportunity for sustainable development, in the Netherlands
and internationally (as demonstrated by ongoing projects such as Markerwadden,
This project focuses on developing a new constitutive model to assess stability and
failure of soft (dredge or mine tailings) sediment deposits which undergo very large
(fluid-like) deformation. If stable, these deposits will become the substrate for civil
infrastructure (e.g. ports or land reclamation) or nature (e.g. wetlands, islands,
Together with academic, engineering and contractor partners, this project will build
upon state-of-the-art international knowledge and experience to:
- Develop a new constitutive model to appropriately describe the behavior
of soft sediments undergo large deformation, requiring a systematic/critical
literature study as well as developing new theoretical knowledge;
- Embed it into a numerical model that allows for large deformation (i.e.
MPM-Anoura3D); thus, improving the MPM model to a large extend for such
complex applications under discussion;
- Investigate the performance of MPM model equipped with the new
constitutive model against a commercial model (e.g. FLAC) on a laboratory
experiment recently executed in Canada, as an attempt to proof the concept and to
evaluate the readiness of the new model for the future research and commercial
projects in the field of beneficial reuse of soft (unsuitable) sediments.
Doel van het project
In this project we wish to better understand when and under which conditions a soft (dredge) sediments deposit can safely and effectively be used as the substrate for land reclamation natural islands wetland or salt marshes. Specifically we will develop innovative knowledge and tools to assess the stability and failure of a soft sediment deposit when subjected to an external load for example a sand layer. Unlike typical soil soft sediments may undergo significant deformation when exposed to load and before failure expressing fluid-like behavior.Objective of this project is also to develop a tool (constitutive model included in the numerical model MPM) to be added to the “Soft Sediment Toolbox (see Crossover section)” to maximize Beneficial Sediment Use.
Turning fines and soft (dredge) sediments (also so-called unsuitable) to a useful resource for climate resiliency (e.g. clay for dikes) nature development (e.g. nature islands) or sustainable human activities (e.g. land reclamation or industrial waste basin closure) is a critical opportunity for sustainable development in the Netherlands and internationally. Various Dutch and European projects (e.g. Markerwadden Kleirijperij Surricates) and international initiatives (PIANC Working Group (WG) 214 on Beneficial Sediment Use or SedNet WG on Sediments and Circular Economy) are developing and collecting knowledge in this direction.This project focuses on using soft sediments as a substrate for human (e.g. port) or nature development (e.g. natural islands salt marshes and wetland) with specific focus on (sustainable) water and coastal infrastructure (main KIC line) in the context of circular economy and climate change adaptation. Lack of sand pushes land reclamation toward maximizing the use of fines dredge sediments. Likewise climate change and decrease of water quality and biodiversity calls for building (coastal or inland water) islands or salt marshes in front of dikes with locally available (dredge) sediments to improve (secondary KIA lines). Similar knowledge and technologies are applicable to other challenges world-wide such as those in mine activities where huge amounts of industrial waste (i.e. a specific type of soft sediments) is produced as waste. These industrial wastes are generally discharged into large basins which must be eventually returned to nature. One potential solution to this in which the mine industry is investing is to find a way to use industrial waste as substrate for reclamation e.g. forest and or vegetation. Many models have been applied (with success) to 1-dimensional (oedometric) compaction and consolidation problems. In oedometric compaction the deviatoric strain is of the same order of magnitude as the isotropic strain
Activity 1 (A1): Constitutive model development– Industrieel onderzoek.Activity 2 (A2): Embedding it in and testing performance of the new constitutive mode in MPM-Anoura3D– Industrieel onderzoek.The activities will begin in May 2020 with initial focus on Activity 1. The results of Activity 1 will be utilized in Activity 2 which will follow starting in the fall of 2020 to be finalized before the summer of 2021.Activity 1:The existing constitutive models for geotechnical behaviour of soils have deficiencies when applied to soft fine sediments and the deficiencies have the potential to result in unpredicted failures of loads placed on it. In particular the formulations of long-term time-dependent stiffness strength viscosity and large strain behavior are in need of improvement. Hence through a systematic and critical literature study an attempt will be made to:•identify physical processes and their constitutive model elements needed to model large deformation and softening.•investigate to what extent available and suitable constitutive models cover these physical processes and identify the remaining gaps.•prioritize the constitutive model elements that would most improve current modelling on the basis of their likely effect and importance.•to develop based on what have been learned in the above sub-tasks a new formulation of constitutive model aiming to provide the stakeholders with an improved constitutive model for soft fines-dominated sediments that is generic enough to possibly be implemented in various numerical models (e.g. not only MPM-Anoura3D specific) Role of partnersThe sub-tasks under activity 1 will be mainly carried out by Deltares with some considerable contribution of the University of Perugia (Prof. Claudio Tamagnini and his staff). University of Perugia will provide the project with summary of the state of the art of available constitutive models and governing processes. Moreover they will play ad
The currently available geotechnical engineering stability tools are based on soil physics and numerical schematizations that approximate negligible to small deformations in line with most conventional soils. Soft sediments especially soon after dredging and with low to no sand content express physics that resemble fluid-like behavior and undergo very large deformations. Conventional geotechnical models lack the physics specific to this material and generally characterize large deformation as failure. This limits the applicability of beneficial use of soft sediments. Over several years Deltares within an academic-private consortium has been developing a numerical tool (MPM-Anoura3D) to model large deformation with good success. This project intends to build upon this tool (and background knowledge) to include the necessary physical processes specific for large deformation of soft and fine sediments. This project will also utilize experimental tests recently carried out in Canada to verify the performance of the new model. These Canadian experiments and modeling are funded by the Institute for Oil Sands Innovation to bring forward the technology of sand capping of fluid fine industrial waste. This project thus intends to push current available knowledge and tool one step further towards modeling stability and failure of soft sediment deposits with results that can be used for engineering applications.
Alle partijen krijgen alle resultaten van het Project ter beschikking. De resultaten van de samenwerking kunnen breed verspreid worden. Partijen kunnen over deze resultaten vrijelijk publiceren. De resultaten zullen volledig openbaar beschikbaar zijn, met uitzondering van ter beschikking gestelde achtergrondkennis.
De informatie over dit project wordt kenbaar gemaakt via de website van de TKI Deltatechnologie (projectbeschrijving) en de projectwiki van Deltares (projectvoortgang en resultaten).
Na de datum waarop deze Overeenkomst in werking is getreden, maar uiterlijk tot een jaar voor de beoogde datum waarop het Project zal zijn voltooid, kunnen ondernemers en/of onderzoeksinstellingen, die op het terrein van het relevante subsidieprogramma van het TKI werkzaam zijn alsnog als Partij toetreden. Een later toetredende Partij zal een nader overeen te komen bijdrage in kind en/of in cash moeten leveren die in redelijke verhouding staat tot zijn relatief aandeel in het Project na toetreding. De overige Partijen ontvangen vervolgens naar rato een terugbetaling en/ of gedeeltelijke vrijstellingen van hun nog te leveren bijdrage in kind, voor zover niet besloten wordt de bijdrage van de later toetredende Partij aan het projectbudget toe te voegen.