A two-dimensional boundary element code, FRACOD$^{2D}$, has been developed to simulate brittle fracturing in rock-like material including fracture initiation, propagation and coalescence under tensile, shear and mixed mode. Since the code is based on the displacement discontinuity solution it is very difficult to implement standard thermo-mechanical boundary element algorithms in its formulation. To simulate the thermo-mechanical process without changing the current structure of the code, an alternative technique has been developed by reconstructing the stress field from other thermo-mechanical models without fracturing process. In this paper an inverse boundary element formulation is presented to reconstruct the complex stress fields by equivalent boundary conditions. Truncated singular value decomposition technique is used for inverse solution. Results from predictive modeling with the reconstructed stresses during the in-situ heater test between the deposition holes are also presented. With successful application, this approach can be a good alternative for modelling fracturing processes under complex loading conditions with boundary elements.s.