Descriptors for Bottom Sediments to be Dredged: Summary Report for Work Unit Number 32471.

Abstract : Standard dredging-related geotechnical descriptors are needed so that engineering properties can either be given directly or be readily inferred for engineering applications such as dredgeability. Descriptive terms were developed that are related to a classification system for inferring the dredgeability of in-situ sediments. Also, a knowledge-based expert system (KBES) was developed to provide access to recorded expertise and guidance from experts in their respective fields for use by geotechnical engineers planning a subsurface investigation and by dredging estimators and contractors for interpreting the dredgeability of a proposed dredging project. The KBES GEODREDGE consists of two modules: (a) DREDGABL provides guidance in interpretation of geotechnical properties data for estimating the dredgeability of sediments; (b)GEOSITE contains guidance in the selection of methods and equipment for determining dredgeability. Several Dredging Research Program (DRP) products were identified that were designed to reduce or eliminate adverse impacts of contractor claims of changed conditions arising from incomplete geotechnical information provided to potential dredging contractors. The proposed dredging classification system places all subbottom materials in one of eight groups, each with differing fundamental dredging characteristics.