Landslides : towards more efficient mitigation measures

In the last decade, landslides have caused the death of 20 000 people. These destructive movements of rocks, debris, or earth down a slope are responsible for billions in damage each year. What is more, with global warming and the increase in extreme weather events, predictions suggest these kind of phenomena will only get worse. Yet, mitigation plans are insufficient or unadapted. Indeed, the complexity of the inner phenomena of a landslide, coupled with its interactions with the surrounding constructions and natural environment, makes numerical simulation a challenge. To improve our knowledge of this major natural hazard and for mitigating its disastrous effects, Dr. Alessandro Franci is developing a new and more performant computational tool for modelling landslides. The ultimate goal is to contribute to the design of tailored counter-measures to protect populations.

« Current landslide modelling generally considers the land as a homogeneous medium and the structures affected by the landslide impact as rigid bodies », Dr. Alessandro Franci reports. « The method we are developing will be able both to deal with the heterogeneous nature of the triggered material and to model the effect of this over civil constructions ». The project’s objective is indeed two-fold. On one hand, it seeks to predict the runout dynamics accounting for the complex inner phenomena of a landslide. On the other, it aims to compute the structural damages induced by the impact of the landslide runout against civil constructions and the verification of the resistance of the retaining structure. « It will take into account the soil mechanical properties , the 3D topography- and different types of infrastructures. The data are accessible, we just need an accurate and fast numerical method to compute all this information », the researcher explains.

A hybrid numerical method to model a complex multi-physics phenomenon

To develop a performant computational tool for landslide simulation, Dr. Alessandro Franci plans to associate different existing numerical methods to create a new hybrid numerical method. To conduct his project, him and his team will proceed in consecutive steps. « First, I will focus on modeling the coupling between rigid bodies and free-surface fluids, as the motion of stones and boulders within a mudflow.Then, during my stay in Milan at the ‘Politecnico di Milano’, I will meet up with experts to enhance the constitutive modelling of mudslides . Finally I will work on the impact of a heterogeneous material against infrastructures ». « Once all these developments are implemented , I will focus on one of the project’s biggest challenges, that is to reduce the computational cost of the model ». Running 3D models requires enormous amounts of resources, which translates into extensive amounts of time. « 3D models can take several days to produce results, we need it to go faster ». The last step will be to assess the computational tool’s forecasting capabilities. This will be done using experimental tests realised ad hoc and by simulating of historical landslides events.

Landslides affect every region of the world. It is estimated that 300 million people live in areas prone to them. Accurately simulating landslides, by tailoring models according to the landscape and urban specificities, is crucial if we want to bring vulnerabilities to light and mitigate them. In this sense, Dr. Alessandro Franci’s project holds great promise for the future.