Horizontal dimensional drilling method
We handle our job with the usage of the mobile horizontal dimensional drilling rigs made by Ditch Witch and Vermeer. This machinery allows to lay up to eight hundred meters long pipes of steel or polyethylene (up to 70cm Ø) at the depth of about 15 meters when needed. We always monitor the position of the drilling head as well as many other parameters through modern automatic tracking system to control the process in real-time.
Gathering more popularity and demand each year, no-dig technologies are extremely useful to perform next types of works:
- Telecommunications and power network laying,
- Oil, gas, and water tubing,
- Pipe replacement (demolishing old lines and installing new infrastructure at the same time),
- Other drilling activities.
When trenchless technologies are used, the working process is done under the ground for about 90%. It helps to avoid possible damage to near-by roads and other infrastructure elements of the city. There is no need to stop traffic on the roads, what makes trenchless technologies up to 2 times more ergonomic and effective if compared to traditional open method. And it is also much friendlier to the environment.
Detailed info about the horizontal dimensional drilling (HDD) variation of the trenchless layout.
Pilot hole drilling.
Pilot hole drilling is extremely important due to its serious influence on the whole process of trenchless communication building. It is done with the usage of a special formed drilling head having a bevel in the front part and an in-built oscillator.
A flexible driving rod is connected to the drilling head through its hollow shell; it allows to manage the process of the pilot hole drilling in real-time and bypass hidden obstacles in any direction when it is physically possible. Special drilling fluid is pumped into the hole through several slots in the drilling head to create a suspension with shredded ground. The fluid effectively decreases the abrasion of the rod and the head, saves the hole from collapse, maintains low temperature inside the hole, and keeps the tunnel clean pushing the debris to the surface.
The path of the drilling head is captured via special receiving locator getting and analyzing the signal from the transmitter placed inside the head.
The monitors show all visual information about the location, gradient, and azimuth of the drilling head. This info is also duplicated to the drilling head operator’s screen to help the engineering personnel keep the working process under control, check that the penetration path match the project documentation, and minimize the risk of breakdowns and other troubles. If the drilling head goes in the wrong direction, it is stopped by the operator who then solves the problem with all needed manipulations (such as placing the bevel of the drilling head to the right position before drilling rods are dented).
The pilot hole drilling ends when the drilling head reaches the ground surface in the point described in the project documentation.
The following step is the extension of the pilot hole. We put the drilling head off the rod and set up the reamer to broaden the hole. This instrument is pulled through the existing hole back to the drilling rig, widening the pilot hole to the diameter sufficient to lay the pipe. As a rule, the diameter of the extended hole should be 25 to 40 percent wider than the pipe to guarantee smooth final layout.
The pipes are prepared to being laid on the opposite side of the hole from the drilling rig. Then we attach a special head with a reamer and a swivel to the front loop of the prepared pipe set. The swivel is rotating with the drilling road and the reamer without rotating the piping itself. That is how the drilling rig pulls the whole construction through the hole as it is supposed to be done according to the project.
One more factor having extreme importance in HDD workflow is the usage of high-quality drilling fluids at each step of the working process.
Drilling fluid consists of water with special injections, the concentrating and the type of which is determined by the type of soil and the conditions of the penetration.
Common ingredients of the drilling fluid are special clays: bentonites and polymers. Besides, the additives for improvements of the chemical structure of water are widely used to prevent sticking of the ground to the drilling head, rod, and other instruments.