A mobile canopy (or rapid advance shield) for use in a tunnel, comprising: first and second opposing and spaced walls; a curved roof coupled between the first and second walls; first and second skis mounted to respective bottoms of the first and second walls, the skis adapted to slide the mobile canopy about a floor of the tunnel; wherein the curved roof slopes downward from a front end of the mobile canopy toward a back end of the mobile canopy, the front end of the mobile canopy for positioning adjacent to a face of the tunnel; wherein the curved roof is movable between a first position proximate a tunnel roof and a second position spaced from the tunnel roof; and, wherein the first and second walls are movable between respective first positions proximate respective tunnel walls and respective second positions spaced from the tunnel walls.