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Articles 4081 - 4110 of 7866

Full-Text Articles in Civil and Environmental Engineering

Numerical Analysis For Seismic Behavior Of A Slope Based On A Simple Cyclic Loading Model, Akihiko Wakai, Keizo Ugai, Masayoshi Sato, Takashi Tazo Mar 2001

Numerical Analysis For Seismic Behavior Of A Slope Based On A Simple Cyclic Loading Model, Akihiko Wakai, Keizo Ugai, Masayoshi Sato, Takashi Tazo

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

A finite element simulation for dynamic centrifuge test of a slope is presented. The horizontal acceleration was applied to the base of the ground, and the response of the slope was measured. The residual deformation, accompanied with a clear slip surface, was observed after the testing. The main objective of this study is to investigate the validity of a new cyclic loading model, based on the strength parameters c - φ, and the G – γ, h - γ relationships. These features are thought to be very useful for practical usage.

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3-D Dynamic Analysis Of Taiyuan Fly Ash Dam, Jian Zhou, Yong Chi, Peijiang Qi Mar 2001

3-D Dynamic Analysis Of Taiyuan Fly Ash Dam, Jian Zhou, Yong Chi, Peijiang Qi

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

In this paper, the seismic stability of Taiyuan Fly Ash Dam in China is studied by using 3-D dynamic effective stress analysis method. The acceleration, dynamic shear stress and pore water pressure in the fly ash dam are calculated and the analysis of the seismic stability of the dam considering the seismic pore water pressure is given for different height of the dam.

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Study On Earthquake-Induced Permanent Deformation Of Earth-Rockfill Dams, Jian-Ming Zhao, Wen-Shao Wang Mar 2001

Study On Earthquake-Induced Permanent Deformation Of Earth-Rockfill Dams, Jian-Ming Zhao, Wen-Shao Wang

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

Based on the experimental data, a three-dimensional (3-D) nonlinear effective stress seismic response analysis method of earth-rockfill dams is proposed with the dissipation and diffusion of seismic pore-water pressure been considered. Then a method for evaluating the earthquake-induced permanent deformation of earth-rockfill dams taking into account both residual shear strain and residual volumetric strain is presented. The method proposed by Taniguchi is adopted to evaluate the earthquake-induced permanent deformation caused by residual shear strain. In order to evaluate the earthquake-induced permanent deformation caused by residual volumetric strain, the saturated part and the non-saturated part of the dams are treated separately. …

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Shaking Table Experiment Of A Model Slope Subjected To A Pair Of Repeated Ground Motions, Joseph Wartman, Jonathan D. Bray, Raymond B. Seed Mar 2001

Shaking Table Experiment Of A Model Slope Subjected To A Pair Of Repeated Ground Motions, Joseph Wartman, Jonathan D. Bray, Raymond B. Seed

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

This paper describes the third of a series of six shaking table experiments conducted as part of ongoing research to evaluate the accuracy and applicability of the Newmark (1965) procedure for computing seismically induced deformation in slopes. A cohesive model slope was shaken by two identical test motions in succession, mimicking a situation that commonly occurs when a preexisting landslide is subjected to strong earthquake shaking. Back analyses of the tests showed that the Newmark (1965) formulation provided moderately accurate estimates of the measured permanent deformations (within 40% to 85% of the maximum measured displacement). The accuracy of the Newmark …

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Is Newmark Method Conservative?, Mohsen Beikae Mar 2001

Is Newmark Method Conservative?, Mohsen Beikae

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

Newmark method is a commonly accepted practice in geotechnical earthquake engineering to estimate seismically induced displacement of earth structures. The method currently requires performing a series of analyses using multiple computer programs to 1) identify a potential sliding mass, 2) compute a factor of safety, 3) calculate a yield acceleration, and 4) perform a double integration of that portion of a given horizontal acceleration history that exceeds the yield acceleration. The Newmark method provides satisfactory results for a horizontal sliding surface. However, for an inclined sliding surface the result is unconservative and for a nonplanar one is not clear. To …

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Dynamic Response Of Dam-Layer System To Earthquake Excitations, Sarada K. Sarma, George Cossenas Mar 2001

