Resumen de Landslide motion assessment including thermal interaction. An mpm approach
Risk associated with landslides of natural or man-made origin depends on the prediction of the post-failure behaviour of the mobilized mass. Numerical models capable of integrating the landslide geometry and its evolution, the coupled hydro mechanical interaction and the soil properties in the context of dynamic forces and large displacements are currently under development. This thesis is a contribution to this effort.
In this sense, the material point method (MPM) is especially suited for analyzing landslides with large displacements. This numerical procedure must be accompanied by tests under controlled conditions in order to accurately check and calibrate the numerical response.
In this thesis the capabilities of the MPM code developed are evaluated through the modelling of scaled laboratory slope tests with large displacements. In order to achieve an adequate comparison of the experimental and numerical results, the experiments are analysed by means of the interpretation of sequential digital images of the movement of the granular medium during the test (PIV technique). A novel procedure is developed to obtain the field of deformations over time and the tracking of particle path in a manner suitable for comparison with numerical results calculated in MPM.
The main objective of the thesis was the development of a comprehensive calculation tool capable of simulating the behaviour of the slides from the initial triggering to the post-failure phase including thermal effects that determine the evolution of the movement.
A formulation for non-isothermal problems coupled with hydraulic and mechanical behaviour in MPM was developed and implemented. The formulation includes the dissipation of frictional work as heat, which takes place, mainly, in shear bands. The described phenomena are strongly dependent on the thickness of the shear band and this result in a strong dependence of the numerical results in MPM with the discretization mesh. A novel procedure to solve this problem is presented in this thesis.
Finally, very rapid Vajont landslide (Italy 1963) is modelled. A plain strain 2D model is presented without an “a priori” definition of the sliding surface. In fact, in a generalization of previous and recent work, the mobilized materials are not restricted to rigid solids interconnected along a predefined contact surface and the heat generation is not it is limited to a single predefined surface. Thus, thermal interaction processes are developed throughout the model as a function of the location and intensity of deformations.
