Large Diameter Horizontal Earth Boring Project at Brick Township, NJ

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 technology primarily for road crossings. There have been technological advancements over the past decade that resulted in increased bore lengths and especially the development of bores head method for large diameter installations have improved accuracy and versatility of boring under crossings. Premier auger boring contractor Mr. Leo Barbera, Horizontal Holes International Inc. is a fine example of a contractor embracing new technologies and helping develop new methods and ways to perfect the technology with his years of experience as a manufacturer and contractor.

Project Overview

Recently, Horizontal Holes Int’l Inc 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 bores head method can be fast and cost effective technique with high accuracy needed of gravity sewer and water lines. The average productivity was 100 ft/day with the highest achieved productivity rate of 140 ft/day.

Figure 1 - Mr. Leo Barbera at the Jobsite

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’ high. 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 2 -View of pit showing the machine setup

Project Details

A large diameter boring machine designed and built by Mr. Leo Barbera, 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 reduce 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.

Figure 3 - Equipment being setup

Project Profile

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)

Machine Specification

Manufactured by Horizontal Holes Int’l Inc

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 cylinder - 3