Civil Engineering PE

Answer: D - The width at the top of an excavated varies, depending on the depth and diameter of the installed pipe, local soil type and groundwater elevation, and depth of the frost line. The Occupational Safety and Health Administration (OSHA) sets the safety regulations for trenching and shoring which ultimately defines how trenches are to be sloped, supported, or drained so that workers can safely install waterlines. Generally, local and state design requirements dictate excavated trench widths based on pipe diameters. Waterlines are commonly required to be installed at least 6 inches below the frost line (when applicable).