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Articles 10531 - 10560 of 13031

Full-Text Articles in Engineering

Subsequent Consolidation Of Clay Subjected To Undrained Cyclic Loading, Tej B. S. Pradhan, G. Imai, Y. Ueno, T. K. Dam Apr 1995

Subsequent Consolidation Of Clay Subjected To Undrained Cyclic Loading, Tej B. S. Pradhan, G. Imai, Y. Ueno, T. K. Dam

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper is mainly focused on two parts: (a) to clarify the mechanism of migration of excess pore water pressure in clay specimen and (b) subsequent consolidation behavior after the dissipation of excess pore water pressure accumulated due to undrained cyclic loading. A new technique to measure the pore pressure at the mid-height periphery of a triaxial specimen was developed. The effect of loading frequency and the stress level on the generation of excess pore pressure at the top, bottom and at mid-height of the specimen has been discussed. The variation of recompression index due to the dissipation of excess …

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Random Displacement Modulus And Damping Determination, R. C. Chaney Apr 1995

Random Displacement Modulus And Damping Determination, R. C. Chaney

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Modulus and damping values were determined for both undisturbed and remolded silty sand specimens by cyclic triaxial methods utilizing both sinusoidal and random displacement stroke control. Remolded specimens were prepared at 3 different dry unit weights using a preparation technique that gave the same formation factor as the undisturbed specimen. Results indicated that the random displacement method tends to produce results which are similar to those obtained by the sinusoidal procedure at shearing strain levels less than 10-1 %. At shearing strain levels greater than 10-1 % the random displacement method gives lower modulus and higher damping ratio …

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A New Method For Determining The Anisotropic Parameters Of Materials Under True Triaxial Cyclic Loading, Q. J. Yang, B. Shackel Apr 1995

A New Method For Determining The Anisotropic Parameters Of Materials Under True Triaxial Cyclic Loading, Q. J. Yang, B. Shackel

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

In this paper a new approach to solving the basic equations of elastic cross-anisotropic stress and strain relationships is presented. The uniqueness of the equations is demonstrated and the conditions for their use are easily controlled in the true triaxial test equipment available in the laboratory. By this approximate solution the four anisotropic parameters of cross-anisotropic materials can be obtained. In addition, so-called fuzzy logic weighting factors are introduced to assess the differences among the observed principal deformations of samples tested. A computer program ANISOLV has been written to calculate the formulated parameters. Some typical examples are given to demonstrate …

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Preshearing Effect On Effective Stress Paths, Q. J. Yang Apr 1995

Preshearing Effect On Effective Stress Paths, Q. J. Yang

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper presents a brief summary of the triaxial single and multi-level loading test technique to model the soils experiencing wind and/or wave kinds of load. Some important findings regarding the shear strength and pore pressure phenomenon in the repeated triaxial experiments are given. The method describing the stress path under single- and multi-level repeated stresses is established in detail. Based on a large number of the test results, some typical stress paths are presented m the effective deviation and normal stress space. The stress paths under single repeated stress at different effective ambient pressures have the same pattern and …

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Changes Of Yield Stress Of Sand During Undrained Cyclic Loading, Y. Tanaka, K. Shirakawa Apr 1995

Changes Of Yield Stress Of Sand During Undrained Cyclic Loading, Y. Tanaka, K. Shirakawa

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

In this study, the yield locus of sand being subjected to several cycles of undrained loading was investigated by using the triaxial testing device capable of measuring the acoustic emission, AE, of soil. The AE measurement indicates that the undrained shear on isotropically consolidated sand changes the shape of yield locus so as to have more kinematic hardening type of yield locus. More importantly, a change occurred in the size of yield locus, and the undrained loading has reduced the size of yield locus. Subsequent undrained cyclic loadings further reduced the size of yield locus so that there were some …

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Maximum Moduli Of Sands Under Various Loadings, X. J. Zhang, M. S. Aggour Apr 1995

Maximum Moduli Of Sands Under Various Loadings, X. J. Zhang, M. S. Aggour

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Maximum moduli are the primary parameter in the determination of wave velocities in soils. They can be evaluated from either laboratory or field testing. In general, the excitation loadings used in laboratory and field testing are different. The resonant column apparatus was used to study the effect of loading type on the maximum moduli of sands. Sinusoidal, random and impulse loading were used. Sand specimens were tested either longitudinally or torsionally with one of the three types of loading at low strain levels, and the low-amplitude moduli were measured. Maximum moduli of the specimens were obtained from the low-amplitude moduli. …

