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Rosen J.B.,Geosyntec Consultants | Arnold M.A.,Institute of Geotechnical Engineering | Bachus R.C.,Geosyntec Consultants | Schauer D.,Geosyntec Consultants | Berrios A.,BAUER Foundation Corporation
Geotechnical Special Publication | Year: 2011

Large scale geotechnical earthworks projects, specifically those related to earth dams, dikes, and levees, often require construction of deep vertical seepage barriers. The demands on these projects of contract compliance, resource scheduling, quality control, and budget management require structured and efficient management of the large associated data sets. Ineffective data management can contribute to the complexity, duration and budget of the project. This paper discusses an application of Geographic Information Systems (GIS) technology to capture information from multiple data streams and provide geotechnical feedback, quality control, and project control feedback. This technology was used to provide information to the U.S. Army Corps of Engineers (USACE) as part of the high-profile rehabilitation of the 232-kilometer long Herbert Hoover Dike (HHD) around Lake Okeechobee in South Florida. The implication of this technology to other earthwork projects is demonstrated. © 2011 ASCE.

Cui C.-Y.,Dalian University of Technology | Cui C.-Y.,Dalian Maritime University | Luan M.-T.,Institute of Geotechnical Engineering | Li M.-G.,Dalian University of Technology
Geotechnical Special Publication | Year: 2010

On the soft grounds, effects of consolidation on performance of the system of piled rafts as well as superstructures cannot be overlooked due to nonlinear interaction characteristics. Conventional methods of engineering design and numerical procedures of two-dimensional interaction analysis cannot realistically simulate loading and deformation mechanism of the interaction system and cannot completely predict variations of deformations and internal forces of both structure and piled raft foundation. Therefore in order to well understand long-term behavior of the interaction system, time-dependent effect of soil deformations on performance of the interaction system of piled rafts and foundations as well as superstructure is evaluated in this paper. The nonlinear deformation and strength behavior of foundation soils are taken into account by using the elasto-plastic constitutive model based on Mohr-Coulomb's yield criterion while the consolidation effect of subsoil under loading is incorporated by numerically solving the coupling Biot's equations of consolidation. Numerical analyses are conducted for the structure-raft- foundation interaction system by using the finite element methods. Based on numerical analyses for a given interaction system, both the features of variation in time of internal forces, settlements and the characteristics of compatibility mechanism of interaction system are examined. It is shown that both nonlinear behavior of soft soils and consolidation characteristics of foundation remarkably affect the time-dependent performance of the interaction system. Such dependency is intimately related to variation of excess pore water pressure of subsoil. © 2010 ASCE.

Chen L.,Soochow University of China | Chen L.,Institute of Geotechnical Engineering | Du Y.-J.,Nanjing Southeast University | Liu S.-Y.,Nanjing Southeast University | Jin F.,University of Cambridge
Journal of Hazardous, Toxic, and Radioactive Waste | Year: 2011

In this study, electrical resistivity was related to the fundamental geotechnical properties of cement solidified/stabilized heavy metal-contaminated soils. Lead-contaminated soils were artificially prepared with various concentrations and treated by portland cement Type I at three content levels. The compacted cylindrical specimen was prepared with a diameter of 50 mm and height of 100 mm. The apparent electrical resistivity, electrical conductivity of pore fluid, unconfined compressive strength, and water contents were measured at different curing times. The result shows that the apparent electrical resistivity increases with the increase of curing time and the decrease of porosity and saturation degree as a result of cement hydration development. The effects of lead concentration, cement content, and curing time on the apparent electrical resistivity were discussed. The cementation index m was used to evaluate the cementation degree of cement-treated lead-contaminated soils. Lead pollutant at high concentrations could suppress or retard the hydration of solidified/stabilized soils. Electrical resistivity measurements can be used as a nondestructive method to evaluate the hydration development of solidified/stabilized lead-contaminated soils. © 2011 American Society of Civil Engineers.

Tensay B.G.,Institute of Geotechnical Engineering | Wu W.,Institute of Geotechnical Engineering
Numerical Methods in Geotechnical Engineering - Proceedings of the 7th European Conference on Numerical Methods in Geotechnical Engineering | Year: 2010

The seismic performance of earth dams is usually studied by two dimensional space. However, considerable effort is required to estimate the overall three dimensional dynamic response of dams in a narrow canyon from plane strain analyses of the dam. This is so because the plane strain analysis normally ignores the arching effect of the valley. Researches reported in this paper represent 3D numerical study of an earthfill dam founded on a liquefiable foundation subjected to earthquake loading and effect of canyon geometry on its seismic performance. The shape of the canyon is varied to determine the related effects to the earth dam. A finite difference numerical scheme is used for the study. The assumed 3D model contains all details of the dam body and foundation materials of Tendaho earthfill dam in Ethiopia. Results and discussions related with the significance of these two factors for the seismic performance evaluation of earth dams are presented. © 2010 Taylor & Francis Group, London.

Xue F.C.,Tsinghua University | Xue F.C.,Institute of Geotechnical Engineering | Zhang J.M.,Tsinghua University | Zhang J.M.,Institute of Geotechnical Engineering
Recent Advances in Environmental Vibration - Proceedings of 6th International Symposium on Environmental Vibration, ISEV 2013 | Year: 2013

High-speed railway has gained rapid development in China. Running speeds on the established lines are no less than 200 km/h at the beginning stage and up to 300 km/h for many main high-speed railways. The running speed is likely to be increased in the future. Compared to low and middle speed railways, dynamic effects induced by high-speed train are obviously different, especially in regions with poor quality soils. To investigate the vibration effect of foundation due to highspeed moving loads, a subroutine complied with Fortran language? is added on the platform of the computer software ABAQUS to simulate one or more different types of moving load(s). To eliminate wave reflection at computational boundary and to remove the limitation of traditional viscoelastie boundary that is valid for dynamic; calculation but invalid for static calculation, a special boundary is added to ABAQUS based on the theory of three dimensional static-dynamic unified viscoelastie artificial boundary and its correctness and validity are verified. Considering nonlinearity of material, the vibration effects of foundation are studied for the two cases; ( i) when the speed of a moving load is larger than the shear wave velocity but less than the compression wave velocity; and (ii) when the speed of a moving load is larger than the compression wave velocity of foundation soil. And, vibration displacement, vibration velocity, vibration acceleration and dynamic stresses are obtained. Results indicate that the stress state of soil elements keep (-hanging all the time during the process of load moving and three stress axes correspondingly rotate continuously. For comparison, rotations of axis in vertical plant due to one load with moving speed less than the shear wave velocity of foundation soil art presented.

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