Abstract:
In the summer of 2020, construction of a new overflow diversion pipe culvert was needed in the downtown area of the City of Meriden, CT to help minimize chronic flooding. The installation of the large-diameter pipes was to be located only a few feet below two active sets of Amtrak railroad tracks. Empire Paving, Inc. (EPI) was contracted by the City to construct the overflow culverts which consisted of pipe jacking steel casing pipes followed by 60-inch polypropylene pipes. Before jacking could start, site conditions dictated the loose, sandy soils needed to be stabilized ahead of the tunnel boring machine (TBM). Original project specifications called for injection of sodium silicates to stabilize the soil, however a portion of the pipe was to be located below the water table which caused concern with the use of sodium silicates. After further assessment, Acrylamide Chemical Grout from Avanti International was chosen for the purposes of stabilizing the soils and the material’ s cure time. Prior to TBM advancement, steel sheeting was driven at the edge of the tracks. Holes were burnt into the steel sheeting and injection pipes were driven through the holes into the soil. Once the injection pipes were in place, the Acrylamide grout was pumped into the earth face of the break-in – and from inside the tunnel as the TBM advanced - creating an effective grout/soil matrix that strengthened and stabilized the soils. By utilizing Acrylamide grout, the TBM successfully bored through the stabilized soils allowing the culvert pipes to advance without causing issues to supporting soils under the Amtrak rails. Keywords: soil stabilization with grout, soil grouting, acrylamide grout, chemical grout