Dynamic Response Of Dam-Layer System To Earthquake Excitations, Sarada K. Sarma, George Cossenas

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

An extensive database of ‘free-field’ strong motion records, from rock sites all over the world, of significant strong motion (peak ground acceleration ≥ 0.1 g) has been utilised to identify the dynamic characteristics of a typical dam-layer system. Linear elastic analysis is used to calculate the response of the dam and spectra of average seismic coefficients are presented. Attenuation relationships for the response accelerations along the height of the dam are also presented and the two methods are compared. A rigid-block model is used to calculate the earthquake-induced displacements on the body of the dam, to be used as a …

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Study Of Seismically Induced Landslide Zones, Related To Chamoli Earthquake Of 1999, Garhwal Himalaya, India, H. C. Nainwal, Ajay K. Naithani Mar 2001

Study Of Seismically Induced Landslide Zones, Related To Chamoli Earthquake Of 1999, Garhwal Himalaya, India, H. C. Nainwal, Ajay K. Naithani

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

Landslides are very common in the seismically prone areas of the Garhwal Himalaya. A seismic activity involves displacement either in vertical or horizontal direction and such displacements create slope failure by mass wastings. The maximum impact of Chamoli earthquake was experienced, in the zones of intersection of tear faults with the Main Central Thrust (MCT). During this earthquake large-scale landslides and subsidence caused destruction of many villages located over the hillside slopes. On the basis of field survey pre and post earthquake IRS IC/ID (LISS III/PAN) images, more than 100 slides have been identified in addition to the reactivation of …

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Computational Simulation Procedure For Soil-Structure Interaction Modeling In Building Seismic Damage Response, Ismail M. Ismail, Chris Mullen Mar 2001

Computational Simulation Procedure For Soil-Structure Interaction Modeling In Building Seismic Damage Response, Ismail M. Ismail, Chris Mullen

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

A finite element based computational procedure is presented for soil-structure interaction modeling in building seismic response. Attention is focused on a combination of contact surfaces at the soil-foundation interface, nonlinear soil material and infinite elements as transmitting boundary conditions. A rationale for efficient mesh design is offered for the building/foundation/soil system model based on computational wave propagation studies using infinite elements. As a the proposed procedure, a comparison is made between results of eigen mode analysis of two models for a 3-story office building, with the conventional treatment of the foundation and soil as discrete linear springs [3], and …

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Design Concept For High Speed Railway Bridges In Regions With High Seismic Activity And Soft Soil, Oliver Fischer, Andreas Maurial, Konstantin Meskouris, Carsten Könke, Falko Schube Mar 2001

Design Concept For High Speed Railway Bridges In Regions With High Seismic Activity And Soft Soil, Oliver Fischer, Andreas Maurial, Konstantin Meskouris, Carsten Könke, Falko Schube

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

At present, public transport for mid distances is more and more covered by modern high speed railway links with many examples all over the world being already under construction or in the design process. In case of soft soil conditions or urban areas, many of these projects are being realized as an elevated railway structure utilizing regular viaducts. In seismic active regions earthquake design mainly governs the overall design concept of the bridges, particularly of the piers and foundations. Thus, on the one hand, the structure has to exhibit enough stiffness under serviceability conditions (limitation of rail stresses; safety requirements …

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Dynamic Soil-Foundation-Structure Interaction Analyses Of Large Caissons, C.-Y. Chang, Chin-Man Mok, Z.-L. Wang, R. Settgast, C.-C. Chin, H. M. Gonnermann, F. Waggoner, M. A. Ketchum Mar 2001

Dynamic Soil-Foundation-Structure Interaction Analyses Of Large Caissons, C.-Y. Chang, Chin-Man Mok, Z.-L. Wang, R. Settgast, C.-C. Chin, H. M. Gonnermann, F. Waggoner, M. A. Ketchum

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

Large cellular reinforced concrete caissons exist as foundations of major long-span bridges across waterways in many parts of the country. This study was conducted to evaluate the important factors affecting the seismic response of large caissons. The paper presents the results of equivalent linear and non-linear analyses performed for a typical caisson idealized based on the cellular caisson at Pier W3 of the West San Francisco Bay Bridge subject to ground motion with a peak rock acceleration of 0.6 g. This caisson is 38.7 m (127 fi) long by 22.9 m (75 ft) wide submerged in about 32.6 m (107 …

