HDD boring machine is a method of installing underground pipelines, cables and service conduit through trenchless methods. It involves the use of a HDD boring machine, and associated attachments, to accurately drill along the chosen bore path and back ream the required pipe.
HDD boring machines are typically heavy-duty vehicles fitted with track drives, operator controls, and boring machinery. Materials used for pipes include PVC, polyethylene, polypropylene, ductile iron, and steel. The technique has extensive use in urban areas for developing subsurface utilities as it helps in avoiding extensive open cut trenches. The use requires that the operator have complete information about existing utilities so that they can plan the alignment to avoid damaging those utilities. Since uncontrolled drilling can lead to damage, for standardization of the techniques, different trenchless technology promoting organizations have developed guidelines for this technique.
HDD boring is a three stage process:
The first stage consists of drilling a small diameter pilot hole. Drilling fluid is pumped through the drill pipe to the drill head where high pressure jets and the head will grind the soils ahead of the drill bit. The drilling fluid will also carry the cuttings back to the entrance pit at the HDD boring machine.
Location and guidance of the drilling head is an important part of the drilling operation, as the drilling head is under the ground while drilling and, in most cases, not visible from the ground surface. Uncontrolled or unguided drilling can lead to substantial destruction, which can be eliminated by properly locating and guiding the drill head. There are three types of guiding systems for locating and steering the drill head. All three systems have their own merits, and a particular system is chosen depending upon the site requirements.
Walk-over locating system: A sonde or transmitter located behind the drill head registers angle,rotation, direction, and temperature data. An electromagnetic signal encodes this information. Then a handheld receiver on the surface can decode the signal from a sonde or transmitter and the machine operator get the steering directions accordingly.
Wire-line locating system: With a Magnetic Guidance System (MGS), the tool reads inclination and azimuth. This also has a secondary means of location verification that utilizes wire grids laid on the ground surface. This information is transmitted through a wire-line fitted within the drill string. At the HDD boring machine, a navigator performs calculations to confirm the direction and location of the drill head.
Gyro-based locating system: The gyro-based locating system is the most accurate system. It is free of some of the limitations inherent in other systems, such as vulnerability to magnetic disturbance, inability to access areas above a drill path, and a large tolerance of trajectory.
A key to being a successful horizontal directional drilling (HDD boring machine) contractor is finishing every project to specifications on or ahead of schedule.
To achieve that, HDD boring machine must perform efficiently throughout the project without breaking down. Downtime is costly and a contractor repeatedly forced to halt work due to equipment issues not only risks missing completion dates, but can lose future business because of a reputation of unreliability.
Keeping China Horizontal Directional Drilling Machine in top working condition reduces the risk of downtime, but that can be easier said than done. A machine may move immediately from a finished job to another project. On projects where HDD boring machine is working long hours every day, being “too busy” to stop long enough to perform scheduled maintenance can lead to serious problems.
The ways contractors make sure their HDD boring machine stays in good working condition varies greatly. Many large contractors have their own shops and mechanics including a formalized policy and maintenance procedures. Smaller companies may rely on individual crew members responsible for preventive maintenance. However, no matter the size of the company, the number of HDD boring machine it operates, and how maintenance is managed, the goal is the same: keep HDD boring machine drilling and pulling back product.
Dilong construction, has a comprehensive program for maintaining HDD boring machine.
Before each project, our HDD boring machines are taken to the shop and inspected by our mechanics and also inspected by the operator. Any problems are addressed at that time – before the HDD boring machine leaves the yard.
We have a scheduled periodic maintenance program that allows our mechanics to request a time for the HDD boring machines to be serviced based on the recommended hours of operation. Items checked are table slide pads, shuttle arm pads and grips, vice teeth, track tension, chain tension, belts, hoses and overall general condition of the machine.
Routinely checked are track tension; all oils are checked and if any are at the limit on hours, they are replaced; carriage rollers are checked and adjusted; the saver sub is checked for wear; vice jaws are checked for wear; all electronics are checked to make sure they are functioning correctly; and the drill rod is completely washed and cleaned.
Each HDD boring machine is put through basic operations to check functionality and then is sent to a job.
During operation, the condition of drill rod and tooling is inspected before each use or at the time each connection is made. Rods with excessive wear are removed from the string until they can be further inspected. Drill rod maintenance is critical to overall success. This means limiting oversteering the drill rod, using good thread compound every time a joint is connected, and keeping the drive chuck greased and in good condition. A bad or worn drive chuck can ruin every rod in the drill string. Replacing it at the first signs of wear can greatly increase the life of the drill rods.
