DMT and van der Waals potential for Macroscopic granules

Greetings,

I was wondering if anyone knew how to simply implement the DMT contact
model into Lammps, this simulation would be for micron sized granules
which still experience the van der Waals force. Currently,
granular/hertz/history potential allows for the simulation of the
hertzian contact model. However, it is not possible to use the
colloid potential in conjunction, as when particles come to contact
the force grows without bound. Here I am only interested in the van
der Waals adhesive potential between macroscopic spheres, where

d_0. d_0 is the theoretical interatomic distance, this distance is

what fully defines the van der Waals potential at contact, so that it
is not allowed to grow unbounded as particles come into contact.

In addition, I would like to add a constant adhesive force at contact,
as in agreement with DMT.

If some one knows of an easy fix, to say the colloid and granular
potentials, I would greatly appreciate it.

Thank you,
Eric