The analysis and evaluation of a highly fractured shoreline rock slope impinging on a residential property

Abstract

A degrading shoreline rock slope impinges on a residential property along the Belleisle Bay, New Brunswick. If no remedial measures are taken, it is anticipated that the building structure will fail. The degradation of the rock slope needs to be reduced to ensure the stability of the deck slabs and the existing structure. This project analyzes and evaluates the rock slope and designs a system of remedial measures that are cost-effective, and do not detract from the natural environment of the site. An evaluation of the site comprises of the identification and analysis of all rock discontinuities and structures in the area. With the generation of a contoured plot of the poles-to-joint-planes the main discontinuities were determined, and with the completion of the analysis, a system of remediation was established. Geotechnical evaluation of the rock slope indicates two dissimilar rock types in the area; jointed volcanic rocks, and highly deformed foliated schist. Four distinct joint sets, along with erosional energy from water and ice, control the behavior of the rock slope, as well as the regional topography. The rock slope has been found to be unstable, with the main process of failure due to the raveling of the slope from freeze thaw action, enhanced by discontinuities. Remedial measures to be taken may consist of drainage, support and protection of the toe of the slope, and some direct application of grout.