Dry Density (ρd) “Dry Density” (ρd) is a value that represents the density of soil when it is completely dry. To illustrate, it equates to (“bulk density” / 1) + “water content.” This is a common geotechnical engineering laboratory procedure. Dry Density Formula Dry Density = [(Bulk Density ÷ 1) + (Water Content)]

Hooke’s Law “Hooke’s Law” is a geological statement relating to the elastic deformation of rocks.  Hooke’s Law states the strain of an earth-material is linearly proportional to the applied stress.

Regression Regression: In geology, regression is the formation of a specific sequence of sedimentary and metamorphic layers, that are the result of ocean water withdrawing from the land. To illustrate, when regression occurs over millions of years, geologists find a layer of limestone, overlain by shale, and overlain again by limestone. The opposite of regression is…

Rotational Slide (Slump) Definition Rotational Slide (Slump):  A rotational slide is a type of landslide movement that occurs in a turning moment, about a pivot point that is above the center of gravity. This is typically due to an increased normal force on a slope, as well as a reduced cohesion factor of the soil…

De-Watering System in Methane Mitigation De-Watering: In accordance with the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, a de-watering system is a permanent water removal system in a methane mitigation system. In the mitigation process, a de-watering system consists of perforated horizontal pipes, gravel pockets, sump areas with pumps,…

Type Section Geologic Definition In geology, the term “type section” refers to a specific stratigraphic unit, that can be compared to other parts of the geologic unit. For a type section, it’s preferred to describe the location where the geologic unit has the maximum thickness, and where the top and bottom units are observable.