Copyright (c) 2013 University of Connecticut All rights reserved. http://digitalcommons.uconn.edu/cee_techreports Recent documents in Technical Reports en-us Tue, 09 Apr 2013 17:30:36 PDT 3600 http://digitalcommons.uconn.edu/cee_techreports/4 http://digitalcommons.uconn.edu/cee_techreports/4 Tue, 30 Aug 2011 07:46:40 PDT The report presents a constitutive model for simulating the high strain-rate behavior of sands. Based on the concepts of critical-state soil mechanics, the bounding surface plasticity theory and the overstress theory of viscoplasticity, the constitutive model simulates the high strain-rate behavior of sands under uniaxial, triaxial and multiaxial loading conditions. The model parameters are determined for Ottawa and Fontainebleau sands, and the performance of the model under extreme transient loading conditions is demonstrated through simulations of split Hopkinson pressure bar tests up to a strain rate of 2000/sec. The constitutive model is implemented in a finite element analysis software to analyze underground tunnels in sand subjected to internal blast loads. Parametric studies are conducted to examine the effect of relative density and type of sand and of the depth of tunnel on the variation of stresses and deformations in the soil adjacent to the tunnels.

]]> William Higgins et al. http://digitalcommons.uconn.edu/cee_techreports/3 http://digitalcommons.uconn.edu/cee_techreports/3 Tue, 02 Aug 2011 10:34:47 PDT This report presents a strain-rate dependent plastic constitutive model for clays. Based on the concepts of critical-state soil mechanics and bounding surface plasticity theory, the model reproduces the mechanical response of clays under multi-axial loading conditions and predicts both the drained and undrained behavior. The model parameters are determined for Boston Blue Clay, London Clay and Kaolin Clay, and the performance of the model in simulating the mechanical response of these clays is demonstrated for low to medium strain rates. The sensitivity of each model parameter is checked by perturbing the calibrated values by ±20%. Subsequently, a probabilistic analysis using Monte Carlo simulations is performed by treating the model parameters as random variables and the impact of the statistics of the parameters on the undrained shear strength is investigated.

]]> Harry Martindale et al. http://digitalcommons.uconn.edu/cee_techreports/2 http://digitalcommons.uconn.edu/cee_techreports/2 Thu, 28 Jul 2011 11:17:31 PDT Laterally loaded piles are analyzed using the Fourier finite element method. Pile response was observed to be a function of the relative stiffness of pile and soil and of the pile slenderness ratio. The analysis is mostly performed for piles embedded in elastic soil with constant and linearly varying modulus although the pile response in two-layer soil profiles is also investigated. Equations describing pile head deflection, rotation and maximum bending moment are proposed for flexible long piles and stubby rigid piles. The design equations were developed after plotting the pile responses as functions of pile-soil stiffness ratio and pile slenderness ratio. These plots can also be used as design charts. Design examples illustrating the use of the analysis are also provided.

]]> William Higgins et al. http://digitalcommons.uconn.edu/cee_techreports/1 http://digitalcommons.uconn.edu/cee_techreports/1 Thu, 28 Jul 2011 10:40:56 PDT The built environment serves as a dynamic interface through which the human society and the ecosystem interact and influence each other. Understanding this interdependence is key to understanding sustainability as it applies to civil engineering. There is a growing consensus that delivering a sustainable built environment starts with incorporating sustainability thoughts at the planning and design stages of a project. Geotechnical engineering is the most resource intensive of all the civil engineering disciplines and can significantly influence the sustainability of infrastructure development because of its early position in the construction process. In this report, a review is made of the scope geotechnical engineering offers towards sustainable development of civil infrastructure. The philosophies and definitions of sustainability as applicable in geotechnical engineering are discussed and a comprehensive review is done of the research studies performed in geotechnical engineering that contributes to sustainable development. It is revealed from the literature review that there is a need for a quantitative sustainability assessment framework in geotechnical engineering. Consequently, a multicriteria based sustainability assessment framework is introduced that can be used at the planning and design stages of geotechnical projects. This quantitative framework combines life cycle assessment, environmental impact assessment and cost benefit analysis, and can be used to assess the relative sustainability of different design choices in geotechnical engineering.

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