An extended finite element method incorporated with the cohesive crack model(CCM-based XFEM) is developed in consideration of crack tip enrichment.It could improve the accuracy and is introduced into dam safety monitoring for the first time.Firstly,the proposed method is verified for a benchmark concrete beam by comparing the results with those of numerical investigations obtained by other researchers.Furthermore,it is adopted as an alternative method for building the deformation hybrid models of non-stable cracks in an arc dam,for the reason that classical FEMs are cumbersome in modeling the cohesive crack growth due to the need of remeshing the moving discontinuities.Case study proves that the fitted results of the mentioned deformation hybrid model,better than the classical statistical model,are well consistent with the measured data and reliable to forecast the development tendency of crack deformation.Therefore,the present CCM-based XFEM could provide a practical way to simulate and monitor the cracking process in concrete arch dam. An extended finite element method incorporated with the cohesive crack model (CCM-based XFEM) is developed in consideration of crack tip enrichment. It could improve the accuracy and is introduced into dam safety monitoring for the first time. Firstly, the proposed method is verified for a benchmark concrete beam by comparing the results with those of numerical investigations obtained by other researchers.Furthermore, it is adopted as an alternative method for building the deformation hybrid models of non-stable cracks in an arc dam, for the reason that classical FEMs are cumbersome in modeling the cohesive crack growth due to the need of remeshing the moving discontinuities. Case study proves that the fitted results of the mentioned damped hybrid model, better than the classical statistical model, are well consistent with the measured data and reliable to forecast the development tendency of crack deformation. Beforefore, the present CCM-based XFEM could provide a practical way to simulate a nd monitor the cracking process in concrete arch dam.