2-7. Tunnel Reconnaissance Report Form (DA Form 1250). The DA Form 1250 is used to
report detailed tunnel information obtained from a reconnaissance (Figures 2-7 and 2-8,
pages 2-16 and 2-17). A tunnel reconnaissance determines essential information such as the
serial number, location, type, length, width (including sidewalks), bypasses, alignment,
gradient, and cross section of a tunnel. Information is recorded on the tunnel
reconnaissance report as follows:
Items 1 through 11. Enter all information that establishes positive identification of
the tunnel by route number, route location, map series and sheet number, grid
reference, tunnel number, tunnel type, and geographic reference name. This
portion is self-explanatory.
Items 12 through 17. Enter the overall tunnel dimensions as indicated in
Figure 2-9, page 2-18. Also include this information for any tunnels that branch off
the main tunnel.
Items 18 through 21. Enter the type of lining material, portal material,
ventilation, and drainage. Include in Item 21, any available lighting facilities (if
none, so state).
Items 22 through 29. Enter special considerations, such as whether the tunnel is
chambered for demolition, the date of tunnel completion, and the tunnel's present
condition. Include bypass possibilities; the gradient and passability of approaches;
in-tunnel restrictions; and any geological information pertinent to maintenance,
improvement, or safety.
Items 30 through 32. Draw a plan, a profile, a portal view, and a cross section of
the bore. The plan should include the geographic positioning of the tunnel,
approach routes, terrain features in the immediate area of the tunnel with
emphasis on special features that affect possible bypasses, and tunnel alignment
(including straight sections, angles, and curves). The profile should show the
gradient to and from the tunnel, the gradient of the tunnel floor (designating any
change in grade), and the relation of the tunnel to the terrain through which it
passes. The portal view should show the mouth of the tunnel, the construction
material, its position in relation to the surrounding terrain, and a limited section
of the approach route. The cross section of the tunnel bore should include detailed
information regarding the allowable traffic width, the shape of the bore as it may
affect load heights and widths, and possible man-made or natural obstructions.
Item 33. Include any pertinent information not previously mentioned, and attach
appropriate photographs, if available.