Abstract:The rheology experiment on tufflava was carried out with tunnel of LianYan expressway of Shenzhen, through analysis of test results and model identification, the rheology model was proposed. Based on measured convergence displacement and vault settlement, physical parameters such as elastic modules and creep coefficients were obtained by viscoelasticity incremental back analysis with adaptive genetic algorithm, which were used to predict deformation of surrounding rock. Research results show that mechanical property of surrounding rock can be simulated reasonably with viscoelasticity increment at back analysis with staged construction to predict deformation, which is very important to construction of tunnel.