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Dynamic Soil-Pile-Structure Interaction, Yingcai Han Mar 2001

Dynamic Soil-Pile-Structure Interaction, Yingcai Han

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

The largest compressor train in North America was installed for a new ethylene production plant at the Nova Chemicals Facility located near Joffre, Alberta. To illustrate the effect of soil-pile-structure interaction, the dynamic behavior of the structure using flexible piled foundation is compared to the same structure fixed to a rigid base in this paper. Both field and laboratory tests were carried out to investigate the soil properties including down hole seismic tests to provide soil shear wave velocities at different depths. Different design options are considered and an optimum design selected to limit vibration and produce a safe, economic …

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Seismic Analysis Of Tunnel Surrounded By Soft Soil In Shanghai, Jian Zhou, Xiaoyan Hu, Yong Chi Mar 2001

Seismic Analysis Of Tunnel Surrounded By Soft Soil In Shanghai, Jian Zhou, Xiaoyan Hu, Yong Chi

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

Based on the test results, the analysis of earthquake resistance of tunnel surrounded by soft soil in Shanghai is presented in this paper. The tunnel is located in the soft soil and sand, respectively. The reaction acceleration, pore water pressure and the settlement of the tunnel under 7-degree earthquake are given and compared.

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Effect Of Anisotropy On Drained And Undrained Shear Behavior Of In-Situ Sandy Soils, Akihiko Uchida, Munenori Hatanaka, Yuji Taya Mar 2001

Effect Of Anisotropy On Drained And Undrained Shear Behavior Of In-Situ Sandy Soils, Akihiko Uchida, Munenori Hatanaka, Yuji Taya

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

Two different types of undisturbed cylindrical specimen (V-specimen: the axis is parallel to the direction of sedimentation, and H-specimen: the axis is perpendicular to the direction of sedimentation), were prepared from high quality undisturbed sand column obtained by in-situ freezing technique. A series of drained compression and extension tests (CD, test, CD, test) and cyclic undrained triaxial tests (liquefaction test) on these samples were performed in order to investigate the effect of the anisotropy on the drained and undrained shear behavior. Following were concluded. 1) The effect of anisotropy on both internal friction angle and liquefaction strength is negligible. 2) …

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Seismic Response Calculation Of Saturated Soft Soil, Huang Yu, Ye Weimin, Tang Yiqun, Chen Zhuchang Mar 2001

Seismic Response Calculation Of Saturated Soft Soil, Huang Yu, Ye Weimin, Tang Yiqun, Chen Zhuchang

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

In this paper, Shanghai saturated soft soil is modeled as a two-phase porous media system consisting of solid and fluid phases. On the basis of resonant column test and dynamic triaxial test data of Shanghai saturated soft soil, the dynamic calculation model including a set of relationships of stress, strain, and pore water pressure and earthquake subsidence is developed to compute the seismic response of soil. The procedure to identify soil constants for the dynamic calculation model is also reported in detail. Subsequently, a dynamic effective stress analysis with the finite element method has been recommended to predict the seismic …

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Soil Viscous Behavior In Response To Torsional Cyclic Loading, Jiang Li Mar 2001

Soil Viscous Behavior In Response To Torsional Cyclic Loading, Jiang Li

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

In the present paper, experimental investigations of dynamic behavior of soils under periodic loading are conducted. Investigations include two aspects. First, effect of confining pressure and loading frequency on soil dynamic behavior and stress-strain relation is studied. Second, effect of confining pressure, loading frequency and amplitude of cyclic shear stress on soil viscosity is investigated. In the first aspect, based on test curves, physical nonlinearity shown in soil stress-strain relation suggests that physical parameters of soil materials are not constant. For example, soil elastic parameters can be a function of cyclic shear strain, confining pressure and loading frequency. In the …

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Application Of Fk Analysis Of Surface Waves For Geotechnical Characterization, Sebastiano Foti, Renato Lancellotta, Laura V. Socco, Luigi Sambuelli Mar 2001

