Modelling rainfall-induced mudflows using FEMLIP and a unified hydro-elasto-plastic model with solid-fluid transition

Abstract

The paper describes a proposed unified hydro-elasto-plastic model with a solid-fluid transition. The model associates a hydro-elasto-plastic model for partially saturated geomaterials, a Bingham's viscous law, and the transition criterion between solid and fluid states. The model describes both solid and fluid behaviours of partially saturated geomaterials in a unified framework. In addition, this paper describes a novel Finite Element Method with Lagrangian Integration Points (FEMLIP) formulation for solving hydro-mechanical problems. Based on the equilibrium equation of momentum and the continuity equation of water flow, the formulation was developed and implemented in a FEMLIP tool. Bishop's effective stress expression and proper water retention diagrams were taken into account. A heuristic column and real rainfall-induced mudflows were also simulated and analysed in this study. The permeability effects of partially saturated soil and the effective cohesion were considered, which included consideration of the entire mudflow process. The results were proven satisfactorily in a qualitative fashion.

Real-time monitoring and FEMLIP simulation of a rainfall-induced rockslide

“…Smooth particle hydrodynamics (Cascini et al, 2014) has been used to simulate channelized landslides of flow type; the material point method (Soga et al, 2016;Abe et al, 2013;Marcelo et al, 2016;Bandara et al, 2016) can describe the whole process of landslide movement using hydromechanical coupling; the discrete element method has been used to model the instability of jointed rock slopes (Dong et al, 2015;Huang et al, 2015); and the finite element method with Lagrangian integration points (FEMLIP; Cuomo et al, 2013) has been developed from the particle-in-cell method (Harlow, 1964;Moresi et al, 2002Moresi et al, , 2003 and satisfies the two requirements for simulating the complete evolution of landslides: precise tracking of internal variables and the ability to solve large displacements (Li et al, 2016(Li et al, , 2018a. In contrast to the material point method, the numerical weight of material particles used in the FEMLIP method is updated at each time step, leading to an acceptable calculation cost, owing to the use of an implicit solver (Li et al, 2018a). Each method has its advantages and drawbacks, and for details, the reader can refer to the previous contributions (Soga et al, 2016;Li et al, 2018a).…”

“…In contrast to the material point method, the numerical weight of material particles used in the FEMLIP method is updated at each time step, leading to an acceptable calculation cost, owing to the use of an implicit solver (Li et al, 2018a). Each method has its advantages and drawbacks, and for details, the reader can refer to the previous contributions (Soga et al, 2016;Li et al, 2018a). In this study, the FEMLIP method was used to simulate the rockslide because it overcame the problem of mesh distortion during the large deformation of geomaterials and could easily take into account the normalized global second-order work as a safety factor.…”

Real-time monitoring and FEMLIP simulation of a rainfall-induced rockslide

“…One of the 20 objectives of this study is to present the monitoring of the second rockslide in 2016, and to discuss the adaptability 21 of the monitoring system for rockslides induced by different triggering factors. Lagrangian Integration Points (FEMLIP) method (Cuomo et al, 2013) is developed from the particle-in-cell method 31 (PIC) (Harlow 1964; Moresi et al, 2002;Moresi et al, 2003) and satisfies the two requirements for simulating the 32 complete evolution of landslides: precise tracking of internal variables and the ability to solve large displacements 33 (Li et al, 2016;Li et al, 2018a;Prime et al, 2013). In contrast to the material point method, the numerical weight 34 of material particles used in the FEMLIP method is updated each time step, leading to an acceptable calculation cost, 35 owing to the use of an implicit solver (Li et al, 2018a).…”

“…In contrast to the material point method, the numerical weight 34 of material particles used in the FEMLIP method is updated each time step, leading to an acceptable calculation cost, 35 owing to the use of an implicit solver (Li et al, 2018a). Each method has its advantages and drawbacks, and the 36 details can be referred to the previous contributions (Soga et al, 2016; Li et al, 2018a). In the study, the FEMLIPwith a number of 478-3.…”

responses to all comments

“…Smooth particle hydrodynamics (Cascini et al, 2014) has been used to simulate channelized landslides of flow type; the material point method (Soga et al, 2016;Abe et al, 2013;Marcelo et al, 2016;Bandara et al, 2016) can describe the whole process of landslide movement using hydromechanical coupling; the discrete element method has been used to model the instability of jointed rock slopes (Dong et al, 2015;Huang et al, 2015); and the finite element method with Lagrangian integration points (FEMLIP; Cuomo et al, 2013) has been developed from the particle-in-cell method (Harlow, 1964;Moresi et al, 2002Moresi et al, , 2003 and satisfies the two requirements for simulating the complete evolution of landslides: precise tracking of internal variables and the ability to solve large displacements (Li et al, 2016(Li et al, , 2018a. In contrast to the material point method, the numerical weight of material particles used in the FEMLIP method is updated at each time step, leading to an acceptable calculation cost, owing to the use of an implicit solver (Li et al, 2018a). Each method has its advantages and drawbacks, and for details, the reader can refer to the previous contributions (Soga et al, 2016;Li et al, 2018a).…”