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Geotechnical Engineering Commons

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2010

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Articles 301 - 330 of 432

Full-Text Articles in Geotechnical Engineering

Method To Reduce Variability Of S-Wave Profiles In Seismic Cone Penetration Tests, Lou Areias May 2010

Method To Reduce Variability Of S-Wave Profiles In Seismic Cone Penetration Tests, Lou Areias

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

The pseudo method used to calculate shear wave velocity (Vs) in seismic cone penetration (SCP) tests often generates high variability of Vs values at shallow depths. This occurs when travel paths are small and signal variability large to allow accurate arrival time differentiation between successive signals. The offset distance between the source and receivers has the largest influence on signal variability. A method described in this paper shows good results in reducing Vs variability of SCP tests during post processing. The method consists of increasing the sampling interval to calculate Vs and then regrouping the data …


A New Method For Evaluating Spatial Variability Of Soil Strains Developed During Earthquakes Based On Electrical Resistivity Concepts Using Green’S Function, Zhihua Li May 2010

A New Method For Evaluating Spatial Variability Of Soil Strains Developed During Earthquakes Based On Electrical Resistivity Concepts Using Green’S Function, Zhihua Li

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

A new method for evaluating spatial variability of soil strains during earthquakes is developed. The idea is based on electrical resisitivity concepts. By solving the classic Maxwell’s equations applying Green’s function for the boundary conditions, we obtained a closed form solution relating the electric potential measurements to the soil’s displacements during earthquakes. The displacement information can be further used to obtain soil strains. In centrifuge models, the displacement measurements using an electrode switching system have been demonstrated to have spatial and temporal resolutions of 1 mm and 1 ms. Based on the high resolution of the displacement that is obtainable, …


Applicability Test Of Soil Improvement Using Micro-Bubbles Against Soil Liquefaction, Koichi Nagao, Naoaki Suemasa, Tatsuo Akashi, Mikio Futaki May 2010

Applicability Test Of Soil Improvement Using Micro-Bubbles Against Soil Liquefaction, Koichi Nagao, Naoaki Suemasa, Tatsuo Akashi, Mikio Futaki

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

The purpose of this paper is to demonstrate the effectiveness of micro-bubble water injection method against soil liquefaction based on the result of seismic vibration test using large scale flexible shaking box. It is well known that soil resistance to liquefaction increases as the degree of saturation of the soil decreases, but the practical method to decrease the saturation of the soil has not been invented. The authors solved this problem by new method of injecting water containing micro-air bubbles into the ground. The method has an advantage which not only simple and cost-effective but also friendly to environment. We …


Shake Table Testing To Quantify Seismic Soil-Structure-Interaction Of Underground Structures, Robb Eric S. Moss, Vic Crosariol, Steven Kuo May 2010

Shake Table Testing To Quantify Seismic Soil-Structure-Interaction Of Underground Structures, Robb Eric S. Moss, Vic Crosariol, Steven Kuo

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

This research uses shake table testing of scale soil-structure models to mimic the coupled seismic response of underground structures and surrounding/supporting soil (termed soil-structural-interaction or SSI). Currently the seismic design of subways and other critical underground infrastructure rely on little to no empirical data for calibrating numerical simulations. This research is working towards filling that empirical data gap. The research is composed of two phases, the first a validation of the free-field response of a flexible wall barrel filled with model soil, the second a test to measure the “racking” deformations induced in a model subway cross-section embedded in the …


Dynamic Behavior Of An Elastic Beam On A Winkler Foundation Under A Moving Load, Abdul Hayir May 2010

Dynamic Behavior Of An Elastic Beam On A Winkler Foundation Under A Moving Load, Abdul Hayir

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

The purpose of this study is to investigate the response of an elastic beam on a Winkler foundation under a moving load. The load is assumed as a moving harmonic load and the beam is considered as an infinite Bernoulli-Euler beam with constant cross-section. The approach of Winkler foundation for the elastic foundation is very common in the practical applications although it does not accurately represent the continuous characteristic of the foundations. In this model the interaction between the vertical springs is only considered. In the solutions of the problem, the double Fourier Transform is applied and for its invention …


