Alan J. Lutenegger

Determination of Surface Area of Fine-Grained Soils by the Ethylene Glycol Monoethyl Ether (EGME) Method

It is well known that surface phenomena are key factors influencing the behavior of fine-grained soils (FGSs). This paper describes a test procedure for determining the total surface area of FGSs using the ethylene glycol monoethyl ether (EGME) method. The test involves saturating a soil sample with EGME and then removing the excess EGME in a vacuum desiccator, until the EGME forms a monomolecular layer on the soil surface. Results of the test are expressed as specific surface area (SSA), describing the surface area/unit mass of dry soil with units of m-sup-2/g. Test results are presented demonstrating the effect of various test parameters on the results. Results for a number of different FGSs are presented. A detailed recommended test procedure is given. The proposed method uses simple, inexpensive lab equipment, is relatively simple to perform, and allows for rapid determination of SSA.

Specimen Size and Scale Effects of Direct Shear Box Tests of Sands

The direct shear test has survived over the past 50 years in geotechnical engineering applications because of its simplicity and repeatability. Many laboratories perform direct shear box tests on sands to determine the friction angle φ′, or shear strength of the sand for engineering design purposes. However, there are different size shear boxes in use today and the effect of the varying specimen size on the resulting friction angle used in foundation deign has never before been investigated thoroughly. Five sands with different properties were tested in three square shear boxes of varying sizes (60 mm, 101.6 mm, and 304.8 mm), each at three relative densities (dense, medium, and loose). Results of the direct shear tests show that the friction angle φ′ can be dependent on specimen size and that the influence of specimen size is also a function of sand type and relative density. The tests indicate that for well-graded, angular sands, φ′ decreases as box size increases and that the influence of box size is dependent on relative density. The paper provides a description of the test methods and presents the test results.

Determination of Collapse Potential of Soils

A review of various criteria that have been proposed to identify collapsible soils and test techniques, which are used to quantify the amount of collapse, is presented. The results of a series of laboratory single and double oedometer collapse tests conducted on three metastable loess soils are presented to illustrate problems associated with investigating collapse behavior of soils. Guidelines are proposed for developing a standard test procedure.

Stability of loess

Abstract Lutenegger, A.J. and Hallberg, G.R., 1988. Stability of loess. Eng. Geol., 25: 247–261. The natural stability of loess soils can be related to fundamental geotechnical properties such as Atterberg limits, water content and void ratio. Field observations of unstable conditions in loess deposits in the upper midwest, U.S.A. show relationships between instability and the in situ moisture content and the liquidity index of the loess. Unstable loess can attain natural moisture contents equal to, or greater than, its liquid limit. Implications of these observations for applied engineering works are described.

National Geotechnical Experimentation Sites

A system of National Geotechnical Experimentation Sites (NGES) is available in the United States. This program provides easy access to well characterized and documented field test sites with a wide range of geological conditions for the purpose of advancing the state-of-the-art in areas such as in situ testing, instrumentation, prediction of soil behavior and foundation prototype testing. This volume compiles technical information on the following NGES: Treasure Island Naval Station, Texas A&M University, University of Houston, University of Massachusetts at Amherst, Northwestern University and Spring Villa Test Site. Also included are papers describing a spectrum of applications for education and research using the NGES facilities and the associated database. This special publication ends with new directions planned for the NGES program.

Historical Development of Iron Screw-Pile Foundations: 1836―1900

Abstract Beginning around 1836 screw-pile and screw-cylinder elements were used successfully as helical foundations throughout the world to support a variety of large-scale civil engineering structures. Their development and use is largely attributed to engineers from the UK and the USA. The origins and rise of screw-pile and screw-cylinder foundations are reviewed from an historical perspective focusing on the period from 1836 to 1900. A summary of the use of screw-piles as successful foundations for lighthouses, bridges, and piers as well as their use for other engineering applications is given. A description of the common geometries of screw-piles and screw-cylinders during this period is also presented. The information illustrates that helical foundations have been in use for over 170 years throughout the world and can be considered perhaps the single most important development in geotechnical engineering foundation construction of the mid to late nineteenth century.

Compression and Uplift of Rammed Aggregate Piers in Clay

Full scale compression and uplift load tests were conducted on 3 Rammed Aggregate Piers (trademark Geopier) in the upper surficial clay fill at the NGES (National Geotechnical Experimentation Site) located at the University of Massachusetts, Amherst. The tests were conducted to evaluate the performance of this intermediate foundation system in a fine-grained soil. The field investigation also included measurements of vertical and lateral soil deformation to evaluate the active zone of soil resistance. The results show viable uplift and bearing capacity application for the foundation system in fine grained soils. Possible applications include foundation support and/or as a form of ground improvement.

Soil gas transport above a jet fuel/solvent spill at Plattsburgh Air Force Base

We calibrate a stoichiometrically coupled soil gas diffusion model with spatially resolved observations of oxygen, carbon dioxide, total hydrocarbon, and trichloroethylene vapor concentrations in the unsaturated zone above a weathered jet fuel/solvent spill at Plattsburgh Air Force Base in upstate New York. The calibration suggests that aerobic microorganisms in the capillary fringe degrade jet fuel vapor at a steady rate of 9.5 μg hydrocarbons (m−2 s−1). The solvent does not degrade in the fringe, however, and the model and data estimate a steady evaporation rate of 1.2×10−2 μg TCE (m−2 s−1). Barometric pumping slightly alters the steady concentration profile at Plattsburgh, although the transient advective flux is the same order of magnitude as the steady diffusive flux. We derive a simple perturbation theory for the second-order transient concentration corrections and include it in the calibration. The perturbation theory is valid at Plattsburgh because the soil is uniform and permeable with a relatively deep capillary fringe.

Borehole Shear Tests in a Shallow Marine Environment

A wireline adaptation of the borehole shear test (BST) with high-pressure shear plates was one of several in-situ test methods selected to measure strength of overconsolidated phosphatic clays and lime rock at proposed pier locations for the replacement of Sunshine Skyway Bridge, Tampa Bay, Florida. Although the sites soils ordinarily would be determined to be too hard for stage BSTs, an on-site decision was made to try it in lieu of single-point testing to save time. Of 18 stage tests attempted in very hard clay, 10 gave satisfactory failure envelopes, 5 gave envelopes indicative of residual shear strength, and 3 gave invalid envelopes attributed to progressive seating of the shear plates. Stage tests in the harder rocks and shell were less successful. Average cohesion from the 10 satisfactory stage tests in the overconsolidated clays was 91 kPa and the average friction angle Φ = 25.7°. The BST data proved useful for converting a large number of undrained penetration tests into the effective stress strength parameters needed for design. The additional use of special BSTs using smooth plates also permitted site-specific shear strength corrections for soil against steel piles and casings.

Assessing Overconsolidation Ratios in Soil with Piezocone: Referencing Soil Index Properties

AbstractTo enhance the assessment of the overconsolidation ratio (OCR), this paper describes the importance of relating the soil type and soil index properties to the empirical correlations used to evaluate the preconsolidation stress and OCR using the piezocone and the importance to apply the normalized soil behavior approach. Data from a variety of sites is assembled using published and unpublished sources to develop empirical correlations for the normalized soil behavior or the stress history and normalized soil engineering parameter-based approach that vary with the plasticity index, liquid limit, median particle size, and organic content of the soil. Examples are presented to illustrate application of the correlations.