Title: Low Slump Compactive Tail Shield Grouting in Soft Ground, Shield Driven Tunnels

Author(s): John G. Ruggiero

Publication: Symposium Paper

Volume: 83

Issue:

Appears on pages(s): 103-114

Keywords: compacting; grouting; mix proportioning; pressure grouting; tunnels.compacting; grouting; mix proportioning; pressure grouting; tunnels.

DOI: 10.14359/6339

Date: 10/1/1984

Abstract:
Tail void filling of soft ground shield driven tunnels has historically been conducted through the use of pea gravel and neat cement grout. This method has normally resulted in some settlement, infiltration of grout into utilities and divided the Engineer and Contractor on the question of how close to the tunnel heading grouting should be conducted. On the recently completed Red Hook Interceptor Sewer, a soft ground shield driven compressed air tunnel in New York City, a contract modification was made to use a low slump, 5-7 inches (12-18 cm), low shrink grout mixture of cement, limeflour, benton-ite and admixtures in lieu of pea gravel and neat cement grout. Placement was made at two to five times overburden pressures in close proximity to subsurface utilities and into the tail of the shield. Settlement monitoring indicated negligible settlement along the tunnel route. This paper describes the use and advantages of this method.