Simulation Of High-speed And Long-runout Landslide With Material Point Method Considering Contact Action

High-speed and long-distance landslides have such characteristics as fast sliding speed,long migration distance,and great destructive force.Its formation mechanisms and movement modes have been increasingly paid attention by scholars around the world.Compared with the traditional numerical simulation methods,the material point method(MPM),which is described by Euler method and Lagrange method,has unique advantages in dealing with large deformation problems.Neither mesh distortion nor convective terms occur in the calculation.Therefore,it is particularly suitable for the simulation of high-speed and long-distance landslides.There is a contact between landslide and landslide bed.When using MPM to simulate landslide,it is necessary to consider the contact between objects and apply contact algorithm to traditional MPM.The Val Pola landslide in Italy,a famous high-speed long-distance landslide,was chosen as an example in this paper to study the application of MPM in landslide simulation.A numerical model was constructed,and the contact between landslide and sliding bed was taken into account.The software Anura 3D₂007.1 was used,which includes the material point contact algorithm,to run the simulation.According to the simulation results,the moving process of the landslide has been discussed.The velocity and displacement of the landslide have been analyzed in detail.The following conclusions can be drawn:(1)The horizontal displacement of the front of the landslide in Val Pola landslide is the greatest,which is about 1400m.The length of horizontal direction after the landslide is about 700m longer than that before the failure.The maximum velocity of the landslide in the front of the landslide is about 56m/s,which is much larger than the lower limit of the velocity of the high-speed and long-distance landslide at present.(2)At the same depth inside the landslide,compared to the rear part,the velocity value and horizontal displacement of the front part is larger.The points which in the same vertical position but different depth,have the similar velocity values and horizontal displacement.(3)The velocity of each part in the process of landslide movement is always changing.Before the landslide collision,the maximum value of velocity in the landslide is found in the front of the landslide.After the collision,the area with the maximum velocity in the landslide shifts backwards from the front part.(4)Throughout the whole simulation,relative position of each monitoring point does not change significantly.There is no sequence movement in the upper,middle and lower monitoring points in the landslide.To some extent,simulation results reflect the phenomenon of "sequence preservation" in the movement of high-speed and longdistance landslide well.