Question $1(25$ marks$)$

An $8$ m tunnel with dimension as shown in Figure Al is to be excavated by drill and blast method at a depth of $50$ m below ground.

After blasting, a geologist mapped the face with the rock condition shown in Figure A$2.$

The conditions of the joints can be summarized as follows:

$\backslash$begin$\{$tabular$\}\{|$c$|$c$|$c$|$c$|$c$|$c$|$c$|\}$

$\backslash$hline Type & Dip $/$DIp Direction & Spacing $($mm$)$ & $\backslash$begin$\{$tabular$\}\{$l$\}$

Persistence $\backslash \backslash$

$($m$)$

$\backslash$end$\{$tabular$\}$ & Roughness & Aperture $($mm$)$ & Infiliting $\backslash \backslash$

$\backslash$hline J$.$ & $85.\backslash (1440^\{\backslash$circ$\}\backslash )$ & $100-1000$ & $\backslash (>6\backslash )$ & Smosth blanar & $\backslash (0-2\backslash )$ & $\backslash (\backslash$mathrm$\{$Fe$\}^\{+\}\backslash )$stained $\backslash \backslash$

$\backslash$hline $\backslash ($ J$\_\{2\}\backslash )$ & $85\backslash \%\backslash (1110^\{\backslash$circ$\}\backslash )$ & $\backslash (100-300\backslash )$ & $\backslash (>6\backslash )$ & Simsoth planar & $0-2$ & charite$/$uDalas a $\backslash \backslash$

$\backslash$hline Js & $\backslash (80^\{\backslash$circ$\}/020^\{\backslash$circ$\}\backslash )$ & $200-800$ & $\backslash (>6\backslash )$ & Simooth Planar & $\backslash (0-2\backslash )$ & $\backslash (\backslash$mathrm$\{$Fe$\}^\{+\}\backslash )\backslash \backslash$

$\backslash$hline $\backslash ($ J$\_\{4\}\backslash )$ & $\backslash (10^\{1\}\backslash \%\backslash )$ & $\backslash (200-800\backslash )$ & $\backslash (>5\backslash )$ & Swooth planar & $0-2$ & stained $\backslash \backslash$

$\backslash$hline

$\backslash$end$\{$tabular$\}$

It will be a railway tunnel, concrete$-$lined within $2$ years after excavation, and the rock is granite with UCS greater than $\backslash (70\backslash$mathrm$\{$MPa$\},\backslash$mathrm$\{$RQD$\}\backslash )$ is $65$ and dry.

It will be a railway tunnel, concrete$-$lined within $2$ years after excavation, and the rock is granite with UCS greater than $\backslash (70\backslash$mathrm$\{$MPa$\},\backslash$mathrm$\{$RQD$\}\backslash )$ is $65$ and dry.

Assume $\backslash (\backslash$mathrm$\{$ESR$\}=1\mathrm{.}3\backslash )$ for tunnel and $\backslash (\backslash$mathrm$\{$SRF$\}=2\mathrm{.}5\backslash ).$

Based on this information, estimate the Q value of this mapped face and provide the support class, bolt length and unsupported span for the crown and wall based on the chart in Figure A$3$:

$4)$ Systematic bolting. $($and unreinforced shotcrete, $4-10$ cm $)$ eirforced nos or mowcreve and porung

$5)$ Fibre reinforced shotcrete and bolting. $\backslash (5\mathrm{.}9\backslash$mathrm$\{$~cm$\}\backslash$quad $\backslash )9)$ Cast concrete lining

E$)$ Energy absorption in fibre reinforced shotcrete at $25$ mm bending during plate testing

D$55\backslash \%$ Reinforced shotgrete ribs: $6$ reinforcement bars in double layers in $55$ cm thick ribs with certre to centre $($oic$)$ specing $1\mathrm{.}2$ m

cic $1\mathrm{.}2$ Each box corresponds to $\backslash ($ Q $\backslash )-$values of the left side of the box, as indicated.

Figure $2-$ Updated Q$-$chart $($Grimstad et al$,2003)$

Figure A$3.$ Design Support Class

Provide justification or assumption for each parameter you selected and show your calculation and support class in Figure A$3.$