Wu T.H.,Ohio State University |
Gale S.M.,01 Twelve Oaks Center Dr |
Zhou S.Z.,Terracon |
Geiger E.C.,Office of Geotech. Engineering
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2011
A geotextile-reinforced embankment was built over soft ground. Staged construction and vertical prefabricated drains were used to obtain strength gain via consolidation of the foundation material. Settlement and pore pressure were measured as a part of construction control. Settlement, differential settlement, and rate of consolidation were predicted by simple models. Uncertainties in the predictions were evaluated to assess the reliability of the predictions. The estimated errors were compared with the measured values, and major contributors to prediction errors were identified. © 2011 American Society of Civil Engineers.
Shu S.,Terracon |
Muhunthan B.,Washington State University |
Li X.S.,Hong Kong University of Science and Technology
International Journal of Geomechanics | Year: 2011
This paper presents a state-dependent constitutive model for sand formulated within the critical-state framework and its implementation into a numerical analysis (FLAC3D) program. The implemented model was verified by using drained triaxial results on sands. The proposed model is shown to capture the stress path dependent behavior of sand over a wide range of densities and confining pressures well based on a unique set of parameters. Numerical simulations of the behavior of a micropile under vertical loading shows that the side and tip resistance, and thus the total resistance of the pile, are functions of the "in situ state" of soil as defined by the state parameter ψ=e-ec in which e is the void ratio and ec the void ratio at the critical state. © 2011 American Society of Civil Engineers.
Yang L.C.,Regional Manager |
Jordan M.,Terracon |
Geotechnical Special Publication | Year: 2016
A former foundry operation and service station in northern Illinois is impacted with polycyclic aromatic hydrocarbons (PAHs) in soil. Site characterization and statistical analysis identified three PAHs-benzo(a)pyrene, benzo(b)fluoranthene, and dibenzo(a,h)anthracene-with concentrations exceeding their site specific remedial objectives in the upper three feet of soil. Project funding was not sufficient to allow for immediate site cleanup via excavation. Thus, a sustainable design was devised that relies on a combination of phytoremediation and potential limited hot spot removal in conjunction with institutional controls. In an effort to accommodate site specific challenges and short remedial timeframe of less than three years, a unique approach predicated on succession crops was developed. © ASCE.
Huang J.,University of Texas at San Antonio |
Bhandari A.,Terracon |
Yang X.,Louisiana Transportation Research Center
Geotechnical Engineering | Year: 2011
Nowadays geosynthetics have been used as a routine reinforcement in earth structures such as mechanically stabilized earth (MSE) walls, column-supported embankments, soil slopes, and paved/unpaved roads. In those applications, reinforcement mechanisms of the geosynthetics are vaguely described as confinement, interlocking, and load shedding respectively but not fully understood. The uncertainties of the mechanisms have been reflected as overconservativeness, inconsistence and empiricism in current design methods of those applications. Various researches have been widely carried on to investigate the mechanisms of reinforcement of the above mentioned applications, especially the geosynthetic-soil interactions and then quantitatively consider them into design methods. Numerical modeling characterized as cost- and time- saving, is preferred in many circumstances. An appropriate modeling strategy is vital to yield reliable results. This paper reviewed and summarized the modeling techniques used to model modular-block MSE walls, reinforced embankments/slopes, and reinforced paved/unpaved roads, which include conventional continuum modeling based on constitutive relationships as well as micro-mechanical modeling based on Newton's law of motion, i.e., modeling the soil mass as an assembly of soil particles governed by universal physics principles. The review of conventional continuum modeling includes constitutive models for soils, geosynthetics and other components (e.g., modular blocks), interface models for contacts between dissimilar materials, and simulation of construction, while the review of the micro-mechanical modeling is extended to the principle of the micro-mechanical modeling and how the micro-mechanical modeling is implemented to model the geosynthetic-soil interaction by using the most popular micro-mechanical scheme-PFC as an example. The objective of this paper is to provide a state-of-art review of the various numerical modeling techniques and consequently promote the usage of numerical modeling in research and practice of geosynthetic-reinforced earth structures.
