The Experts below are selected from a list of 5583 Experts worldwide ranked by ideXlab platform
K Y Yong - One of the best experts on this subject based on the ideXlab platform.
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Monitoring of Dynamic Compaction by deceleration measurements
Computers and Geotechnics, 2003Co-Authors: Y K Chow, D M Yong, K Y YongAbstract:Abstract A method of estimating the degree and depth of improvement in the Dynamic Compaction of loose granular soil by matching the computed decelerations of the pounder from a numerical model to the measured decelerations is presented. This method uses a simple one-dimensional wave equation model in which the soil beneath the pounder is represented by an elastic laterally confined soil column while the surrounding soil is represented by a series of springs and dashpots. The spring simulates the Dynamic soil stiffness while the dashpot accounts for the radiation damping effect. Despite the simplifying assumptions in the model, the computed results for the degree and depth of improvement show an encouraging measure of agreement with available data from a laboratory test and field measurements from a Dynamic Compaction site. The proposed method is potentially useful for the monitoring of Dynamic Compaction of loose granular soil. And like any new technique, further verifications of the approach are necessary to develop it into a reliable method.
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Dynamic Compaction of loose granular soils effect of print spacing
Journal of Geotechnical Engineering, 1994Co-Authors: Y K Chow, D M Yong, K Y YongAbstract:A method is presented to evaluate the effect of print spacing on the Dynamic Compaction of loose granular soils. It uses a recently developed wave-equation model together with an approach to predict the lateral extent of soil improvement around the pounder. The procedure to evaluate the effect of print spacing is demonstrated using two examples, which show that the most critical areas are the center of the grid and the middle of the side of the grid where the least improvement of soil is achieved. Three reported case histories of Dynamic-Compaction projects are analyzed, and the solutions are shown to be in good agreement with those obtained from the field. Two design curves, one for the center of the grid and the other for the middle of the side of the grid, are established. These curves summarize the influence of print spacing on the effectiveness of Dynamic Compaction in densifying the soil at these two critical locations and are useful for the selection of print spacing in Dynamic-Compaction projects.
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Dynamic Compaction OF LOOSE SAND DEPOSITS
Soils and Foundations, 1992Co-Authors: Y K Chow, D M Yong, K Y YongAbstract:A theoretical framework based on a one-dimensional wave equation model in conjunction with standard penetration test (SPT) results for the Dynamic Compaction analysis of loose sand deposits is presented. The wave equation model properly simulates the Dynamic interaction between the pounder and the soil, the punch-through failure mechanism as well as the propagation of stress waves in the soil. Two reported case histories are analyzed and it is demonstrated that the pounder penetration, the degree and depth of soil improvement can be reasonably predicted using this model. The computed results of soil improvement are found to agree closer to those estimated based on the correlations of Skempton (1986) and Peck and Bazaraa (1969). The correlation of Gibbs and Holtz (1957) appears to lead to an over-estimation of the relative density of sand after Dynamic Compaction. It is believed that the theoretical framework discussed in this paper can provide a better understanding of the Dynamic Compaction process and may in due course lead to more cost-effective means of designing Dynamic Compaction work.
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Dynamic Compaction analysis
Journal of Geotechnical Engineering, 1992Co-Authors: Y K Chow, D M Yong, K Y YongAbstract:A simplified model based on the one‐dimensional wave equation, which accounts for the interaction of the pounder and the soil, and the propagation of stress wave in the soil during the Dynamic Compaction of loose granular soil is presented. The soil beneath the pounder is represented by a nonlinear soil column, while the surrounding soil is represented by a series of springs and dashpots. The spring simulates the Dynamic soil stiffness and the dashpot accounts for the radiation damping effect. The input soil parameters of the model can be determined in the laboratory or estimated from correlations with measured field data. In spite of the various simplifying assumptions in the model and the predictive method, computed results, such as pounder penetration and degree and depth of improvement, show an encouraging measure of agreement with available field measurements from two Dynamic Compaction projects. The proposed model is potentially useful for the analysis of Dynamic Compaction of loose granular soil.
