Compensation grouting, or fracture grouting, is the injection of a cement slurry grout, hydrofracturing soil, and creating lenses. The lenses compact the surrounding soil and lift the overlying soil and structures.
Process
Fracture grouting, or compensation grouting, hydrofractures in situ soil using cement slurry grout. A sleeve port pipe is grouted into a pre-drilled hole beneath a structure. The grout is injected under pressure at strategic locations through the ports in the pipe.
Once the hydrofracture pressure of the soil is exceeded, fractures open in the soil and are immediately expanded by the influx of grout. This process results in a controlled heave of the overlying soils and structures.
Specialist contacts
Lucian Spiteri, PE, is a Vice President Pre-Construction at Keller North America.
Lucian has more than 20 years of experience in geotechnical engineering and construction. He holds a Bachelor of Science in Civil Engineering from Manhattan College and has developed deep expertise in ground modification and construction dewatering, including various grouting techniques and systems using wells, wellpoints, and ejectors.
Lucian has contributed to major infrastructure projects such as the Second Avenue, East Side Access, and Number 7 Line Extension in New York City, as well as complex remediation efforts, including a large-scale sinkhole stabilization in Florida and rehabilitation work at the World Trade Center site.
Maxwell Pucciarello, PE, is an Engineering Manager at Keller North America.
Max's role includes oversight and management of Keller's design, estimating, procurement, and QA/QC for specialty grouting jobs, with scopes of work including jet grouting, compaction grouting, rock grouting, and permeation grouting (e.g., cement and chemical). This includes the most complex geotechnical projects, with a wide array of applications, such as temporary and permanent underpinning, bathtub excavations, tunneling, liquefaction mitigation, foundations, support of excavation, and hydraulic barriers.
Max earned a Bachelor of Science degree in Civil Engineering from Rutgers School of Engineering and is a licensed Professional Engineer.
Common uses
- Relevel structures
- Stabilize and mitigate settlement of overlying structures during tunneling
Advantages
- Unobtrusive, as it can be done from shafts or tunnels without access to affected buildings
- Precise control and reporting when linked to an effective monitoring system
Quality assurance
Keller can provide complete solutions which combine fracture grouting with real-time monitoring of affected structures.
Extensive experience has allowed us to develop advanced drilling and computerized grouting systems integrating the grouting injection process and real-time monitoring. Grout injection data is plotted against time and summarized in three-dimensional plots and reports.
Related projects
Infrastructure
No. 7 Subway Line Extension
When incompetencies in the rock were discovered, Keller was contracted to perform several techniques from their tunneling toolbox to keep operations on track.
Infrastructure
Dey Street Connector
The Fulton Street Transit Center was constructed under the New York MTA’s Capital Construction Program to accommodate five subway stations handling nine lines. Keller completed various techniques, including dewatering and remedial grouting.
Infrastructure
Muskrat Falls Emergency Repairs
Keller implemented fracture grouting and compaction grouting to reduce water seepage through the cofferdam to allow construction activities to continue.
Power
Jack Unit II STG Foundation
Keller successfully mitigated the ongoing settlement of the foundation slab of a critical generator unit during peak summer demand without interrupting normal facility operations.
Institutional
Annunciation Church
Keller used techniques previously used for historic structures and real-time monitoring to communicate positive results to the Diocese and maintain the integrity of the historic structure.