Geotechnical Seismic Isolation By Scrap Tire-Soil Mixtures, Hing-Ho Tsang, Nelson T. K. Lam, Saman Yaghmaei-Sabegh, M. Neaz Sheikh, Buddhima Indraratna May 2010

Geotechnical Seismic Isolation By Scrap Tire-Soil Mixtures, Hing-Ho Tsang, Nelson T. K. Lam, Saman Yaghmaei-Sabegh, M. Neaz Sheikh, Buddhima Indraratna

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

The stockpiling of scrap tires is a significant threat to our environment and has been a hot topic amongst the engineering community which has been looking for long term viable solutions to the recycling and reuse of rubber tires. This paper proposes a new method of utilizing scrap tires for applications in infrastructure protection forming part of the solution strategy. The method involves mixing scrap tire particles with soil materials and placing the mixtures around civil engineering systems, for vibration absorption. The inexpensive nature of the proposed method can be of great benefits to developing countries where there are affordability …


Large Variation In Pga Due To Presence Of Heterogeneities In The Surface Soil, Mohammad Ahmed Hussain, Ramancharla Pradeep Kumar May 2010

Large Variation In Pga Due To Presence Of Heterogeneities In The Surface Soil, Mohammad Ahmed Hussain, Ramancharla Pradeep Kumar

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

In the proximity of an active fault, spatial variation of peak ground motion is significantly affected by the faulting mechanism. It has been observed that near fault ground motions consists of different characteristics compared to the far fault ground motions. Near fault records, in the distance range of less than 100 m from the faults are not available except for few cases. Therefore numerical simulation of ground motions for such near-fault situations is necessary. There is a need to enhance our understanding of the possible potential hazard that can be caused due to the future rupture activity by understanding the …


Mechanical And Acoustical Vibrations Of A Building Generated By Weaving Looms, Ion Vlad May 2010

Mechanical And Acoustical Vibrations Of A Building Generated By Weaving Looms, Ion Vlad

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

Dynamic excitations and the resulting stresses in a weaving mill can affect its functioning in many different ways. Possible consequences of service vibrations include emission of acoustic waves, reduction of product quality, damage of non-structural elements (especially partition walls and cladding) and the disturbance of the activity in buildings placed in close vicinity. It is difficult to identify the influence of the vibrations on the production, on the weaving shed and on the neighborhoods. In 2004, an Italian company has rented in Romania 6000 square meters in a huge, one level industrial building, in order to lay out a weaving …


3-D Modeling Of Shear-Wave Velocity For Numerical Green’S Function In Near-Field Ground Motion Simulation, Xiaodan Sun, Xiaxin Tao, Lijun Yin, Dongli Zhang May 2010

3-D Modeling Of Shear-Wave Velocity For Numerical Green’S Function In Near-Field Ground Motion Simulation, Xiaodan Sun, Xiaxin Tao, Lijun Yin, Dongli Zhang

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

Numerical Green’s function is effective for simulating low-frequency ground motions in the near field, in which the whole computing region is divided into a homogenous zone including the source and an inhomogeneous zone (named overburden layer) from the ground surface to a certain depth. In this paper, a procedure to build a 3-D model that properly describes the shear-wave velocity structure of overburden layer and the topography of ground surface was presented. In this procedure, the overburden layer is discretized into finite elements based on the topography of ground surface and buried rock surface; shear-wave velocity data from inversion, surveying …


Aggravation Of The Peak Seismic Acceleration In The Vicinity Of 2d Hills, Canyons And Slopes, Achilleas G. Papadimitriou, Yannis Chaloulos May 2010

Aggravation Of The Peak Seismic Acceleration In The Vicinity Of 2d Hills, Canyons And Slopes, Achilleas G. Papadimitriou, Yannis Chaloulos

