Engineering—Geologic Studies for Sewer Projects

Realization by Design Engineers that the data presented in test boring logs are often insufficient for accurate estimates and economical designs has led to preparation of more complete engineering-geologic studies for sewer projects. Such studies usually involve a preliminary or planning phase report, followed, if the project is authorized, by a design phase study. These studies involve not only boring logs and test pits, but consideration of geologic factors, the techniques of geophysics and soil laboratory testing, and the use of judgment and experience in discussing the effects of ground conditions, as indicated by all of the data, on the proposed design and construction. Part of the report is presented as an engineering soil map of the project area, and part in the form of a discussion of each soil or rock type mapped and its effect on design and construction.