This command creates a topsoil definition (.TOP) file which defines topsoil removal and replacement zones to be used in the Process Road Design command. You can have different topsoil adjustments for different station ranges. These adjustments are applied to the existing ground section in the Process Road Design command and will affect the cut and fill volumes. Process Road Design will also report the amounts of topsoil removal and replacement.
The command starts by displaying a list of the topsoil stations in the dialog shown below. To add a topsoil adjustment, pick the Add button which brings up a second dialog. You can have different amounts of topsoil removal and replacement for areas in cut and areas in fill. Subsoil is another category of removal that will be combined with any topsoil removal. The Subsoil removal volume is reported separately from topsoil removal by Process Road Design. Subsoil is automatically removed from the site and not used in fill or as a replacement quantity. Therefore, the subsoil element applies only to unsuitable materials that need to be removed. In the example below, we are only removing topsoil in cut (where cutting must take place in any case), and in the cut, we are removing 2' of subsoil which will be hauled off site (since subsoil is not re-used). The removed 0.5' of topsoil in cut will then be replaced in both cut and fill zones of the road within the limits specified by the "Replacement Limit ID". (No topsoil will be replaced on paved surfaces!)
The Replacement Limit ID is an option to limit the replacement
to occur only within the template left offset Limit ID and the
right offset Limit ID. If this Limit ID is left blank, then the
program will apply the replacement between the left catch point and
the right catch point. Topsoil removal is always applied between
the catch points. The Limit ID corresponds to a template ID as set
in the Design Template routine. Typically, you would use an
ID like SH for shoulder and replace topsoil only from the far left
and right tie/catch points to the SH or shoulder point. If you use
a curb and want to replace topsoil to back of curb, keep in mind
that the program takes the basic code "CB" and creates 3 curb
points typically, so the back of curb would become CB3 in most
L-shaped curbs.
If the Topsoil (".TOP") file is selected within Process Road Design, all quantities of topsoil removal and replacement and subsoil removal are reported, as shown below:
Processing 0+00.00 to 4+42.10
Total Topsoil Removed: 5219.22 C.F., 193.30 C.Y.
Total Subsoil Removed: 20876.89 C.F., 773.22 C.Y.
Total Topsoil Replaced: 5309.57 C.F., 196.65 C.Y.
Hauled-In Topsoil: 90.35 C.F., 3.35 C.Y.
Total Cut : 9106.52 C.F., 337.28 C.Y.
Total Fill: 16402.56 C.F., 607.50 C.Y.
Total SUBGRADE1 - asphalt: 2763.36 C.F., 102.35 C.Y.
Total SUBGRADE2 - stone: 9209.44 C.F., 341.09 C.Y.
Total CURB - concrete: 1078.37 C.F., 39.94 C.Y.
The cut reported in Process Road Design would be the remaining cut after topsoil and subsoil removal, and the fill would be the fill necessary to bring the grade to base of topsoil replacement, on top of which the topsoil is added. The removal of topsoil and subsoil usually creates less cut and more fill, as some of the cut is accomplished by the topsoil/subsoil removal, and in terms of fill, the grade must be brought up to replace the "cavity" created by the topsoil and subsoil removal. Topsoil removal depths and replacement depths can have a dramatic impact on cut and fill quantities, particularly on smaller scale projects like subdivision roads. In this example, every extra 0.1' of topsoil removal produces approximately 100 c.y. of net fill.
Topsoil File to Read Specify a topsoil file.
Topsoil dialog Choose your options.
Keyboard Command: topsoil
Prerequisite: None