SP-42 Heaving Bedrock Hazards Associated with Expansive, Steeply Dipping Bedrock, Douglas County, Colorado


Background on the heaving bedrock problem, with a focus on Douglas County. Covers methodology and data sources; investigation results on bedrock structure, sedimentology, loading and unloading history, moisture characteristics, engineering properties, damage survey; Dipping Bedrock Overlay District (DBOD) map discussion; heaving bedrock hazards map discussion; subdivision case study; recommendations for land use within the DBOD; conclusions; selected references. 80 pages. 7 tables. 3 appendices. 2 color plates (1:24,000). Digital PDF download. SP-42D

From the Executive Summary:

Heaving bedrock is a distinctive geological hazard that is related to expansive soils. It is more complex than expansive soils in terms of its mechanisms and distribution of deformation, and is capable of causing exceptional damage to houses, roads, and utilities. Heaving bedrock is responsible for tens of millions of dollars worth of damage along the Front Range piedmont of Colorado. In Douglas County alone, several million dollars worth of damage has been incurred since suburban-type development began in the mid-1980s. A large area of undeveloped land in Douglas County is underlain by potentially heaving bedrock. Accordingly, special consideration is warranted for these areas during all phases of site planning and development.