Trenton Biogas Tank Remediation - Releveling and Underpinning-PPT Presentation

PPT Presentation

Pdf Summary

Trenton Biogas’ food-waste recycling and renewable-energy facility experienced significant settlement in its digester and buffer tanks three years after opening. The tanks sit on Holocene salt-marsh and estuarine deposits, including variable layers of peat, organic silt, and clay, with up to 15 feet of compressible soil. Despite prior ground improvement, differential settlement reached about 6.5 inches—nearly twice the 3.4-inch design tolerance.<br /><br />To stabilize and relevel the tanks while keeping the facility operating, the project team selected internal micropiles over compensation grouting, which was considered less predictable. Deep micropiles were installed through the existing concrete slabs and bonded into dense sand. The work included testing the pile and slab connections, temporarily supporting the slabs with jacking piles, lifting them with hydraulic jacks, and filling the resulting voids with grout. The remaining production micropiles were then connected to the slabs.<br /><br />The repairs successfully brought the tanks within settlement tolerances and halted further movement. Final differential elevations were approximately 0.7 inches for one digester, 1.0 inch for the other, and 1.2 inches for the buffer tank. Construction was completed while allowing Trenton Biogas to continue pursuing its production target of 300 tons per day.

Keywords

biogas

food-waste recycling

renewable energy

tank settlement

differential settlement

micropiles

ground improvement

hydraulic jacking

compensation grouting

peat soil