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Settlements Of Breakwater On Soft Seabed Ground Under Ocean Waves, J. Zhou, K. Yasuhara Apr 1995

Settlements Of Breakwater On Soft Seabed Ground Under Ocean Waves, J. Zhou, K. Yasuhara

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A procedure for predicting the wave induced excess pore water pressure and residual strain of clay using the results of cyclic triaxial tests on the reconstituted Ariake clay is described. Thereafter, the results of a numerical analysis by a 2-D dynamic effective stress FEM for a breakwater on a soft clay are presented.

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Earth Pressure Variations Under Cyclic Surcharges, S. M. Mir Mohammad Hosseini Apr 1995

Earth Pressure Variations Under Cyclic Surcharges, S. M. Mir Mohammad Hosseini

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

There are a tremendous studies in literature about the earth pressure, most of them are concentrated on the static loading conditions. The problems of earth pressure under dynamic loadings are still the case of studies. In this paper the results of an experimental studies about variations of earth pressure at rest under different vertical cyclic loadings are presented. Cubical soil samples of 15 cm dimensions were subjected to vertical cyclic stresses and induced lateral pressure behind the rigid side walls of the soil were measured accurately. A dry and uniform sand was used and the samples were prepared by the …

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Soil Property Determination For A Seismic Study, Kenneth M. Berry, Thomas L. Cooling, Stephen L. Mccaskie Apr 1995

Soil Property Determination For A Seismic Study, Kenneth M. Berry, Thomas L. Cooling, Stephen L. Mccaskie

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Static and dynamic soil property data were needed for input into the seismic retrofit design for the I-155 Mississippi River crossing located near the center of the New Madrid Seismic Zone. Soils consisted of recent river alluvium underlain by very dense soils of the Mississippi embayment. The field investigation consisted of conventional borings, downhole geophysical tests to measure shear wave velocity, and seismic piezo-cone soundings. SPT energy measurements were made at one boring to confirm hammer energy for liquefaction evaluation. This paper summarizes the data and provides site specific correlation of shear wave velocity vs. N-value from the seismic cone …

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Modeling Of Volumetric Response Of Cemented Sand Under Cyclic Loading, Krishna R. Reddy Apr 1995

Modeling Of Volumetric Response Of Cemented Sand Under Cyclic Loading, Krishna R. Reddy

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper first describes cyclic tests which were conducted by Iwabuchi (1986) on both uncemented and cemented sands using a true triaxial apparatus. The paper then presents a thermodynamic or endochronic model which was used to predict the volumetric behavior of uncemented and cemented sands under cyclic loading conditions. The predicted results using the thermodynamic model and the test results using the true triaxial apparatus were found to be in good agreement.

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Discussions And Replies — Session I, Multiple Authors Apr 1995

Discussions And Replies — Session I, Multiple Authors

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

No abstract provided.

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Efficiency Of An Energy-Dissipating Barrier, M. P. Luong Apr 1995

Efficiency Of An Energy-Dissipating Barrier, M. P. Luong

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The proposed paper describes some experimental procedures, used in (a) laboratory to recognize the energy-dissipating ability of soil and (b) in centrifuge to generate in-flight stress waves propagating through a centrifugal soil mass in order to investigate the efficiency of a stress wave mitigation barrier. The screening principle of this new type of energy-dissipating barrier has been suggested by the dissipative behavior of sandy soils, evidenced by infrared vibrothermography.

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The Uplift Capacity Of Anchors Embedded In Loose Sand, Adam F. Bolt, Eugeniusz Dembicki Apr 1995

The Uplift Capacity Of Anchors Embedded In Loose Sand, Adam F. Bolt, Eugeniusz Dembicki

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The results of scale model tests of uplift capacity of shallow and deep anchors in loose fully saturated sands are presented. The anchors were subjected to static, cyclic and post cyclic loading. The parameters tested included the effects of embedment ratio, anchor shape, relative soil density, amplitude and number of cycles, and post cyclic response to loading. The factors influencing the behavior of the anchors are discussed.

