Tunnel Construction with Pressed-In Sheet Pile Walls Next to High-Rise Residential Buildings-Paper

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The Kenilworth Tunnel, an 875 m cut-and-cover section of Minneapolis’s Southwest LRT extension, required excavation support beside a high-rise condominium, its parking structure, nearby townhomes, and a freight railway. At the closest point, the parking structure foundations were only 0.6 m from the retaining wall. To limit impacts, the project specified non-impact, non-vibratory installation of approximately 2,500 steel sheet piles, most about 19.8 m long.<br /><br />The team used hydraulic press-in piling, which advances piles by gripping previously installed piles rather than using impact or vibration. An auger attachment (Super Crush Mode) was selected to handle the project’s varied ground conditions, including dense soils. Two machines installed the sheet piles over 14 months.<br /><br />Successful installation depended on matching the piling mode, pile profile and steel grade to the ground and pile length, while controlling the applied press-in force. Some lighter sheet-pile sections were replaced with heavier profiles to improve drivability. A572 Grade 60 steel was selected, and allowable press-in forces were limited to reduce pile deformation and interlock resistance. The project also applied stricter straightness tolerances to long piles, since out-of-straightness can increase resistance or cause installation refusal.<br /><br />The authors conclude that press-in piling can provide a low-noise, low-vibration solution for construction near sensitive structures while installing long piles in hard ground. Its effectiveness depends on careful equipment-mode and pile selection, force control, and verification of pile quality.

Keywords

Kenilworth Tunnel

Minneapolis Southwest LRT

cut-and-cover excavation

sheet piles

hydraulic press-in piling

low-vibration construction

Super Crush Mode

A572 Grade 60 steel

retaining wall support

ground conditions