Ditch Cut

The first step performed on a road project is to establish drainage normally through the use of a ditch. To construct a ditch, you must know how to cut a straight ditch line and make sure the ditch line stakes fit the plans.

The first cut to make is the marking cut. The marking cut is a 3- to 4-inch-deep cut made with the toe of the blade (fig. 10-23). The toe of the blade is positioned in line with the outside edge of the front tire. For cutting, the blade pitch is adjusted until the top and bottom edges of the moldboard are aligned

Perpendicular to the ground. The marking cut is a technique used for easier grader control and straighter ditches.

After the marking cut, position the blade at about a 45-degree angle to perform an efficient ditch cut (fig. 10-24). The toe of the blade is positioned in line with the center of the lead tire, while the heel of the blade is raised to allow the windrow to form either inside or outside the rear wheels (fig. 10-25). It maybe necessary to remove the scarifier teeth to keep them from interfering with the blade.

NOTE: Do not forget to lean the top of the front wheels in the direction of the flow of the cut material.

After each ditch cut, the material should be windrowed or spread towards the middle of the road, away from the ditching operations. This technique is called shoulder pickup. To spread the windrow away from the ditch, position the front grader tire on the inside of the windrow. Side shift the blade and the circle so the toe is positioned to the outside of the windrow, as shown in figure 10-26. The heel is positioned to allow the windrow to side cast inside the rear tandem tires. The purpose of the shoulder pickup is to move the windrow away from the foreslope of the ditch.

Figure 10-26.-Shoulder pickup.

The next pass to make is the spreading pass (fig. 10-27). The blade and circle are shifted back under the grader frame. While the grader straddles the windrow, the toe of the blade is positioned inside the front tire, and the heel is positioned to side cast the material outside the rear tandem tires. Depending on the amount of material, the spreading operation may require several passes. After spreading the material, the ditch cut, shoulder pickup, and spreading pass are performed until the desired depth of ditch is completed.

When the backslope of the ditch needs to be cut (fig. 10-28), position the circle and the blade with the heel resting at the bottom of the foreslope, so the material flows inside the right rear tandem tires. The toe of the blade should be forward toward the right front tire. The top of the wheels is leaned toward the backslope. When the ditch is to have a plain V-bottom, you now have to perform a clean-up pass on the foreslope to remove the material from the backslope cut. After the foreslope is clean, perform a shoulder pickup and a spreading pass to finish the ditching operations.

Flat-Bottom Ditch Cut

When a flat-bottomed ditch is required, proceed as follows:

Starting at the foreslope of the original V-ditch (A), as shown in figure 10-29, use the ditch-cutting procedures to cut another V-ditch. After the V-ditch is completed, the next step is to make a flat cut in the bottom of the ditch. This is performed by placing the complete length of the blade in the ditch. The toe is positioned at the base of the backslope (B), and the heel is positioned to side cast the windrow inside the rear

Figure 10-28.-Backslope cut.

tandem tires (C). This operation moves the material to the foreslope of the second V-ditch. To remove the material from the foreslope, perform the procedures used when removing material from a V-ditch.

Crown

The crown, or slope, of the road from the centerline of the road toward the shoulders provides drainage to the ditch. For crowning, angle and adjust the blade to conform to the specified angle of the crown. The material is side tasted in windrows from the shoulders of the road up toward the center line.

When the road has a ditch on each side, make the first pass down the length of one shoulder. When the length of the pass warrants, turn around and proceed down the length of the opposite shoulder with the blade

Figure 10-27.-Spreading pass.

Figure 10-29.-Flat-bottom ditch cut.

Adjustment relative to the same position. When the distance is too short, backup and start on the opposite shoulder with the opposite blade angle adjustment. By repeating overlapping passes made in this manner, you can side cast two windrows from the shoulders to the center line where they are combined into one. The center windrow is then spread with the blade set at 0 degrees. Material spill around the blade ends is spread evenly among the slope of the crown.

NOTE: When grading, the operator cannot obtain a full-visual view of a project site from the operator's seat. For this reason, the operator should stop and climb off the grader periodically to take a visual look at the work area to determine work progress and areas that need attention.