S. K. A. Au - One of the best experts on this subject based on the ideXlab platform.
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a new laboratory apparatus for studying Dynamic Compaction grouting into granular soils
Soils and Foundations, 2013Co-Authors: Shanyong Wang, Dave Chan, S. K. A. AuAbstract:Abstract As granular soils may be compressible or have inadequate strength, Compaction is particularly useful when soils are subjected to Dynamic loading or cyclic loading. A new laboratory apparatus for investigating Dynamic Compaction has been designed and fabricated. The basic principle of this new technique is to introduce vibrations during the expansion process in static Compaction grouting. In these tests, the injection pressure, the excess pore water pressure, and the change in void ratio of the specimens are measured. The main focus is to investigate the development of the injection pressure, the void ratio, and the excess pore water pressure due to Dynamic Compaction and the subsequent consolidation of the soils. In addition, the relative density of the soils is used to evaluate the Dynamic Compaction efficiency. Scaled laboratory experiments are conducted to study the effect of this Dynamic Compaction frequency on Compaction efficiency. The experimental results show that the change in void ratio in the Dynamic Compaction tests is about four times greater than that in the static Compaction tests. Dynamic Compaction frequency plays an important role in soil densification due to Dynamic Compaction.
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Laboratory study of static and Dynamic Compaction grouting in triaxial condition
Geomechanics and Geoengineering, 2011Co-Authors: Shanyong Wang, Dave Chan, S. K. A. AuAbstract:This research paper is focused on the fundamental behaviour of applying static and Dynamic Compaction grouting techniques on completely decomposed granite (CDG) soils in Hong Kong. Using the modified triaxial apparatus and a novel pulse wave generator, laboratory tests were performed to identify the critical controllable factors of static and Dynamic Compaction grouting techniques in optimizing Compaction effectiveness. The distinguishing feature of this laboratory apparatus is that it can simulate triaxial condition of static and Dynamic Compaction grouting. The effective confining pressure, the lateral pressure coefficient, excess pore water pressure, back pressure and void ratio change of the specimen were measured in this study. At the same time, the Dynamic Compaction grouting pressure, Dynamic Compaction frequency, and Dynamic Compaction duration were controlled. Moreover, the effects of effective confining pressure and injection rate on the Compaction efficiency in static tests were studied. The st...
Y K Chow - One of the best experts on this subject based on the ideXlab platform.
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Monitoring of Dynamic Compaction by deceleration measurements
Computers and Geotechnics, 2003Co-Authors: Y K Chow, D M Yong, K Y YongAbstract:Abstract A method of estimating the degree and depth of improvement in the Dynamic Compaction of loose granular soil by matching the computed decelerations of the pounder from a numerical model to the measured decelerations is presented. This method uses a simple one-dimensional wave equation model in which the soil beneath the pounder is represented by an elastic laterally confined soil column while the surrounding soil is represented by a series of springs and dashpots. The spring simulates the Dynamic soil stiffness while the dashpot accounts for the radiation damping effect. Despite the simplifying assumptions in the model, the computed results for the degree and depth of improvement show an encouraging measure of agreement with available data from a laboratory test and field measurements from a Dynamic Compaction site. The proposed method is potentially useful for the monitoring of Dynamic Compaction of loose granular soil. And like any new technique, further verifications of the approach are necessary to develop it into a reliable method.
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Dynamic Compaction of loose granular soils effect of print spacing
Journal of Geotechnical Engineering, 1994Co-Authors: Y K Chow, D M Yong, K Y YongAbstract:A method is presented to evaluate the effect of print spacing on the Dynamic Compaction of loose granular soils. It uses a recently developed wave-equation model together with an approach to predict the lateral extent of soil improvement around the pounder. The procedure to evaluate the effect of print spacing is demonstrated using two examples, which show that the most critical areas are the center of the grid and the middle of the side of the grid where the least improvement of soil is achieved. Three reported case histories of Dynamic-Compaction projects are analyzed, and the solutions are shown to be in good agreement with those obtained from the field. Two design curves, one for the center of the grid and the other for the middle of the side of the grid, are established. These curves summarize the influence of print spacing on the effectiveness of Dynamic Compaction in densifying the soil at these two critical locations and are useful for the selection of print spacing in Dynamic-Compaction projects.
