A Geologic Map of Trenchless Suitability for Southeast Missouri

摘要

The sole method of insuring the success of in a horizontally bored utility installation is tornsecure in advance detailed geologic and soil information about the site. A contractor canrnthen be made aware of potential obstacles in the planned path of installation. Soil surveyrnmaps covering individual counties in the United States are available from the UnitedrnStates Department of Agriculture's Natural Resources Conservation Service (NRCS), andrnsurficial materials maps can be obtained from the United States Geological Surveyrn(USGS) and from state geological surveys. These may be used in the planning stages ofrna trenchless installation to determine soil type and variability, depth to bedrock, and otherrnfactors that might limit the feasibility of an installation. None of these maps or any otherrnavailable information from these or other sources specifically addressed trenchlessrninstallation.rnSome needs of contractors, geologists, and geotechnical engineers could be satisfied inrnthe planning stages of a trenchless installation by a map of geology and surficial materialsrnthat is specifically tailored to address factors that influence such installations. Individualrnmaps that delineate areas where a particular method may be used can be prepared.rnHowever, a single map that illustrates all the factors that influence all possible methodsrnwould be of greater use to the contractor who must choose the equipment to be utilizedrnon a specific job site or in a specific geographic area.rnThis paper marks the first time that an overall map of trenchless suitability has ever beenrnattempted. The area mapped by compilation consists of six counties in the southeastrnportion of the state of Missouri and is based on factors that influence the type of methodrnto be used and on factors that help determine the choice of tooling and drilling fluidrntypes, as well as predicted ease of installation. An explanatory text accompanies thernmap The final map is intended to reduce contractor costs by allowing decisions as tornwhat tooling and extras to bring into the field initially, thus eliminating additional trips tornpurchase items or obtain additional tooling and machinery into the field will be reducedrnresulting in a cost savings to the contractor.rnThe final map is intended to reduce contractor costs by helping to ensure proper advancerndecisions regarding tooling, extras, and equipment to be taken to the job site, thusrneliminating the added costs incurred when prior information is unavailable. In addition,rnthe map provides geologists and geotechnical engineers involved in the design processrnwith a rapid source of information for planning decisions.