Compactive Prestress in Shales

Research Article| August 01, 1981 Compactive Prestress in Shales C. WILLIAM LOVELL; C. WILLIAM LOVELL Department of Civil Engineering, Purdue University, West Lafayette, IN 47906 Search for other works by this author on: GSW Google Scholar GARY R. WITSMAN GARY R. WITSMAN Soil Testing Services, Northbrook, IL 60062 Search for other works by this author on: GSW Google Scholar Author and Article Information C. WILLIAM LOVELL Department of Civil Engineering, Purdue University, West Lafayette, IN 47906 GARY R. WITSMAN Soil Testing Services, Northbrook, IL 60062 Publisher: Association of Environmental & Engineering Geologists First Online: 02 Mar 2017 Online Issn: 1558-9161 Print Issn: 1078-7275 © 1981 Association of Engineering Geologists Environmental & Engineering Geoscience (1981) xviii (3): 297–308. https://doi.org/10.2113/gseegeosci.xviii.3.297 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation C. WILLIAM LOVELL, GARY R. WITSMAN; Compactive Prestress in Shales. Environmental & Engineering Geoscience 1981;; xviii (3): 297–308. doi: https://doi.org/10.2113/gseegeosci.xviii.3.297 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract The term shale encompasses materials displaying different responses during excavation, compaction and service life. A soft, non-durable shale is easily broken down and may be Compacted as a soil fill. A hard, durable shale may perform satisfactorily when placed as a rock fill. An intermediate shale may be mechanically hard during excavation and compaction but may prove to be non-durable over the service life of a compacted embankment. The New Providence shale used in this study is classified as a medium hard, non-durable shale.Shale samples were compacted from shale aggregate by a California kneading compactor. Conventional oedometer tests were performed on a group of as-compated samples to investigate the compressibility behavior and the compactive prestress induced in the samples. At pressures above the prestress the compressibility of the compacted soil markedly increases. The effect of the compaction variables on the observed behavior of the samples was of interest. These variables were: compacted dry density, molding moisture content, initial void ratio, initial degree of saturation, and nominal compactive pressure.It was found that the prestress was equal to the compaction pressure for the low and intermediate compactive efforts at the dry-of-optimum and near-optimum moisture conditions. Increasing the compaction pressure or the moisture condition resulted in a decrease in the ratio of prestress to compaction pressure to less than unity. Increasing moisture reduces the air permeability and permits the buildup of pore air and pore water pressures during compaction which results in less of the compaction pressure being applied to the soil skeleton. Increasing compaction pressure causes greater aggregate degradation during compaction. Some of the compaction effort is spent breaking aggregates which results in the reduction in the number of large pores.Statistical analysis of the accumulated test data permitted a descriptive model to be developed for the estimation of the compactive prestress for samples of compacted New Providence shale. The most influential variables affecting the level of compactive prestress appear to be the nominal compaction pressure and the molding moisture content. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.