Trenchless Technology

NOV 2018

Trenchless Technology is the premier communications vehicle for the trenchless industry. Through our multiple platforms, readers receive insights into the trenchless industry, as well as keep connected to the latest news, products and projects.

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30 T R E N C H L E S S T EC H N O LO GY N OV E M B E R 2018 N O R T H A M E R I C A N M I C R O T U N N E L I N G 2 0 1 8 R E V I E W CALIFORNIA H EA L D S B U R G Magnolia Force Main Relocation Vadnais Trenchless Services Inc. This project consists of a 310-lf mi- crotunnel drive of 48-in. OD Permalok steel casing with three 16-in. Fused PVC carrier pipes. Shafts for the micro- tunneling will be between 25 and 30 ft deep and will likely be of watertight, sheet pile construction. The microtun- nel will be installed in soils consist- ing primarily of sand and gravel. The tunnel will be approximately 15 to 18 ft below the groundwater table. Crews will use an Iseki TCC1000 Microtunnel (48-in. OD). The work is scheduled to be performed in spring 2019. This tunnel is being installed be- neath Dry Creek, just west of the Rus- sian River and south of the City of Healdsburg . The entire alignment is in granular material (sand and gravel) below the creek bed, yielding a high frac-out risk and there is limited over- head space to work as there are low, overhead powerlines. The microtun- neling work is valued at $795,850. Owner: City of Healdsburg ; Prime Contractor: Terracon Constructors Inc.; Engineer: Mott MacDonald. H U N T I N G TO N B EAC H Feeder No 2 @ Westminster Boulevard Vadnais Trenchless Services Inc. This $737,000 project for the West Orange County Water Board consisted of a 345-lf microtunnel drive of 42-in. OD Permalok steel casing with 30-in. welded steel carrier piping . Shafts for the microtunneling were between 16 and 18 ft deep and were of watertight , slide rail construction. The microtun- nel was installed in soils consisting primarily of weak silt with clay and the potential for peat . The tunnel was approximately 8 ft below the ground- water table. This tunnel was installed beneath the San Diego Freeway (Interstate 405) in North Orange County. The cover beneath the freeway is relatively shallow and there is limited space to work at each end of the crossing . Work began on May 14, 2018, and was com- pleted on July 23, 2018. Prime Contractor: CCL Contracting ; Engineer: GHD, Inc; Equipment : Iseki TCC900 Microtunnel System (42-in. OD). L A J O L L A Gilman Drive Public Sewer Improvement Vadnais Trenchless Services Inc. This $7.6 million project consisted of four separate microtunnel drives of 42-in. Permalok steel casing totaling 3,100 lf. The casings will carry either 21 or 24-in. PVC sewer pipe for the fi- nal liner. Two of the shallower shafts at either end of the project were con- structed using conventional trench shields while the other three deeper shafts were built using steel liner plate and ring beams. The microtun- nels were installed in silty sands and weathered bedrock above the ground- water table. The tunnels were installed from deep shafts in difficult locations with limited space and access in a congest- ed college campus in San Diego. Work started in late-December 2017 and was completed on August 30, 2018. Owner: University of California, San Diego; Engineer: Latitude 33; Equipment : Iseki TCS900 42-in. OD. SA N J O S E Fourth Street 84-in. Interceptor, Phase VI-A Vadnais Trenchless Services Inc. This $1.295 million project consists of a 354-lf microtunnel drive of 84-in. ID (101.5-in. OD) T-lock lined rein- forced concrete jacking pipe. Shafts for the microtunneling will be between 20 and 23 ft deep and will be of wa- tertight , sheet pile construction. The microtunnel will be installed in soils consisting primarily of medium- stiff to stiff clay and some clay with sand. The tunnel will be approximately 10 ft below the groundwater table. This is a design-build contract , very unusual for microtunneling work. This tunnel will be installed beneath US 101 approximately 0.5 miles east of San Jose International Airport . This is an extremely critical stretch of highway in Northern California. The cover beneath the freeway is extreme- ly shallow and required variances from Caltrans. Vadnais is also utiliz- ing a single-pass installation to keep as much cover as possible, which is unusual for highway crossing Work is scheduled to be performed in the first quarter of 2019. Owner: City of San Jose; Prime Con- tractor: Steve P. Rados, Inc.; Engineer: Stantec Consulting Services; Equip- ment: MTS 2430 MTBM (102.5-in. OD). M I C R O T U N N E L I N G J O B L O G 2 0 1 8 Venice Dual Force Main and Venice Pumping Plant Generator Replacement Project

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