PERMEATION GROUTING KEEP NORFOLK SOUTHERN ON TRACK IN GOSHEN

摘要

In the Spring of 2017, the City of Goshen, Indiana began replacing existing water mains throughout the city as part of the U.S. Hwy 33 Relocation Project. The proposed water main alignment intersected existing Norfolk Southern rail lines at three locations, as well as a single private spur. To avoid interference with rail operations, the use of jack and bore methods were selected for utility installation. A geotechnical investigation revealed adverse conditions for jack and bore installation in the granular soils beneath the tracks. The geotechnical engineer recommended the use of chemical grouting to create a grouted mass prior to the jack and bore operation to prevent track settlement. Nicholson Construction, working under a local contractor, was hired to perform the permeation grouting. Nicholson installed 1,500 total linear feet of tube-a-machete (TAM) pipe and injected 33,000 gallons of chemical grout to complete the work. To avoid existing utilities, the TAM pipes were installed horizontally beneath the tracks along the jack and bore alignment. The chemical grout consisted of sodium silicate, a reactant, and water. The once sandy soil beneath the tracks became a firm mass that would resist cave-in after treatment. Overall, Nicholson completed the permeation grouting ahead of schedule without impacting rail traffic. The following paper will discuss the design and construction of the work and explore the successes and challenges faced along the way.