  It is shown how a bare three-nucleon force is incorporated into the formalism
of the effective interaction approach for hyperspherical harmonics. As a
practical example we calculate the ground state properties of 3H and 3He using
the Argonne V18 nucleon-nucleon potential and the Urbana IX three-nucleon
force. A very good convergence of binding energies and matter radii is
obtained. We also find a very good agreement of our results compared to other
high precision calculations.

Nuclear Theory