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Critical Acceleration Levels For Free Standing Bridge Abutments, K. L. Fishman, R. Richards Jr., R. C. Divito Apr 1995

Critical Acceleration Levels For Free Standing Bridge Abutments, K. L. Fishman, R. Richards Jr., R. C. Divito

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

An analytic procedure for predicting threshold accelerations for movement of gravity wall bridge abutments due to earthquake loading is described. The method draws on previous work related to the sliding mode of failure, and a newly developed theory on seismic reduction of bearing capacity. The main contribution of this paper is to present laboratory observations verifying mode of failure and critical acceleration levels predicted by this procedure for model retaining wall bridge abutments subjected to seismic excitation on a shaking table. Three different test series were performed with different interface conditions between the wall, and the bridge deck, soil foundation, …

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Behaviour Of Saturated Sand Models Under Principal Stress Axes Rotation In Shake Table Tests, Eiji Yanagisawa, Fardin Jafarzadeh Apr 1995

Behaviour Of Saturated Sand Models Under Principal Stress Axes Rotation In Shake Table Tests, Eiji Yanagisawa, Fardin Jafarzadeh

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

One dimensional shake table tests were performed on saturated loose or medium dense Toyoura sand models, in order to study the response of level grounds during earthquakes and the nature of generated excess pore water pressure. 12 virgin models which prepared under identical condition, were subjected to cyclic and three different irregular shear stress patterns. It is shown that there is correlation between excess pore pressure ratio and developed shear strain, independent from applied shear stress histories and density of the models. Also, the relations of accumulated shear work as well as normalized shear work, per unit volume, are considered …

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Numerical Modelling Of Shear Wave Propagation In Centrifuge Models, S. P. Gopal Madabhushi Apr 1995

Numerical Modelling Of Shear Wave Propagation In Centrifuge Models, S. P. Gopal Madabhushi

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Shear modulus of a soil layer increases with the effective confining stress. This results in a reduction in the propagation velocity of shear waves as they travel from the bed rock towards the soil surface. In a centrifuge model prototype stresses and strains are recreated at homologous points. Thus the effective confining stress and hence the shear modulus will vary with depth in a centrifuge model. This results in a change in the propagation velocity of the shear waves as they travel from the base of the container towards the soil surface. This change in the propagation velocity was investigated …

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Permanent Displacements And Tilting Angle Of Small Footings On Sand, H. V. P. Truong, P. J. Moore Apr 1995

Permanent Displacements And Tilting Angle Of Small Footings On Sand, H. V. P. Truong, P. J. Moore

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper presents the comparison between the proposed theoretical prediction and experimental results of horizontal and vertical permanent displacements, and tilting angle of small rigid square and rectangular footings on relatively uniform sand. Old and new lumped parameters for different modes of vibrations, i.e. horizontal, vertical and rocking vibrations are used in the analysis. Some good agreement is found between the theory with the new lumped parameters and experiments, but the relevant dynamic soil properties are still the most critical parameters that need to be measured. Finally, effects of frequency and rocking heights are also investigated.

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Factors Affecting Vibration Induced Settlement, D. S. Kim, S. Drabkin Apr 1995

Factors Affecting Vibration Induced Settlement, D. S. Kim, S. Drabkin

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

In urbanized areas, vibration induced settlement on granular soils depends on vibration characteristics including vibration path and source, in-situ stress conditions, and soil properties. Quantitative laboratory assessment of settlement was extrapolated using parametric study of in-situ settlement of sands. It is shown that vibration amplitude should be monitored within the vulnerable soil layers or evaluated considering attenuation characteristics of soil. Combining the effects of influencing factors, the discussed model can be utilized to predict vibration induced settlement of structures on sand.

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KOd Apparatus, Type Tk-1, Longgen Zhu, Lizhi Xu, Jian Du Apr 1995

KOd Apparatus, Type Tk-1, Longgen Zhu, Lizhi Xu, Jian Du

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

The lateral pressure coefficient Kod of soil under the cyclic load is an important parameter in designing structures against wave, earthquake, and wind. The Lateral Pressure Coefficient Apparatus, Type TK-1 under the cyclic load, written in the simplified form of Kod Apparatus, Type TK-1, is especially developed to study and determine Kod. Its structure, specifications and test results have shown that this apparatus has superior performances, met the requirements to study and determine Kod.

