Abstract：Taking an actual large underground engineering for example，the feasibility of simulating the multi-step excavating，shotcrete and rock bolt supporting for deeply buried wide span tunnel is investigated by using the explicit finite element method. Then，the dynamic responses are investigated under ground shock by nuclear contact surface burst. The analytical results make clear that the programs of excavation and supporting have a large influence on the final plastic strain state of tunnel and a small influence on the displacement state；in addition，the obvious upswell exists on the bottom floor of surrounding rock. For applied depth of burial，the increasing of plastic strain is negligible for applied loading in surrounding rock. It is worthy of note that the axial force of bolts increase to a considerable degree during ground shock；the supporting effect of bolts is necessary to increase the groundshock-resistant ability for deeply-buried wide span tunnel.
