  We explore the electronic structure and topological phase diagram of
heterostructures formed of graphene and ternary bismuth tellurohalide layers.
We show that mechanical strain inherently present in fabricated samples could
induce a topological phase transition in single-sided heterostructures, turning
the sample into a novel experimental realisation of a time reversal invariant
topological insulator. We construct an effective tight binding description for
low energy excitations and fit the model's parameters to ab initio band
structures. We propose a simple approach for predicting phase boundaries as a
function of mechanical distortions and hence gain a deeper understanding on how
the topological phase in the considered system may be engineered.
