Simulation of the mechanical response of a soil mixing type material using image analysis and a treated material behavior model

Back to the list of projects
img projet

Name of the project : Simulation of the mechanical response of a soil mixing type material using image analysis and a treated material behavior model

Type of project : Internships

Summary:

Dikes are civil engineering works that play an essential role: they protect populations and their property in the event of flooding. However, if this function fails, that is to say when a dike breaks completely, the human and economic consequences can be dramatic. In a context of climate change, aging flood protection structures must be monitored and reinforced in order to ensure that an adequate level of protection is maintained. In addition, the evolution of the long-term properties of the constituent materials of dikes must be evaluated in terms of temperature and water content as a function of parameters such as the initial conditions at the time of events such as floods.

Reinforcing through “soil mixing” (mixing instead of cement and soil to form a vertical panel in the body of the dike) is one techniques used for certain dikes along the Loire.

The main objective of this research will be to provide ways of obtaining a homogenized material using imaging methods adapted to the problem. As such, the imagery aspect of the project will be based on two approaches:

  1. – Use of existing photos to establish a database of possible shapes in order to create a virtual microstructural medium. Secondly, numerical simulations will make it possible to determine the hydraulic and mechanical properties of the materials containing the inclusions;
  2. – 1 cm slices of a cylindrical sample and successive photos of each slice to produce a 3D model, calculate the hydraulic and mechanical properties of materials with inclusions and above all compare them with the measurements taken of nearby samples.

The influence of the percentage of the untreated surface, the number, shape and spatial distribution of the inclusions on the response of the material (mechanical and hydraulic) will be studied based on numerical simulations that seek to best model this discontinuous material by the method of discrete elements. Several forms of meshes can be tested.

The work program will consist of the following stages:

  1. Carrying out an image analysis of the samples available for a Deep soil mixing site;
  2. Choosing the parameters of the different materials from the tests carried out and from the literature;
  3. Carrying out simulations to determine the behavior of the material treated as a whole;
  4. Validating the model based on site data.

Name of supervisor(s) : Alain Le Kouby, Myriam Duc et Christophe Chevalier (GERS, UGE Marne-la-Vallée) ; François Willot et Petr Dokladal (CMM, Ecole des Mines ParisTech) ; Eva Dokladalova (LIGM, ESIEE Paris)

Name of student(s): Louis LEPRINCE (Université Paris-Saclay)

Start and end of the project : 28 April 2021 - 28 September 2021

Duration : 5 months