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

This paper studies the topographic aggravation of the peak seismic acceleration in the horizontal and vertical directions for various cases of 2D uniform surface geometries: hills, canyons and slopes. The study is based on a large number of 2D wave propagation analyses for uniform soil conditions performed with the finite-difference method. All analyses were visco-elastic, assumed vertically impinging harmonic SV waves and studied parametrically the effects of the slope inclination i, the dimensionless height H/λ of the topographic feature (where H is the height and λ is the predominant S wavelength) and of the width B of the canyon base …


Model Validation Of Recent Ground Motion Prediction Relations For Shallow Crustal Earthquakes In Active Tectonic Regions, James Kaklamanos, Laurie G. Baise May 2010

Model Validation Of Recent Ground Motion Prediction Relations For Shallow Crustal Earthquakes In Active Tectonic Regions, James Kaklamanos, Laurie G. Baise

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

Recent earthquake ground motion prediction relations, such as those developed from the Next Generation Attenuation of Ground Motions (NGA) project in 2008, have established a new baseline for the estimation of ground motion parameters such as peak ground acceleration (PGA), peak ground velocity (PGV), and spectral acceleration (Sa). When these models were published, very little was written about model validation or prediction accuracy. We perform statistical goodness-of-fit analyses to quantitatively compare the predictive abilities of these recent models. The prediction accuracy of the models is compared using several testing subsets of the master database used to develop the NGA models. …


Numerical Analysis Of Trampoline Effect In Extreme Ground Motion, Tetsuo Tobita, Susumu Iai, Tomotaka Iwata May 2010

Numerical Analysis Of Trampoline Effect In Extreme Ground Motion, Tetsuo Tobita, Susumu Iai, Tomotaka Iwata

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

Very large vertical surface acceleration of nearly four times gravity was measured at a strong motion observation station in Iwate Prefecture during the 2008 Iwate-Miyagi Inland, Japan, earthquake (Mw 6.9). The station is located about 3 km southwest of the epicenter and equipped with three-component accelerometers, installed at both the free surface and the bottom of a 260-m borehole. The wave form of the vertical acceleration shows a clearly asymmetric form with large amplitude in the upward direction. Aoi et al. (2008) reported and qualitatively explained the mechanism of this phenomenon by the analogy of bouncing a piece of …


Uniform Hazard Response Spectra Of Korea Considering Uncertainties In Ground Properties, Dong-Yeop Kwak, Duhee Park, Bang Woong Shin, Kwangkyun Kim May 2010

Uniform Hazard Response Spectra Of Korea Considering Uncertainties In Ground Properties, Dong-Yeop Kwak, Duhee Park, Bang Woong Shin, Kwangkyun Kim

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

The seismic site coefficients derived deterministically are often used with ground motion parameters determined by probabilistic seismic hazard analysis in construction of the design response spectrum. There is, therefore, an inherent incompatibility between two approaches. New methods have been developed to resolve this incompatibility by developing probabilistic seismic site coefficients. In such approaches, the uncertainties in the properties of the ground were not systematically accounted for due to lack of measurements of the ground. In this study, an integrated probabilistic seismic hazard analysis which can quantify the nonlinear seismic site effects and account for the uncertainties in soil properties is …


1d Dynamic Non-Linear Numerical Analysis Of Earth Slopes: The Role Of Soil Ductility And Time-Sensitiveness, Claudio Giulio Di Prisco, Federico Pisanò May 2010

1d Dynamic Non-Linear Numerical Analysis Of Earth Slopes: The Role Of Soil Ductility And Time-Sensitiveness, Claudio Giulio Di Prisco, Federico Pisanò

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

The mechanical response of dry granular slopes subjected to dynamic perturbations is tackled from a theoretical/numerical viewpoint. A 1D geometrical/numerical scheme is adopted to analyze infinitely long strata: the dynamic activation of shallow translational failure mechanisms (as well as the displacement performance far from collapse) is analyzed by means of a self-made FEM code. The soil mechanical behavior is described by means of a simplified viscoplastic one-dimensional constitutive model, capable of reproducing both ductile (hardening) and brittle (softening) mechanical responses. The dependence of numerical results on the soil “time-sensitiveness”, as well as the differences between viscoplasticity and standard rate-independent plasticity, …


