Installing large diameter gravity sewer pipe in Weak Soils, with High Groundwater, and Site Constraints

摘要

Presentation on the planning, engineering, design, and construction using microtunnel technology torninstall over 1,550 linear feet of 42-inch gravity sewer pipe in some of the most challenging geologies in New YorkrnState, including environmental and site conditions.rnGHD was retained to design a 10,000 linear foot, 42-inch gravity-type interceptor sewer to parallel an existingrninterceptor to increase system capacity. The site required four separate trenchless installations to cross InterstaternHighway I-90/790, North Genesee Street, Reels Creek, and Leland Avenue, totalling over 1,550 linear feet. The fourrncrossing sites presented many challenges including low bearing strength soils, weak soils with high organic content,rnhigh groundwater, deep installations, close proximity to high voltage power lines, a constrained site, wetlands, andrnlimited site access.rnGHD launched an extensive soils and hydrogeologic investigation of available trenchless technologies. Given thernsite and pipe service conditions, deep installations, and required accuracy of the gravity sewer installation;rnmicrotunneling and direct-jacking of centrifugally cast fiberglass reinforced polymer mortar (CCFRPM) pipe wasrnultimately selected as the preferred method to complete the crossings.rnGHD was required to coordinate the acceptable means and methods proposed for each trenchless crossing site withrnowners of the property, the right-of-way, and the roadway prior to specifying microtunneling. Constructionrnengineering was also performed to ensure an accurate and well-planned microtunnel submittal would be developed,rnprepared, and executed.rnGHD will present the trenchless crossing selection process as well as critical success factors utilized through thernengineering, design and construction phases.