A case history of a project involving the installation of soil nails with a connected protective membrane facing as a slope-reinforcement technique is presented. The project involved reshaping of a naturally stable hillside in cambridge, ontario. This slope is formed of very dense glacial till material that was resting at a gradient of 1v:2h, before construction; project requirements necessitated developing the slope at a grade of about 3v:1h. The construction involved the installation of a soil nail reinforcement system to permit thedevelopment of an 18-m-high slope. At the highest point, the upper 12 m of this slope is permanent; the lower 6 m was a temporary slopeexcavated to permit basement construction to proceed. Three slope facing systems were used. In one system a facing of nonwoven geotextile restrained by geogrids tied to the soil nails was applied; a sand, topsoil, and water slurry was injected behind the facing to serve as a void filler and to tension the membrane. In another portion of the slope a geocomposite wall was constructed in front of the soil nail-reinforced slope, and this was tied to the soil nails using geogrid. The third system, which was applied to the temporary slope, consisted of a single membrane of woven geotextile tied to the soil nails with anchor blocks. The reinforced slope has proved to be satisfactory through two winters and two spring thaws. Selection of the soil nail support system for the project was based on economic considerations, and the selection resulted in considerable cost savings for the owner. This paper appears in transportation research record no. 1330, Behavior of jointed rock masses and reinforced soil structures1991
Abstract