Application Of Fk Analysis Of Surface Waves For Geotechnical Characterization, Sebastiano Foti, Renato Lancellotta, Laura V. Socco, Luigi Sambuelli

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

Since the introduction of the SASW method the use of surface waves for soil characterization has gained great popularity in geotechnical engineering. The typical two-receiver testing configuration shows some inherent drawbacks, for this reason a multistation approach is proposed in this paper. The dispersion curve evaluation with a multistation scheme has several advantages. First of all, the estimate is much more stable and less sensitive to noise and internal phases of the instruments. Moreover signal interpretation is much clearer with respect to SASW approach and there is no need for subjective choices in the construction of the experimental dispersion curve. …

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Static And Dynamic Properties Of Leighton Buzzard Sand From Laboratory Tests, Antonio Cavallaro, Michele Maugeri, Rosalia Mazzarella Mar 2001

Static And Dynamic Properties Of Leighton Buzzard Sand From Laboratory Tests, Antonio Cavallaro, Michele Maugeri, Rosalia Mazzarella

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

The Leighton Buzzard sand is an English sand commonly used at the University of Bristol to study soil-shallow foundation interaction (Maugeri et al., 1999a; 199b) and soil-retaining wall interaction (Carafa et al., 1998) by means of the shaking table. These experiments require an accurate definition of geotechnical characterisation of soil. To define the mechanical behaviour of uncemented Leighton Buzzard sand a large number of static and dynamic laboratory tests were performed on dry reconstituted specimens. The static tests includes direct shear tests performed on specimens reconstituted by pluvial deposition method with different relative density Dr. To evaluate the …

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Prediction Of Volumetric Strain For Sand Under Cyclic Loading, Habib Shahnazari, Ikou Towhata Mar 2001

Prediction Of Volumetric Strain For Sand Under Cyclic Loading, Habib Shahnazari, Ikou Towhata

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

In order to investigate volume change of sand due to cyclic loading, different tests were performed on hollow cylindrical specimens under drained cyclic simple shear condition. Correlation of accumulated plastic shear energy with volumetric strain and effects of different parameters such as initial confining pressure, initial anisotropic consolidation and strain amplitude on this correlation were studied. Test results showed that volumetric strain of sand under different initial confining pressures was almost same. Volume change of specimens with different initial anisotropic consolidations was also identical, except for initial stage of shearing. It was found that the correlation of volumetric strain and …

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Influence Of Micro-Structure On Small-Strain Stiffness And Damping Of Fine Grained Soil And Effects On Local Site Response, Anna D'Onofrio, Francesco Silvestri Mar 2001

Influence Of Micro-Structure On Small-Strain Stiffness And Damping Of Fine Grained Soil And Effects On Local Site Response, Anna D'Onofrio, Francesco Silvestri

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

Various experimental studies have shown that soil micro-structure strongly influences the small strain stiffness and damping (G0, D0) of fine-grained soils, as well as their variation with shear strain γ. This dependency, in turn, is expected to influence the local site response. This paper firstly synthesizes the dependency of G0 and D0 on stress state through power relationships, expressed in terms of dimensionless parameters, obtained by fitting a large number of experimental data collected on normally consolidated natural clays. Thereafter, these parameters were correlated to soil micro-structure, by assuming the plasticity index Ip …

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Suggestion Of Empirical Equations For Damping Ratio Of Plastic And Non-Plastic Soils Based On The Previous Studies, Dugkeun Park, Harry E. Stewart Mar 2001

Suggestion Of Empirical Equations For Damping Ratio Of Plastic And Non-Plastic Soils Based On The Previous Studies, Dugkeun Park, Harry E. Stewart

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

Several empirical correlations between damping ratio with various factors are available and many researchers have developed empirical correlations between damping ratio and normalized shear modulus. Regardless of the appearance of the equations, the estimation of the damping ratio from the normalized shear modulus at any given shear strain amplitude is possible. In this paper, thirty-two sets of normalized shear modulus versus damping ratio from ten references are used to find a new empirical equation for damping ratio of sandy soils. For clayey soils, more than forty sets of normalized shear modulus versus damping ratio from nine references are used. After …

