Large Diameter Horizontal Earth Boring Project at Brick Township, NJ
Over the last 45 years auger boring has emerged as one of the premier trenchless technologies primarily for road and railroad crossings. There have been technological advancements over the past decades that resulted in increased bore lengths and the development of large diameter tunneling methods that employ a combination of tunnel boring machines (TBM) and auger boring equipment for improved accuracy and versatility. Auger boring contractor Mr. Leo Barbera of Horizontal Holes has developed new methods and ways to perfect the technology with his years of experience as a manufacturer and contractor.
Project Overview	Figure 1 - Mr. Leo Barbera at Jobsite	Figure 2 -View of pit
Horizontal Holes was contracted to install four 60-inch large diameter steel casings of various lengths for water main installation for road crossings in Brick Township, NJ. While a large portion of the project was open-cut, trenchless technology played a major role in road crossings where open-cut construction would result in disruption of traffic and a great inconvenience to the public.
Productivity
This project achieved impressive productivity rates proving that large diameter tunneling method can be a fast and cost effective technique with a high accuracy needed for gravity sewers and waterlines. The average productivity was 100 ft/day with the highest achieved productivity rate of 140 ft/day.
Installation Process - Bore No. 4 - 120'
Site Preparation
The site offered ample space for boring pits, setting up equipment and stockpiling of materials. The geology of the site consisted of loose clay soil and there was no water logging problems. The entry pit was excavated once the bore path was designed as per the required line and grade. The dimensions of the pit were 40’ long, 15' wide, and 15’ deep. A trench box was installed and sheet piling done to secure the pit and to prevent cave in. The bottom of the pit was concreted in order to provide stability to the boring machine. This is especially important when the project demands high levels of accuracy in line and grade. The boring machine in the pit was laid out in such a way that there was more offset on the side of the bore line (6 ft approx.) where spoil exits the auger to facilitate the removal of spoil by the excavator.
	Figure 3 - Equipment being setup	Figure 4 - Boring operation
Project Details
A large diameter boring machine designed and built by Mr. Leo Barbera of Horizontal Equipment Manufacturing, Inc. powered this project with a CAT 122 HP engine generating 900,000 lbs. of thrust and consisting of three cylinders. A laser guidance system was used to achieve reasonable accuracy of the bore. The cutter head was selected appropriate to the soil condition. The casing was 60-inch steel pipe and 16-inch augers with casing were used to convey the spoil to the pit. The equipment was setup carefully in the pit by the experienced crew and the laser guidance system aligned to the required line. The initial setup is very crucial to the success of any auger boring project. The first section of the casing was attached to the bores head and aligned with the boring machine. Once the required alignment was achieved and the laser beam was on target, the boring was commenced. The lubricant (bentonite) was simultaneously pumped as the casing was installed to provide reduced skin friction. Mr. Leo Barbera stresses the use of bentonite even at the initial stages of installation to achieve an optimal start and easy push of the casing. The bore head can be steered to adjust the line and grade of the pipelines guided by laser beam. The operator’s experience played a pivotal role in achieving a good line and grade.
Project Profile	Machine Specifications
Bore length - 120 ft Casing - 60" /20 ft sections Casing material - Steel Product Pipe - 42" /steel pipes with cement lining Pit Size - 40’ x 15’ x 15’ Lubrication - Baroid Bore-Gel (Bentonite)	Engine Type/HP - CAT/122 HP Transmission - 4 Speed Thrust - 900,000 lbs Emergency shut-off - Yes Centerline - 28" Track length - 34’ (Large diameter) Height - 62" Length - 12’ No. of cylinders - 3