Nonlinear Site Effects: Interest Of One Directional - Three Component (1d - 3c) Formulation, Maria Paola Santisi D’Avila, Jean-François Semblat, Ali Gandomzadeh, Fabian Bonilla, Luca Lenti, Salvatore Martino May 2010

Nonlinear Site Effects: Interest Of One Directional - Three Component (1d - 3c) Formulation, Maria Paola Santisi D’Avila, Jean-François Semblat, Ali Gandomzadeh, Fabian Bonilla, Luca Lenti, Salvatore Martino

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

Strong ground motions generally lead to both a stiffness reduction and a larger energy dissipation in the soil layers. Thus, in order to study such phenomena, several nonlinear rheologies have been developed in the past. However, one of the main difficulties of using a given rheology is the number of parameters needed to describe the model. In this sense, the multi-surface cyclic plasticity approach, developed by Iwan in 1967 is an interesting choice since the only data needed is the modulus reduction curve. Past studies have implemented this method in one-directional SH wave-propagation (1D-1C). This work, however, aims to study …


Seismic Site Response Analysis Using Spreadsheets, Geraldo R. Iglesia, James L. Stiady May 2010

Seismic Site Response Analysis Using Spreadsheets, Geraldo R. Iglesia, James L. Stiady

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

A spreadsheet-based framework for quantifying local site response due to seismic excitation is presented in this paper. The main focus here is on equivalent-linear one-dimensional analysis, similar to the computer program SHAKE or its derivative kin, which by far is the most commonly used approach for performing ground response evaluation. Such analysis involves the computation of the response of a semi-infinite horizontally layered deposit overlying a uniform half-space subjected to vertically propagating shear waves. The bulk of the analysis is actually carried out in the frequency domain, which involves operations with complex-algebraic parameters. Widely available spreadsheet software is typically equipped …


A Study Of Effective Factors On The Behavioural Characteristics Of Clayey Sands, Omid Naeemifar, S. Shahaboddin Yasrobi May 2010

A Study Of Effective Factors On The Behavioural Characteristics Of Clayey Sands, Omid Naeemifar, S. Shahaboddin Yasrobi

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

As in recent years liquefaction phenomena have occurred in sandy soils containing different amounts of clay contents, it was concluded that in addition to silty sands, clayey sands are also vulnerable to liquefaction phenomenon. So, the urge for comprehensive study aroused to cover the issue. In this paper, the effect of clay content and its plasticity properties on behavioural characteristics of clayey sands under various density and confining pressure values have been investigated. To achieve the goal, about a hundred monotonic triaxial tests were performed on remoulded specimens of sandy soils containing different clay contents with different plasticity values. Based …


Assessment Of Liquefaction-Induced Foundation Soil Deformations, K. Onder Cetin, Berna Unutmaz, H. Tolga Bilge May 2010

Assessment Of Liquefaction-Induced Foundation Soil Deformations, K. Onder Cetin, Berna Unutmaz, H. Tolga Bilge

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

Although there exist some consensus regarding seismic soil liquefaction triggering assessment of free field soil sites, estimating the liquefaction triggering potential beneath building foundations still stays as a controversial and a difficult issue. Assessing liquefaction triggering potential under building foundations requires the estimation of cyclic and static stress state of the soil medium. In the recent studies (e.g. Unutmaz 2008), the cyclic stress ratio corrected for Kα and Kσ effects under and adjacent to building foundations subjected to cyclic loading are to be estimated with the help of a series of 2-D and 3-D numerical simulations for different …


Comparison Of Three Procedures For Evaluating Earthquake-Induced Soil Liquefaction, John Liao, Jorge Meneses, Emre Ortakci, Zia Zafir May 2010

Comparison Of Three Procedures For Evaluating Earthquake-Induced Soil Liquefaction, John Liao, Jorge Meneses, Emre Ortakci, Zia Zafir