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Dynamic Loading Induced Settlement Of Strip Foundation On Geogrid-Reinforced Clay, Braja M. Das, Eun C. Shin, Bang-Woong Shin, Bong-Jik Lee, Ki-Taek Jung Apr 1995

Dynamic Loading Induced Settlement Of Strip Foundation On Geogrid-Reinforced Clay, Braja M. Das, Eun C. Shin, Bang-Woong Shin, Bong-Jik Lee, Ki-Taek Jung

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Laboratory model tests to determine the load. The variation of the maximum permanent supported by geogrid-reinforced saturated clay and subjected to a low-frequency cyclic load are presented. In conducting the test, the foundation was initially subjected to an allowable static load. The cyclic load was then super-imposed over the static permanent settlement of a surface strip foundation settlement with the intensity of the static load and the intensity of the amplitude of the cyclic load are also presented.

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North Morecambe Terminal, Barrow, Ground Stabilisation And Pile Foundations, C. A. Raison, B. C. Slocombe, A. L. Bell, J. I. Baez Apr 1995

North Morecambe Terminal, Barrow, Ground Stabilisation And Pile Foundations, C. A. Raison, B. C. Slocombe, A. L. Bell, J. I. Baez

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Very poor ground conditions and soils that were susceptible to liquefaction to depths of up to 20m beneath the site were major problems for the construction of the largest natural gas processing terminal in Europe. An innovative foundation solution combining deep vibro compaction with short cast in place piles driven into the treated soils was adopted as both cost and programme effective. The Design and Build project also included advance civils work comprising earthworks, drainage and road construction. The contract started in September 1991 and was completed by October 1992, with the process plant programmed to be on-stream by October …

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A Simple Model For Pore Pressure Build-Up Of Soil Under Dynamic Loadings, J. H. Hwang, C. H. Chen Apr 1995

A Simple Model For Pore Pressure Build-Up Of Soil Under Dynamic Loadings, J. H. Hwang, C. H. Chen

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A simple pore pressure build-up model is introduced in this paper to simulate the effective-stress paths of saturated soils subjected to dynamic loadings. It is a five-parameter model in which two pairs of two parameters are used to define the effective-stress paths during the loading phases of first cycle and post-phase-transformations, respectively, and a dynamic pore pressure parameter is judiciously introduced to represent the increment of pore pressure due to shear loading in between the previous two phases. All parameters can be easily deduced from conventional undrained triaxial tests. Satisfactory results have been achieved for case studies including published results …

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Liquefaction During The 1991 April 22 Telire-Limon Earthquake And Correlations With The Methods Of Seed And Iwasaki, Per Hafström, Jan Skogsberg, Anders Bodare Apr 1995

Liquefaction During The 1991 April 22 Telire-Limon Earthquake And Correlations With The Methods Of Seed And Iwasaki, Per Hafström, Jan Skogsberg, Anders Bodare

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Sites within the area affected by liquefaction due to the 22 April 1991 Limón-Telire earthquake, have been investigated in order to compare the results of some empirical methods with the incidents observed during the earthquake. The purpose of this comparison was to suggest a suitable method to be used when assessing the risk for liquefaction in Costa Rica in the future.

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Liquefaction-Induced Settlements In Sand Deposits, Yasuhiro Shamoto, Masayoshi Sato, Jian-Min Zhang Apr 1995

Liquefaction-Induced Settlements In Sand Deposits, Yasuhiro Shamoto, Masayoshi Sato, Jian-Min Zhang

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

This paper presents a simplified method for estimating the liquefaction-induced settlements of saturated sand deposits. Based on several kinds of undrained cyclic loading tests followed by drained reconsolidation under the different boundary constraint conditions of non-zero and zero lateral strains for different sands, it has been found that there exists a good correlation between the rates of change in 'surplus void ratio' of sand (difference between initial void ratio and minimum void ratio) after both complete and incomplete liquefaction, and the maximum shear strain induced during cyclic loading. The predicted results have been compared favorably with experimental observations of shake …

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A Procedure To Assess The Stability Of Buried Structures Against Liquefaction-Induced Ground Deformations, M. Satoh, M. Hamada, R. Isoyama, A. Hatakeyama Apr 1995