Miller G.A.,University of Oklahoma |
Tan N.K.,Terracon |
Muraleetharan K.K.,University of Oklahoma
Geotechnical Special Publication | Year: 2012
Pre-bored monocell pressuremeter tests were conducted in a calibration chamber containing compacted low plasticity clayey silt. A miniature pressuremeter probe having a diameter of 15.2 mm and expandable length to diameter ratio of 8.5 was used; this provided a soil bed diameter (610 mm) to probe diameter ratio of 40. Pressuremeter tests were conducted under three different levels of net normal stress (103, 152, and 206 kPa) and four different levels of matric suction (nominally 15, 28, 38, and 48 kPa). This paper presents results of the pressuremeter tests with emphasis on the interpretation of elastic modulus and the influence of matric suction. Results indicate that the pressuremeter modulus is sensitive to the initial soil state as defined by the net normal stress, matric suction, and void ratio (or dry unit weight). © 2012 American Society of Civil Engineers.
Zhang Y.,Terracon |
Michalowski R.L.,University of Michigan
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2015
Frost heave and thaw settlement are the cause of substantial damage to infrastructure in regions of seasonal freezing as well as seasonal thawing (permafrost). While frost heaving of soils has been researched for decades, less attention has been paid to quantitative estimates of settlement and loss of strength of soils due to thawing. A constitutive model is developed, capable of simulating freezing and thawing of soils, and associated changes in the soil strength. While the porosity growth parameters describing frost heaving have been calibrated and validated for a specific soil, the description of the thawing phase has not been validated due to a lack of experimental data. The yielding of the frozen soil is described using the critical state concept, with the pore ice content being an important parameter affecting the yield function. The model was calibrated using available laboratory test data and used in the simulation of a freezing-thawing cycle in the soil with embedded footing. © 2015 American Society of Civil Engineers.
Zein A.S.,Terracon |
Gassman S.L.,University of South Carolina
Journal of Bridge Engineering | Year: 2010
Numerical and experimental studies were performed to assess the transient impact response of 11 T-beams with various dimensions and aspect ratios. Numerical modeling was performed using a three stage finite-element modeling procedure which included modal analysis, resonant analysis, and three-dimensional transient dynamic analysis. The response at impact locations on both the top centerline of the flange and the bottom centerline of the web was investigated. Physical models of three of the beams were constructed in the laboratory to determine the physical response of the beams when subjected to a transient impact and to verify the numerical results. Relationships between the fundamental frequencies and the frequencies of higher cross-sectional modes of vibration were established for the various aspect ratios. Shape factors were derived from the numerical and experimental results. The practical significance of the results is demonstrated for a project where impact-echo testing was used to nondestructively assess the condition of a decommissioned concrete T-shaped girder. © 2010 ASCE.
Terracon | Date: 2015-09-28
Methods and systems for optimizing pile design based on pile driver data are provided. A pile driving performance monitoring (PDPM) system captures pile driver data for a pile in an identified location using a pile driver data capture device. The pile driver data comprises a pile penetration depth and pile penetration rate based on percussive hammer. The identified location can be determined using a global positioning system. A parsing program component analyzes the pile driver data for the pile. The parsing program component determines whether the pile driver data of the pile meets an anticipated-pile driving criteria, the anticipated-pile driving criteria comprises a test pile driver data that correlates with a predefined capacity for a pile in the identified location. The pile is added to an acceptance report when it meets the anticipated-pile driving criteria or added to exception report when it does not meet the anticipated-pile driving criteria.
News Article | November 3, 2016
OLATHE, Kan., Nov. 3, 2016 /PRNewswire/ -- Terracon, a leading provider of environmental, facilities, geotechnical, and materials services, announces the establishment of its first Virginia office locations through the acquisition of Geotechnical Consulting & Testing Inc. (GC&T),...
News Article | December 6, 2016
OLATHE, Kan., Dec. 6, 2016 /PRNewswire/ -- Terracon, a leading provider of environmental, facilities, geotechnical, and materials services, announces the acquisition of CHJ Consultants (CHJ). CHJ provides geotechnical and materials testing services from its three southern California...