Horizontal directional drilling (HDD) can be an efficient and environmentally friendly way to install underground utilities.

 

However, the process becomes more difficult in varied topography, and as buried pipelines, fiber optics, cable and other types of infrastructure proliferate. To address this issue, HDD equipment manufacturers have developed bore planning software that helps drill operators chart safe courses for their projects.

 

In essence, the software lays the project out on a computer screen, giving the drill operator a visual roadmap to follow from entry to destination. The first programs were introduced about a decade ago, but they have begun to attract strong interest only in recent years, as the programs have become more sophisticated, and as more HDD projects must be executed in heavily developed areas.

 

HDD equipment maker Vermeer Corp. offers Atlas Bore Planner software as its planning tool. The software can be used to plan a bore using any manufacturer’s HDD equipment. It is available for purchase and is offered on a free 14-day trial basis on the company’s Web site.

 

Marvin Klein, a trenchless solutions specialist with Vermeer, demon-strated the program’s capabilities by way of an Internet session on June 10.

 

Walk-around

Atlas Bore Planner is a Microsoft Windows-based tool, compatible with Windows 98, XP and Vista. Two versions are available: Atlas Bore Planner 3 and Atlas Bore Planner Pro. The only difference between the two is that the Pro version lets the user interface with the locating equipment used during drilling.

 

“If you’re using Atlas Bore Planner Pro, and if you’re using tracking equipment that logs the bore as you conduct it, you can download that data into the bore planning profile, and it will show you both the bore plan and the actual bore using the data points collected while drilling,” Klein says.

 

The software has a simple configuration. Six tabs run across the top on the home screen, labeled Job, Topography, Utilities, Targets, Plan and As Built. At the upper right, a toolbar displays a series of tools that can be used to simplify the planning process.

 

As the sequential steps of the bore plan are completed, the lower two-thirds of the screen displays a graphical profile of the bore plan in side view and top-down view.

 

Operation

Klein opened the software and clicked on a Preferences button on the right side of the screen. This menu lets the user:

• Select a language.

• Enter the name and address of the contractor or utility performing the bore.

• Select metric or English units.

• Specify degrees or percent of slope for working with topography.

• Define terms for deflection of the drill pipe (e.g. radius, angles per rod).

 

Klein then opened a Display box, selected a grid, and specified the grid measurements (10 feet per grid line).

 

To begin the bore plan, he clicked on the Job tab at the top of the screen — the only tab highlighted at this stage — and clicked an Add button. This brought up a box in which he entered a job name and specified the entry angle and minimum ground cover. The box also provided a space for entering notes.

 

Next, still working in the Job tab, Klein used a Machine tab to open a box and select the drill to be used for the bore. All Vermeer HDD machines are listed. When he selected the D24x40 Series II machine, a picture of that unit appeared on the left side of the screen, and a box appeared listing that machine’s relevant specifications, including the bend radius of the drill rod (Figure 1). The user can also select Other and bring up a box in which to enter the specifications manually for any make and model of drill.

 

Still in the Job section, Klein clicked the Tooling tab and input the product pipe diameter, quantity and bend radius. “In planning a bore, it is essential to know whether the bend radius of the product is greater than that of the drill pipe,” he said. “If the product pipe doesn’t deflect as much as the drill rod, you need to use that as the limiting factor for planning the bore.” Klein then entered the drill bit and reamer diameters and other tooling specifics.

 

When he closed out of the Job tab, all other tabs on the main screen were highlighted. Klein proceeded to the Topography tab and opened a box for entering topographic data, which normally would come from engineering drawings of the job site.

 

He specified the start point for the bore (0.0), and then a series of other data points, at specified distances from the entry point, to indicate topography changes, such as the top or bottom of a road ditch.

 

He also entered a point 50 feet back from the entry point to represent the setup distance for the drill rig. This process brought up a screen (Figure 2) with grid lines showing a side view of the topography (upper two-thirds of the display) and a top-down view (bottom third).

 

Klein then opened the Utilities tab and again used a box to enter information about buried utilities in the area. For illustration, he added a 4-inch natural gas pipeline running perpendicular to the bore path, 30 feet behind the bore start point, and 38 inches deep, and with a minimum clearance of 24 inches. He noted that utility locations would come from engineering drawings, a one-call service, or potholing and measuring on site.

 

The gas line (Figure 3) now appeared as a yellow dot on the side view of the bore plan with a dotted circle around it to represent the clearance. The path of the gas line also appeared on the top-down view of the site.

 

Next, Klein opened the Targets tab and entered the specific target points that would create the bore profile. As he did this, the side view of the topography remained on screen. As he placed targets, red and blue segments appeared on the bore path, each segment indicating a 10-foot section of drill pipe. When all targets were placed, the screen displayed the entire proposed bore profile (Figure 4).

 

When Klein clicked on the Plan tab, the software did not display the bore plan information. Instead, it displayed a warning, saying that the proposed bore path encroached on the 24-inch minimum clearance around the gas line (Figure 5).

 

After adjusting the bore profile, Klein clicked the Plan tab again. This time the program generated a list of information specific to each individual section of drill rod to be used, including length, distance out, depth, pitch and other data (Figure 6).

 

“This is one of the most beneficial pieces of the program for the driller,” Klein said. “If an operator has to conduct a difficult bore and doesn’t have any hard data to work from, you increase the risk of getting off track. Basically, this data gives him a roadmap.”

 

Klein then demonstrated various features in the toolbar, which include:

• An arrow that allows drag-and-drop addition or movement of target points and allows quick display of data about the target. (He showed how moving a target point too far caused the red-and-blue bore profile line to disappear, indicating that the proposed path would cause the drill rod or product pipe bend radius to be exceeded.)

• A water icon used to add a body of water, such as a stream or pond.

• A utility icon for using drag-and-drop to add various types of utilities (using this function, Klein quickly added a fiber optic cable and sewer pipe to his sample bore profile).

• A skull-and-bones icon for deleting items, such as targets or utilities, from the bore profile diagram.

• A T icon for adding text notes on the diagram.

• A print icon for printing out the entire bore profile, or selected parts of it (topography, utilities, etc.).

 

Observer comments

The Atlas Bore Planner seems to provide a thorough yet simple process for planning HDD projects. One important aspect of drilling — soil and rock conditions — is not included. The operators must glean that information from geological reports and from observations on the site.

 

Apart from that, the tool appears to enable municipal workers or contractors to plan bores with considerable accuracy in a format that a technician could use proficiently with only a limited amount of training.

 

Manufacturer comments

Klein observes that while the Atlas computer program would be capable of accommodating geological information to show underground formations such as rock beds on screen, including such data would be complex due to the variability of geological conditions.

 

At the same time, he says, the bore plans are highly beneficial when drilling in rock because that is where accuracy is essential. “Once you start a rock bore and form the initial bore hole, it is difficult to get back on course should any unforeseen adjustments be necessary,” he says. “But if you go into a rock bore with a plan from this tool already laid out, it will help your operator stay relatively close to the prescribed depths and pitch angles. And then you’re going to be successful in putting the bore where it needs to be.

“The biggest advantage of the tool is that it helps you create a plan before starting a project, and so minimize the element of risk. It’s a very user-friendly program because you can input information in two different ways. You can go into the individual tabs and type the information in, or you can use the icons.”