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Dynamic Compaction OF LOOSE SAND DEPOSITS
Soils and Foundations, 1992Co-Authors: Y K Chow, D M Yong, K Y YongAbstract:A theoretical framework based on a one-dimensional wave equation model in conjunction with standard penetration test (SPT) results for the Dynamic Compaction analysis of loose sand deposits is presented. The wave equation model properly simulates the Dynamic interaction between the pounder and the soil, the punch-through failure mechanism as well as the propagation of stress waves in the soil. Two reported case histories are analyzed and it is demonstrated that the pounder penetration, the degree and depth of soil improvement can be reasonably predicted using this model. The computed results of soil improvement are found to agree closer to those estimated based on the correlations of Skempton (1986) and Peck and Bazaraa (1969). The correlation of Gibbs and Holtz (1957) appears to lead to an over-estimation of the relative density of sand after Dynamic Compaction. It is believed that the theoretical framework discussed in this paper can provide a better understanding of the Dynamic Compaction process and may in due course lead to more cost-effective means of designing Dynamic Compaction work.
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Dynamic Compaction analysis
Journal of Geotechnical Engineering, 1992Co-Authors: Y K Chow, D M Yong, K Y YongAbstract:A simplified model based on the one‐dimensional wave equation, which accounts for the interaction of the pounder and the soil, and the propagation of stress wave in the soil during the Dynamic Compaction of loose granular soil is presented. The soil beneath the pounder is represented by a nonlinear soil column, while the surrounding soil is represented by a series of springs and dashpots. The spring simulates the Dynamic soil stiffness and the dashpot accounts for the radiation damping effect. The input soil parameters of the model can be determined in the laboratory or estimated from correlations with measured field data. In spite of the various simplifying assumptions in the model and the predictive method, computed results, such as pounder penetration and degree and depth of improvement, show an encouraging measure of agreement with available field measurements from two Dynamic Compaction projects. The proposed model is potentially useful for the analysis of Dynamic Compaction of loose granular soil.
Randall M German - One of the best experts on this subject based on the ideXlab platform.
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an overview of Dynamic Compaction in powder metallurgy
International Materials Reviews, 2008Co-Authors: Guneet Sethi, N S Myers, Randall M GermanAbstract:AbstractThis paper is a critical review of Dynamic Compaction as a means to densify metal powders. Dynamic Compaction was discovered in the 1960s. Most of the investigations since then have focused mainly on the physics dealing with energy, motion and force aspects of the process. Owing to this, there is a lack of knowledge of the effects of preprocessing and processing factors on this process. This knowledge gap has created skepticism in the PM community about this process' practice. This review attempts to bridge this gap and highlights the powder metallurgical aspects of Dynamic Compaction by emphasising the key powder related factors and processing parameters affecting Dynamic Compaction. Powder related factors include powder characteristics and the processing parameters including the machine operating parameters. Attention has been given to iron, aluminium and copper powders. Through this review, this article paves the way to design of high density Dynamic Compaction systems based on the final PM com...
John Cogar - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Compaction of porous silica powder
Journal of Applied Physics, 2005Co-Authors: John P Borg, David J Chapman, K Tsembelis, W G Proud, John CogarAbstract:The Dynamic Compaction characteristics of a porous silicon dioxide (SiO2) powder are reported. The initial specific volumes of the samples were either V00=1.30, 4.0, or 10.0cm3∕g whereas the silicon dioxide has a matrix specific volume of V0=0.455cm3∕g. The impact velocity ranges from 0.25to1.0km∕s and the shock incident pressure on the silica ranges from 0.77to2.25GPa. The shock velocity–particle velocity exhibited a linear relationship within this range. Although these tests represent the low end of Dynamic Compaction, the Dynamic tests compare favorably to extrapolated data available in the open literature. Theoretical pressure–particle velocity and shock velocity–particle velocity curves were generated using a P-α Compaction curve. The P-α Compaction curve accurately represented the pressure–particle velocity and shock velocity–particle velocity Hugoniot curves for the low specific volume powder, specifically V00=1.30cm3∕g. However, the P-α Compaction curve did not accurately represent the pressure–pa...
