The HPN model’s design allows
the tunnel’s depth to be minimally
reduced; in some cases the
structures are fixed and not
retractable.
geometry
Static dimensional layout
L = maximum usable length 22,000 mm
P = maximum depth 4,500 mm
HSC = maximum usable height below the tie
beam 6,500 mm
HST = maximum usable height below the
beam 6,100 mm
C = maximum compression = 0 (fixed)
%
= the standard roof slope is 15%