Cleanliness is next to Godliness applies to equipment, too. Drilling fluids and excess rod grease are washed off daily utilizing the power washer on the vac truck. We always have several weeks in the shop during the winter months where we give all of our equipment a thorough cleaning, buffing and waxing. Not only does it protect the paint from fading, it looks better on the job site and increases the equipment trade-in value. Almost all of our projects are in residential areas. Having nice looking equipment and keeping the job site cleaned up, including sweeping the streets and sidewalks, goes a long way in reducing complaints.
Every morning the China Horizontal Directional Drilling Machine are given a regular safety and maintenance check before operation. This includes everything from fluid checks to safety equipment and operational lockouts to prevent accidental machine damage or harm to personnel due to equipment failure. Details are recorded daily on an inspection form and turned in for review by our maintenance manager and mechanics.
Regular lubrication also takes place at this time. Many of the sites and locations we work at require these checks, and that copies of inspection records be available upon request. It is in Dilong company’s best interest, and the safety and security of our employees, that these checks are completed so that work can be done effectively and efficiently with the utmost concern for safety, followed by productivity.
Winterizing machines and pumps is done every day from November through March, and sometimes earlier. We do this regardless of daily temperature forecasts. It is cheap insurance for those times that the weatherman is wrong.
Anyone on a job has the authority to take a machine out of service for safety concerns. Functionality issues are covered by the operator and the mechanics with management to warrant shutting down a project for repairs or maintenance. In most cases, these decisions are made based upon recommendations of the operator.
On the final pull of a job, all collars and roll pins are checked for cracks and wear. Safety checks also are part of the inspection, including the electric strike alert and limit switches. When a job is completed, HDD boring machines are returned to the yard and washed, inspected, lubricated and the necessary repairs are made. If a rig has been idle for a period of time, before it goes out, the fluids and filters are checked and changed, if necessary, prior to its use.
These practices have extended the productivity of the company’s HDD boring machine.
One of Dilong construction’s HDD boring machines is a 2011 model and still runs with minimal downtime and repairs. Many of our machines have very high hours and require regular maintenance and upkeep just as new ones will. This is the benefit of good maintenance, careful experienced operation and quality products. In spite of the age and hours on our machines, it also helps us to maintain a good reputation on a project because our equipment is capable of completing tasks with minimal breakdowns and repairs.
Dilong construction is experienced in underground and aerial fiber optic, microwave and cellular construction including, but not limited to, horizontal directional boring, excavation, land development, tower, gas, water, electrical and IT work. Dilong construction operates HDD boring machines ranging from 200 to 6000 KN of pullback.
The costs of this operation are orders of magnitude cheaper than microtunneling or directional drilling. As mentioned, no drilling fluids are used other than for lubricating the pipe casings and auger, therefore, reducing the potential impact on surrounding soil.
As the casing is installed at the same time as the auger operation continues, the surrounding soil is held in place by the casing and there is limited opportunity for soil collapse or damage to roads, rail tracks on the surface.
Although the directional steering is limited, the grade of the bore can be accurately set through the alignment of the equipment in the entrance pit. The operation of the horizontal auger boring machine is relatively simple compared to more technological trenchless methods.
This means that less training is required, and the system can be used in developing countries where skilled resources aren't easily available.
Some of the disadvantages of there is very limited ability to steer a horizontal auger boring machine, hence the alignment in the entrance pit is critical to ensure the correct path to the desired exit. Also, horizontal auger boring is not suitable for wet running ground or ground where there is a high frequency of boulders.
Horizontal auger boring is one of the oldest and most successful methods of trenchless construction. Although some newer technologies offer specific advantages in certain ground conditions and in steering ability, horizontal auger boring remains a low cost and highly effective method for many applications.
As this technology continues to advance and improvements made to the steering ability of auger machines, the auger boring machine will remain one of the common methods of trenchless construction for the foreseeable future.
directional drilling under streets, rivers, railway embankments and other obstacles
directional drilling parallel to streets, waters and buildings
Installation of protection pipes
for all kinds of media and pipes the using flexible HDD method
directional drilling in geologically complex terrains up to solid rock
vibration free drainage of dykes, slopes and or dumps using directional drilling
Construction of horizontal drinking water wells or intakes using HDD
using directional drilling, e.g. to stabilise dams
and much more
Horizontal directional drilling (HDD), also known as directional boring, is a minimal impact trenchless construction technique used to install underground pipelines, conduits, cables or any other utility along a predefined path.
Our free guide will provide industry professionals with a deeper understanding of HDD and how to apply that knowledge to trenchless construction.
Drill head φ42mm (Direct connection)
Drill rod, φ42*1828mm
Barel reamer φ 150mm
Reamer φ 200mm
Reamer φ 300mm
Reamer φ 400mm
Power divider/Swivel 10T
Protection joint/Sub saver
Male-female connector/Pull eye