Abstract: This paper gives a numerical analysis for dynamic responses and sliding base-isolation of a building on the ground to an explosion inside one of two-way tunnels. The models of the finite tunnel-included soil zone and the aboveground multi-storey building are formed respectively by means of the eight-node isoparametric finite element technique and mass-lumped system method, and then coupled together to establish the whole interaction one. In the calculating of sliding friction on the base, a modified continuous friction model is proposed in order to overcome the inherent disadvantages of the traditional Coulomb friction model. In comparison with some data under the one-way tunnel condition, example results for responses of an aboveground building with or without a sliding base-isolated measure under blast waves, generated by an explosion inside one of the two-way tunnels and reflected or refracted around the adjacent tunnel, show some new characteristics and isolated effects, which can provide some important references for the related theoretical research and engineering practice.