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Cyclic Torsional Shear Tests On Liquefaction Resistance Of Sands Under Low Confining Stress, Jinichi Koseki, Daisuke Itakura, Sadahiro Kawakami, Takeshi Sato Mar 2001

Cyclic Torsional Shear Tests On Liquefaction Resistance Of Sands Under Low Confining Stress, Jinichi Koseki, Daisuke Itakura, Sadahiro Kawakami, Takeshi Sato

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

A series of undrained cyclic torsional shear tests was conducted to investigate the effects of initial confining stress level on liquefaction resistance of sand. Hollow-cylindrical dense specimens with outer diameter of 10 cm, inner diameter of 6 cm and height of 20 cm are prepared with two kinds of sand. After being saturated, they were isotropically consolidated under an initial confining stress σc’ of 4.9, 9.8 or 98 kPa, and subjected to undrained cyclic torsional shear while maintaining the axial and lateral stresses constant. The amplitude of the cyclic torsional shear stress τcy was kept constant with …

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The Influence Of Lateral Faults In The Nonlinear Analysis In An Alluvionar Valley, Marcel Vasile Sincraian, Carlos Sousa Oliveira, J. V. Lemos Mar 2001

The Influence Of Lateral Faults In The Nonlinear Analysis In An Alluvionar Valley, Marcel Vasile Sincraian, Carlos Sousa Oliveira, J. V. Lemos

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

The nonlinear dynamic behavior of an alluvionar valley situated in São Sebastão region in Terceira island (Azores archipel) is performed. The Mohr-Coulomb model is used in this paper. A bidimensional cross-section with 1240 m long and 250 m depth is considered. The cross-section of the model is composed by layers having different type of ground, each one having their own geotechnical characteristics. The Distinct Element method is employed in this case. UDE Code is used. The size of Finite Elements has been tailored to the wavelength of the propagating waves through the layers. The objectives of this paper are: 1) …

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Improvement Of Static And Dynamic Properties Of Soft Clay Using High Pressure Jet Grout, Chang Tzyy-Shiou, Vedula V. Ramakumar, Chang Kuo-Ping Mar 2001

Improvement Of Static And Dynamic Properties Of Soft Clay Using High Pressure Jet Grout, Chang Tzyy-Shiou, Vedula V. Ramakumar, Chang Kuo-Ping

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

A proposed subway project is located in an area marked by a number of soft clay layers situated at depths from 60 ft to 100 ft below the ground surface. With unconfined compressive strength less than 0.6 tsf these natural soils are not strong enough to support on coming heavy loads and vibrations that the subway may be subject to in future. Hence the soil was trial grouted in-situ using high pressure jet grout technique to improve the engineering properties of the natural clay. A series of static and dynamic property tests were carried out on 18 samples selected from …

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Plasticity Based Liquefaction Criteria, Carmine Polito Mar 2001

Plasticity Based Liquefaction Criteria, Carmine Polito

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

Since their introduction into Chinese building codes in the 1970’s, plasticity-based liquefaction criteria have provided a means for evaluating the liquefaction susceptibility of sands with clayey fines. These criteria are used to separate soils that may be considered non-liquefiable from those susceptible to liquefaction. The majority of the proposed criteria contain some minimum requirement regarding clay content and soil plasticity. The results of a parametric study into the effects of plastic fines content and plasticity on the liquefaction susceptibility of sandy soils were used to evaluate the accuracy of several of the more commonly used plasticity-based liquefaction criteria. Most of …

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Dynamic Loading-Deformation Performance Of Peat Soil Under Large Concrete Plates, Mark Vakher Mar 2001

Dynamic Loading-Deformation Performance Of Peat Soil Under Large Concrete Plates, Mark Vakher

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

This paper presents data from a series of investigations performed with peat soil to determine resilient deformation under dynamic load, which has great influence on the design of connections between concrete plates that are used as pavement for rural roads. The experiments were performed both in situ and under laboratory conditions using a concrete plate, size 3m by 1 m by 0.15m placed over peat. Other experiments were made with the concrete plate placed over the various thicknesses of sand fill above the surface of peat soil. Experiments were carried out under dynamic load. The laboratory experiments were conducted with …

