Contact algorithm error in landslides with unsaturated materials

[lucky3sunny]

I successfully reproduced Case 13 "Slope failure under transient hydraulic loads" from the Anura3D tutorial manual (2025). Then, I made some modifications to the numerical model. The model consists of an unstable sliding mass and a nearly undeformable sliding base (Figure 1), and a contact algorithm was applied between the sliding mass and the base. Unfortunately, I encountered some issues (Figure 2).


The types and parameters of the two materials of the landslide are shown in Table 1

After gravity loading, the contact algorithm is set up between the slider and the slider bed, and the rest of the steps are the same as in the tutorial2025

It is worth noting that if the sliding mass is also set as dry material and the hydraulic conditions are removed, the simulation runs successfully and yields correct results.
Any support you could offer would be greatly appreciated！

[Emily-mathew25]

Hi,
I'm also facing a similar issue while modeling. Could you please share how you resolved it?

[Francisliii]

The value you put under friction of contact property should be the friction coefficient not the interface friction angle.