A 10m diameter circular tunnel is to be excavated in a jointed ground.  The joint sets spaced at 6m are dipping towards the West at 50°.  A horizontal circular tunnel is to be constructed approximately parallel to the joint direction.  Occasional near vertical minor fault planes are present in the area.  The depth of the tunnel is approximately 550m and density of rock is 2.5t/m³.

Assume a uniform hydrostatic stress within strata. The rock and joint properties are given in Table 3 below. 

• Using UDEC, model the circular tunnel stability in jointed strata assuming that a single vertical joint intercepts the tunnel.
• Model the tunnel without the support and comment on the results.
• Line the crown of the tunnel (using UDEC commands given), run the model and comment on the results.
• Line the whole tunnel, run the model and comment on the results.
• Design a LOOP within the FISH to automatically install a number of 12m long cable bolts evenly distributed around the tunnel, run the model and comment on the results.