Is Understanding the Stress History and Behavior of Soft Soils at Risk of Taking a Back Seat?
An important question facing modern geotechnical engineering discipline, and indeed technology in general is, “Do the rapidly advancing fields of information technology and “big data” management encourage engineers to rely less on the fundamentals of our practice?” While there are clearly many benefits of evolving information technology to our field, there is also a compelling case for the necessity of fully understanding basic soil behavior and the uniquely subjective nature of geotechnical engineering.
Building Relationships on Soft Ground…The Story of the Atchafalaya Levees
If only the Atchafalaya levees could talk! These flood protection levees contributed to the professional development of many students and practicing engineers who applied the SHANSEP design methodology to successfully raise dikes constructed on the soft ground of the alluvial and deltaic plains of South Central Louisiana. This paper recounts the accomplishments experienced on these levees as well as the application of the observational design method to other successful applications.
Incorporating pile setup as a factor in determining pile carrying capacity is discussed in this presentation of the research and practices developed by the Louisiana Department of Transportation Development (LADOTD). In addition to a review of the history of pile capacity analysis, the presentation describes the approach presently employed by the LADOTD and assesses the efficacy of this procedure in two case studies.
Phosphogypsum Disposal – The Pros & Cons of Wet versus Dry Stacking
Worldwide, phosphogypsum by-product from a phosphoric acid plant is mostly stacked on land and in some countries (Morocco, Tunisia, South Africa and Mexico) discharged into the sea. More than 200 million tonnes of phosphogypsum are produced annually. Less than 5% of the production is used commercially, primarily for agriculture. This paper focuses on the transport and on-land disposal of phosphogypsum in dry stacks and wet stacks.
Evaluation of Engineering Properties and Wet Stacking Disposal of Widows Creek FGD Gypsum-Fly Ash Waste
Wet stacking of by-product gypsum has been practiced by the phosphate fertilizer industry for decades, and the ability to use wet stacking for flue gas desulfurization (FGD) gypsum had been previously demonstrated. However wet stacking of FGD gypsum containing fly ash had not been previously demonstrated and is the subject of a pilot-scale wet stacking disposal facility operated by the TVA.
Evaluation of Leakage Rates through Geomembrane Liners beneath Phosphogypsum Disposal Facilities
This paper presents a methodology for predicting the quantity of leakage through a defect in a geomembrane bottom liner beneath a phosphogypsum disposal facility. The theoretical basis for the prediction methodology is introduced and then laboratory verification tests are presented and evaluated.
Effects of Phosphate Mining and Other Land Uses on Peace River Flows
During the past twenty years, the Florida phosphate mining industry has made significant improvements in water management and has reduced groundwater withdrawals in the Peace River basin from over 95 mgd in 1980 to less than 20 mgd in 2001.
The entire Florida peninsula is underlain by solution-weathered limestone, with cavities in some areas that are known to exceed 100 ft (30 in) in height and width. The lengths of these natural conduits are measured in miles. The sinkhole-dotted surface of the limestone is typically buried beneath significant thicknesses of overlying sediment, and the foundation hazards associated with building on the limestone generally are not visible from ground level.
The Hole Story: How a Sinkhole in a Phosphogypsum Pile was Explored and Remediated
On June 27, 1994 an erosion sinkhole occurred in the original 200-foot high phosphogypsum stack at the New Wales plant of IMC-Agrico Company (currently Mosaic Fertilizer, LLC). A plan of action was quickly developed and implemented to assess groundwater impacts, to ensure that any contamination was contained on site, to define the extent of the erosion cavity and to undertake appropriate repairs.
Exposing the Underground: A Primer on Subsurface Exploration Techniques
There are few strict codes, thus, geotechnical engineers are required to exercise a significant amount of judgment and they practice according to a regionally variable and frequently changing standard of care.