Dikes are currently designed with ultimate strength parameters, or critical state parameters, determined at large strains (25 to 40%). This approach is also used in the WBI calibration. The question remains whether this is the best approach for design. It is certainly not the best approach to back calculate full-scale tests such as the Reevediep and Eemdijk tests.
This research is meant to investigate the idea that in a D-Stability (LEM) package not one strength parameter is used as input, but for each layer the stress-strain curve. This should include also a model to account for stress variations within the geometry and between stages. This would also allow for softening for particular soils.
In a first step strain compatibility is assumed and stability calculations are performed for increasing strain levels until the maximum Stability Factor is reached. From this point on, the failure plane/circle/surface will be frozen within certain limits and softening might lead to lower Stability Factors. This can then be combined with fluctuating water levels as for a normal flood wave or storm, or combined with a residual profile calculation and sequential failures. Finally, it can be investigated if the effect of deformations can be accounted for.
This requires significant programming skills in order to be used in combination with D-Stability, but other LEM software can also be used. Validation can be done by back analysis of the Reevediep and Eemdijk tests and even a comparison with FEM methods, which in the end encounter also problems with accounting for softening.
We are looking for a MSc Geo-Engineering or MSc Hydraulic Engineering student who is interested in dike stability.
During the assignment, you will be part of a team of geotechnical engineers. You will also get the opportunity to:
- Visit different offices of Witteveen+Bos;
- Meet Hydraulic Structures & Geotechnical Engineering colleagues plus colleagues of many other disciplines;
- Hear about our other projects;
- Attend our social events;
- Receive an internship allowance;
- Check for yourself what it is like to work with us.
Supervision
Are you interested in this assignment? Contact the Master thesis coordinator:
