Preliminary Feasibility Study of a Ground Modification System for Egress Tunnel Construction.
Wakefield-DC; Curran-JW; Foster-EL
For Reference Only At Bureau Libraries :202 pages
A preliminary systems concept and feasibility study of a ground modification system for egress through rubble has been made. The rubble environment has been postulated to include rock particles ranging in size from gravel to tens of feet in principal dimension. A system has been conceptualized that would store grout components at a safe (deep) level, transfer them to the heading, and inject them into the rubble ahead of the tunnel boring machine (tbm). Crushed muck from the tbm may be stowed in the larger cavities to reduce total grout requirements. Available grouts appear to have many of the properties needed for proper functioning in rubble. The system employs a stinger, a steel tube 15 in. In diameter, which extends through the center of the cutterhead out to a maximum of 35 ft. It carries its own motor and tricone bit and other equipment needed for carrying out the grout injection process. Control of grout envelope position is sensed by geophysical instrumentation and controlled from a remote booth. The preliminary study indicates that the system is feasible, although more detailed studies are recommended.
CP; Final Contract Report;
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