Workers operate pipe jacking equipment inside a trench box during a trenchless construction project.

Case Studies

Oncor Fairground Trenchless Rail Crossing

Project Details

Project Name: Oncor Fairground Trenchless Rail Crossing
General Contractor: Larrett, Inc. - Kaufman, TX
Location: Midland, TX
Ground Conditions: Dense sand and stiff to hard clay with varying amounts of gravel and cobbles.
Akkerman Equipment: WM48s-D TBM System, 5200 Pipejacking System, Laser Guideance, 2325B-D Bentonite Lubrication, 524 Haul Unit
Pipe: 48-in Steel Casing
Total Length/Hard Rock Section: 511-LF

Project Overview

Due to the hard geology and tunnel distance, Larrett Inc. used an Akkerman pipejacking system to install this 511-LF, 48-in transmission line under a set of rail tracks. Fitted with a transitional carbide bullet-tipped cutterhead to excavate the dense sands and hard clay, Larrett operators were able to maintain line and grade accuracy with the steerable TBM and laser guidance system.

Challenges

Project required trenchless installation of a 48- in. steel casing under active rail tracks
Subsurface conditions included dense sand and stiff to hard clay with varying amounts of gravel and cobbles
Maintaining precise line and grade over a 511-LF tunnel length was critical due to rail infrastructure overhead
Needed a system capable of withstanding high jacking forces and abrasive geology

Solution

Larrett, Inc. selected the Akkerman WM48s-D TBM System paired with the 5200 Pipejacking System for optimal performance in mixed, challenging soils
Utilized a transitional carbide bullet-tipped cutterhead to handle variable material composition and reduce wear
Employed laser guidance to maintain alignment and a 2325B-D bentonite lubrication system to reduce friction and jacking force
The 524 Haul Unit supported efficient spoil removal, enabling consistent progress across the full 511-LF alignment

Outcome

Successfully installed 511-LF of 48-in. steel casing beneath active rail lines without disrupting rail operations
Maintained line and grade accuracy throughout the entire alignment using laser-guided TBM technology
Overcame challenging mixed ground conditions with consistent progress and minimal delays
Demonstrated the strength and precision of the Akkerman WM48s-D system in a high-stakes, rail infrastructure setting
Delivered a safe, trenchless solution that met both project specifications and owner expectations