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A Review Of The Influence Of Initial State Shear (KΑ) And Confining Stress (KΣ) On Failure Mechanisms And Earthquake Liquefaction Of Soils, V. S. Pillai, B. Bmuhunthan Mar 2001

A Review Of The Influence Of Initial State Shear (KΑ) And Confining Stress (KΣ) On Failure Mechanisms And Earthquake Liquefaction Of Soils, V. S. Pillai, B. Bmuhunthan

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

Geotechnical engineering profession has continued to use the in situ measurement based empirical procedure to perform soil liquefaction analysis. This method was initially developed based on past earthquake performance of level ground sites. For sloping ground and larger depths or confining stress, the method requires appropriate corrections such as Kα for initial static shear and Kσ for confining stress. The recommended correction factors in the current state of practice have been presented by NCEER (National Center for Earthquake Engineering and Research). These recommendations, however, do not distinguish between the distinct shear behavior of soils on the opposite sides …

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Automated Analysis Procedure For Interpreting Results From Impulse Shear Tests, Wanda Henke, Robert Henke Mar 2001

Automated Analysis Procedure For Interpreting Results From Impulse Shear Tests, Wanda Henke, Robert Henke

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

In this paper, we present and discuss an automated analysis procedure for interpreting results from torsional cylindrical impulse shear tests. The “impulse shear test” is an in situ geotechnical test that provides detailed information on in situ nonlinear inelastic shearing deformation characteristics needed for dynamic geotechnical earthquake engineering analysis procedures. The test addresses the issue of effects of disturbances to in situ conditions. The automated analysis procedure is intended to be a major improvement over our existing approach for interpreting results from impulse shear tests. We demonstrate the automated analysis procedure by using the procedure to interpret results from impulse …

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Measurement Of Shear Modulus Profile Using A Continuous Surface Wave Measurement System, S. Anand, E. C. Leong, H. K. Cheong Mar 2001

Measurement Of Shear Modulus Profile Using A Continuous Surface Wave Measurement System, S. Anand, E. C. Leong, H. K. Cheong

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

For most ground response analyses, the shear modulus is an important parameter to be determined and it has to be measured over a large strain range, so as to characterise the soil behavior under various loading conditions. Laboratory measurement of shear modulus covers a limited strain range depending on the test method. The main difficulty lies in the determination of the shear modulus at very small strains. In this respect, geophysical methods are more attractive. One of these test methods, which uses a continuous surface wave, is used to obtain the shear modulus profile at two sites in Singapore. The …

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Post-Liquefaction Torsion Shear Tests On Sand With Various Strain Rates, Kiyoshi Kokeguchi, Atusushi Shimokawa, Jun Kohchi, Ikuo Towhata Mar 2001

Post-Liquefaction Torsion Shear Tests On Sand With Various Strain Rates, Kiyoshi Kokeguchi, Atusushi Shimokawa, Jun Kohchi, Ikuo Towhata

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

This text concerns with the deformation characteristics of liquefied sand which undergoes large residual deformation and flow failure. In particular, the nature of sand which can be used in a dynamic analysis of deformation in the time domain is aimed at. Although the former model tests have suggested a rate-dependent behavior of sand, a detailed measurement of stress and strain was not possible. This problem was overcome in the present study in which two types of torsional shear device were employed. A special care was therein taken to achieve such a large and realistic shear strain as 100% in a …

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Identification Of Small Strain Dynamic Properties Of Dense Sand, Ahmed Elgamal, Tao Lai, Dan Wilson, Bruce Kutter Mar 2001

Identification Of Small Strain Dynamic Properties Of Dense Sand, Ahmed Elgamal, Tao Lai, Dan Wilson, Bruce Kutter

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

System identification techniques are employed to characterize the stiffness and damping characteristics of a dense sand stratum at low dynamic excitation conditions. The identification process utilizes a large database of input-output accelerations recorded in a highly instrumented centrifuge experimental program conducted by researchers at the University of California at Davis. This paper presents a computational effort based on the recorded small shaking events, where the peak ground surface acceleration ranges from 0.05g to 0.196g in amplitude. The dynamic behavior of the prototype stiff soil site near its first resonance is modeled by that of a one-dimensional shear beam. An employed …

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