Quasi-static to dynamic particle simulation

Hello!

I hope to get your suggestions on how I could correctly implement this system of mine. Basically, my simulation is composed of two parts:
1. A granular pile which stand stationary on a light incline, supported by its own bonds. I simulate this use BrittleBeamPrms with a Young's modulus to cohesion ratio of 100:1 (this is to simulate a supposedly cohesionless soil sample with a particle YM of 100MPa). This structure should hold up until an external force is exerted, and should maintain all its bonds.
2. When the external force acts on the granular structure, the bonds are allowed to break and the particles can assume frictional interactions with each other. For this I set to use FrictionPrms.

Now the problem comes at the first part. My particles are rotational, 1mm in size and around 10k of them packed via gengeo. The kinetic energy keeps on rising due to gravity driven motiony which (I believe) eventually breaks the bonds and collapses the structure. I have tried:

    a. applying slightly higher values (relative to air but still in the order of 10-6 Pa.s) of linear damping (LinDampingPrms) and rotational damping (RotDampingPrms). Obviously I cannot increase this much further because it might affect the un-bonded dynamics that come in part 2;
     b. increasing the frictional damping in FrictionPrms, damp = 0.1 to 0.5 (to increase contact energy dissipation, but I'm really not sure if this works since this feature is not included here http://esys.geocomp.uq.edu.au/esys-particle_python_doc/current/pythonapi/html/index.html nor can I find this in the code);
     c. decrease the Young's modulus by 1 to 2 orders of magnitude by virtue of soft-body interactions (ref. https://answers.launchpad.net/esys-particle/+question/552493) as well as the normalK of the walls (ref. https://answers.launchpad.net/esys-particle/+question/242159);
     d. increasing the internal friction angle (in an attempt to stabilize the structure through individual frictional contacts);
     e. re-scaling the sizes and densities (ref. https://answers.launchpad.net/esys-particle/+question/85817 );
     f. decreased my timesteps far below my calculated Courant number (set it to 1e-8 instead of following my calculations of 1e-5).

None of these seem to work. I am now looking at two more options, each of which I have a corresponding question:
1. using HertzianViscoElasticPrms or HertzianViscoElasticFrictionPrms to replace FrictionPrms.
    Q1: Do these interaction groups work well with BrittlBeams?
    Q2: What are the range of values for the damping coefficient A?
2. Simply add LinearDashpotPrms to the BrittleBeams-FrictionPrms combo.
    Q. I've read that this is recommended to be used with NRotFrctionPrms, how about with FrictionPrms?

Please, if any of you have suggestions on what interactions or parameters I could use to solve this problem I would be really grateful.
Thank you very much in advance.

Kahlil