The Experts below are selected from a list of 12627 Experts worldwide ranked by ideXlab platform
Donatella Sterpi - One of the best experts on this subject based on the ideXlab platform.
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effect of freeze thaw cycles on the hydraulic conductivity of a compacted clayey silt and influence of the Compaction Energy
Soils and Foundations, 2015Co-Authors: Donatella SterpiAbstract:Abstract Compacted clay layers are often used in impervious barrier systems to prevent the migration of water and pollutants. Environmental factors, acting during or after the clay deposition, may affect the layer integrity and induce a variation of hydraulic conductivity over time. The aim of the present research is to assess this variation when induced by freeze–thaw cycles. The paper summarizes some results of tests performed on a series of clayey silt samples, reconstituted at various levels of Compaction Energy and subjected to cyclic freezing according to a controlled and repeatable procedure, set to reproduce the natural environmental conditions. The hydraulic conductivity is evaluated directly from a flexible wall permeameter and indirectly from oedometric tests. The results show the consequences of cyclic freezing in relation to the Compaction level and lead to insights into the development of fracture networks responsible for the increase in hydraulic conductivity.
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Effect of freeze–thaw cycles on the hydraulic conductivity of a compacted clayey silt and influence of the Compaction Energy
Soils and Foundations, 2015Co-Authors: Donatella SterpiAbstract:Abstract Compacted clay layers are often used in impervious barrier systems to prevent the migration of water and pollutants. Environmental factors, acting during or after the clay deposition, may affect the layer integrity and induce a variation of hydraulic conductivity over time. The aim of the present research is to assess this variation when induced by freeze–thaw cycles. The paper summarizes some results of tests performed on a series of clayey silt samples, reconstituted at various levels of Compaction Energy and subjected to cyclic freezing according to a controlled and repeatable procedure, set to reproduce the natural environmental conditions. The hydraulic conductivity is evaluated directly from a flexible wall permeameter and indirectly from oedometric tests. The results show the consequences of cyclic freezing in relation to the Compaction level and lead to insights into the development of fracture networks responsible for the increase in hydraulic conductivity.
Junichi Koseki - One of the best experts on this subject based on the ideXlab platform.
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large scale triaxial tests to study effects of Compaction Energy and large cyclic loading history on shear behavior of gravel
Soils and Foundations, 2010Co-Authors: Sajjad Maqbool, Junichi KosekiAbstract:This study examines the effects of Compaction on peak strength and small strain stiffness of large prismatic specimens of gravel by conducting monotonic and large cyclic loading triaxial compression tests. The specimens were prepared using an automatic Compaction system while measuring quantitatively the Compaction Energy. For the evaluation of small strain stiffness, a static technique using small cyclic vertical loading with local strain measurement and a dynamic technique using P-wave measurement were employed. It was revealed that the peak strength of compacted gravel increased in a non-linear manner with the increase in the Compaction Energy. On the other hand, the difference between statically and dynamically measured small strain Young's moduli was reduced as a result of increase in the Compaction Energy. The peak strengths of three almost equally dense specimens were found similar to each other irrespective of the difference in the loading histories with/without large cyclic loading. However, the values of the axial strain at the peak stress state were different among the three specimens, affected by the different loading histories.
Muhammad Waseem - One of the best experts on this subject based on the ideXlab platform.
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Compaction performance analysis of alum sludge waste modified soil
Construction and Building Materials, 2020Co-Authors: Syyed Adnan Raheel Shah, Zarnish Mahmood, Aqsa Nisar, Muhammad Aamir, Amjad Farid, Muhammad WaseemAbstract:Abstract Sustainable construction is one of the ultimate requirements of the engineering field. Addition of waste materials not only contribute to the improvement of the density of soils but also help in the enhancement of its strength properties. In the field, Compaction is achieved by compactors and rollers, which consumes a lot of Energy for this purpose. In this study, two methods related to Compaction Energy have been applied to study the relation of Compaction Energy with the strength of soil before and after addition of alum sludge as a soil stabilizer. An advanced Artificial Neural Networks (ANNs) technique has been applied with reference to the addition of alum sludge percentage, plasticity index, specific gravity, optimum moisture content, maximum dry density, AASHTO classification, USCS classification, and group index. It was found that soil strength can be improved even at a low Compaction Energy level of 600KN-m/m3 by the addition of optimum percentage of 8% alum sludge as a soil stabilizer. So, roller Compaction effort can also be reduced by addition of this soil stabilizer to save Compaction cost i.e. saving of roller fuel consumption and rental cost as well. This study will not only help in environment-friendly construction but will also manage finance by utilization of optimum Compaction Energy in the mega projects.
John S. Schwartz - One of the best experts on this subject based on the ideXlab platform.
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The Low Compaction Grading Technique on Steep Reclaimed Slopes: Soil Characterization and Static Slope Stability
Geotechnical and Geological Engineering, 2013Co-Authors: Isaac A. Jeldes, Eric C. Drumm, John S. SchwartzAbstract:Since the Surface Mining and Control Reclamation Act of 1977, US coal mining companies have been required by law to restore the approximate ground contours that existed prior to mining. To ensure mass stability and limit erosion, the reclaimed materials have traditionally been placed with significant Compaction Energy. The Forest Reclamation Approach (FRA) is a relatively new approach that has been successfully used to facilitate the fast establishment of native healthy forests. The FRA method specifies the use of low Compaction Energy in the top 1.2–1.5 m of the contour, which may be in conflict with general considerations for mechanical slope stability. Although successful for reforestation, the stability of FRA slopes has not been fully investigated and a rational stability method has not been identified. Further, a mechanics-based analysis is limited due to the significant amount of oversize particles which makes the sampling and measurement of soil strength properties difficult. To investigate the stability of steep FRA slopes (steeper than 20°), three reclaimed coal mining sites in the Appalachian region of East Tennessee were investigated. The stability was evaluated by several methods to identify the predominant failure modes. The infinite slope method, coupled with the estimation of the shear strength from field observations, was shown to provide a rational means to evaluate the stability of FRA slopes. The analysis results suggest that the low Compaction of the surface materials may not compromise the long-term stability for the sites and material properties investigated.
Sajjad Maqbool - One of the best experts on this subject based on the ideXlab platform.
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large scale triaxial tests to study effects of Compaction Energy and large cyclic loading history on shear behavior of gravel
Soils and Foundations, 2010Co-Authors: Sajjad Maqbool, Junichi KosekiAbstract:This study examines the effects of Compaction on peak strength and small strain stiffness of large prismatic specimens of gravel by conducting monotonic and large cyclic loading triaxial compression tests. The specimens were prepared using an automatic Compaction system while measuring quantitatively the Compaction Energy. For the evaluation of small strain stiffness, a static technique using small cyclic vertical loading with local strain measurement and a dynamic technique using P-wave measurement were employed. It was revealed that the peak strength of compacted gravel increased in a non-linear manner with the increase in the Compaction Energy. On the other hand, the difference between statically and dynamically measured small strain Young's moduli was reduced as a result of increase in the Compaction Energy. The peak strengths of three almost equally dense specimens were found similar to each other irrespective of the difference in the loading histories with/without large cyclic loading. However, the values of the axial strain at the peak stress state were different among the three specimens, affected by the different loading histories.