A Procedure To Assess The Stability Of Buried Structures Against Liquefaction-Induced Ground Deformations, M. Satoh, M. Hamada, R. Isoyama, A. Hatakeyama

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

First, an empirical formula to predict the magnitude of permanent ground displacement is proposed based on the observed data at the past earthquake events. Next, a simplified procedure to estimate the failure probability of buried pipes is proposed, in which the model of non-linear beam supported by ground spring elements is used to calculate the strain in the pipe by following the response displacement method. Finally, a simplified method to obtain the probability considering failure modes expected to occur in the pipe is proposed and some numerical example showing the probability and discussions follow.

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Liquefaction Case Study Of Volcanic Gravel Layer During 1993 Hokkaido-Nansei-Oki Earthquake, T. Kokusho, Y. Tanaka, K. Kudo, T. Kawai Apr 1995

Liquefaction Case Study Of Volcanic Gravel Layer During 1993 Hokkaido-Nansei-Oki Earthquake, T. Kokusho, Y. Tanaka, K. Kudo, T. Kawai

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

During the Hokkaido-Nansei-Oki Earthquake, a high-land area around the foot of the volcano, Mt. Komagatake, in Hokkaido in Northern Japan experienced liquefaction phenomena inflicting damages of differential settlement in some tens of houses in the area. Several kinds of geotechnical site investigations were carried out to study the cause of the damage in a typical liquefaction site. Trenching and geological survey disclosed that Holocene debris avalanche deposit containing a plenty of large rocks actually liquefied. The undrained cyclic triaxial test was carried out on large intact samples taken out by the in-situ freezing sampling. The stress ratio measured in the …

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Shaking Table Tests On Transient Flow Of Liquefied Ground, I. Towhata, H. Toyota Apr 1995

Shaking Table Tests On Transient Flow Of Liquefied Ground, I. Towhata, H. Toyota

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

An attempt was made to predict the time history of the lateral displacement of ground that liquefied due to earthquakes. The study was initiated by model tests to examine the nature of liquefied sand. The knowledge thus obtained was combined with the theory of Lagrangean equation of motion in order to develop a method of prediction. Comparison was then made between prediction and observation.

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The Liquefaction Of Sand Lenses Due To Cyclic Loading, J. D. Holchin, L. E. Vallejo Apr 1995

The Liquefaction Of Sand Lenses Due To Cyclic Loading, J. D. Holchin, L. E. Vallejo

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Many studies have been conducted on the effects of cyclic loading on homogeneous saturated deposits of sand, and to a lesser extent on silt and clay. In contrast, very little research has been performed on the effects of cyclic loading on saturated sand lenses located within clay masses. Sand lenses and thin discontinuous layers of loose sand are frequently encountered in saturated clay or silt deposits located in areas of the United States prone to earthquakes. Sand lenses are also frequently associated with hydraulic fill structures, which are known to perform poorly during earthquake loading. The liquefaction and failure of …

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Predicting Seismic Liquefaction Using Neural Networks, A. T. C. Goh Apr 1995

Predicting Seismic Liquefaction Using Neural Networks, A. T. C. Goh

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Neural networks have emerged as a powerful computational technique for modeling nonlinear multivariate relationships. The neural network is a product of artificial intelligence research. This paper examines the feasibility of using neural networks for assessing liquefaction potential, from actual field records. The paper starts with a brief overview of the basic architecture and concepts of neural networks. The application of the neural network methodology to evaluate seismic liquefaction potential is then presented.

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Generalized Plasticity And Cyclic Pressuremeter Test Modelling, A. Saïtta, J. Canou, L. Dormieux Apr 1995

Generalized Plasticity And Cyclic Pressuremeter Test Modelling, A. Saïtta, J. Canou, L. Dormieux

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

A constitutive model based on generalized elastoplasticity (Zienkiewicz et al., 1985) is used for the modelling of monotonic and cyclic pressuremeter tests in a clay. The permeability of the material is taken into account for the modelling of the excess pore water pressure generation during the test (combination of pore pressure build up and dissipation). It is shown how this type of model can simply represent the main features observed during a cyclic pressuremeter test in a clay, particularly the accumulation of excess pore water pressure during the cycles of loading, and the importance of dissipation on the excess pore …

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