  We consider exciton-polaritons in a honeycomb lattice of micropillars
subjected to circularly polarized (${\sigma_\pm}$) incoherent pumps, which are
arranged to form two domains in the lattice. We predict that the nonlinear
interaction between the polaritons and the reservoir excitons gives rise to the
topological valley Hall effect where in each valley two counterpropagating
helical edge modes appear. Under a resonant pump, ${\sigma_\pm}$ polaritons
propagate in different directions without being reflected around bends. The
polaritons propagating along the interface have extremely high effective
lifetimes and show fair robustness against disorder. This paves the way for
robust exciton-polariton spin separating and transporting channels in which
polaritons attain and maintain high degrees of spin polarization, even in the
presence of spin relaxation.
