Indication for unsmooth horizon induced by quantum gravity interaction
  The angular ADM reduction of the BTZ spacetime yields a Liouville-type theory. The analysis of the resulting Liouville theory naturally leads to identification of the stretched horizon. The dynamics associated with the stretched horizon has a feature that seems consistent with the unsmooth horizon; the quantum gravity effects are essential for the unsmoothness. We show that the "anomaly" term in the stress-energy tensor is responsible for the Planck scale energy experienced by an infalling observer. 
I. Y. Park
hep-th