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

Over the past decade, major advances have occurred in both the understanding and the practice with regard to the evaluation of soil liquefaction potential during earthquakes. Among these advances, there are two analytical frameworks (i.e., Seed et al. (2003) and Idriss and Boulanger (2008) procedures), which are widely accepted by the industry. The most significant achievement of the new procedures is their new criteria for assessment of liquefaction potential of low-plasticity silts and clays. These two new procedures are changing the way the design and regulatory communities consider soil liquefaction evaluation and may likely become standard-ofpractice in the near future. …


Equivalent Granular Void Ratio And Behaviour Of Loose Sand With Fines, Md. Mizanur Rahman, Sik-Cheung Robert Lo, Misko Cubrinovski May 2010

Equivalent Granular Void Ratio And Behaviour Of Loose Sand With Fines, Md. Mizanur Rahman, Sik-Cheung Robert Lo, Misko Cubrinovski

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

Traditionally, void ratio is being used as a state variable for liquefaction analysis of sand with fines. However, recent publications reported that void ratio is not a good state variable for sand with fines. Thus, equivalent granular void ratio, e* instead of void ratio, e is proposed to resolve this problem. A single trend for Steady State (SS) data points for sand with fines can then be achieved in e*- log(p') space irrespective of fines contents, fc. The single trend is referred to as equivalent granular steady state line, EG-SSL. However, a parameter b, the active fraction of …


Estimating Seismic Parameters Associated With Previous Earthquakes By Scptu Soundings In The Nmsz, Tianfei Liao, Paul W. Mayne May 2010

Estimating Seismic Parameters Associated With Previous Earthquakes By Scptu Soundings In The Nmsz, Tianfei Liao, Paul W. Mayne

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

Although the New Madrid seismic zone (NMSZ) is the most active seismic region in the eastern United States, paleoliquefaction features are often used to analyze the previous seismic activities, due to the long recurrence interval of large earthquakes. A new methodology is proposed in this paper to estimate the seismic parameters associated with previous earthquakes based on the results of seismic cone penetration tests (SCPT), using the simplified procedure of liquefaction analysis and the attenuation relationships developed for the corresponding seismic areas. This methodology is validated through the paleoliquefaction studies at two sites associated with the 1989 Loma Prieta earthquake …


Liquefaction Countermeasure Technique By Using Logs For Carbon Storage Against Global Warming, Masaho Yoshida, Masakatsu Miyajima, Atsunori Numata May 2010

Liquefaction Countermeasure Technique By Using Logs For Carbon Storage Against Global Warming, Masaho Yoshida, Masakatsu Miyajima, Atsunori Numata

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

Global warming is one of the most serious problems which faced by civil engineers in this century. Because a wood can store carbon within itself, the utilization of wood in the construction projects may contribute to the mitigation of global warming. The technique of ground improvement by installing logs into loose sand layer as a countermeasure against soil liquefaction was proposed in this study. The logs had been used as pile foundation until 1950's in Japan. However, as the wood has high possibility of a decrease in strength by decay, the utilization of wood become minority in the construction projects. …


Liquefaction Mitigation Of Three Projects In California, Tom M. Farrell, Kyle Wallace, John Ho May 2010

Liquefaction Mitigation Of Three Projects In California, Tom M. Farrell, Kyle Wallace, John Ho

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

Ground displacements resulting from earthquake-induced soil liquefaction and dynamic densification can cause moderate to severe structural damage during and after an earthquake. Geotechnical construction methods of mitigating these potential ground displacements include mass excavation and replacement with engineered fill, ground improvement such as soil mixing, jet grouting, compaction piers, vibro compaction, vibro stone columns, and deep dynamic compaction, or deep foundations such as driven piles. The ground improvement methods rely on altering the soil properties to resist the seismically-induced shear stresses and soil grain redistribution while deep foundation methods bypass liquefiable soil deposits to found in deeper competent soil or …


Microscale Characterization Of Energy Dissipation Mechanisms During Liquefaction, Usama El Shamy, Christina Denissen May 2010

Microscale Characterization Of Energy Dissipation Mechanisms During Liquefaction, Usama El Shamy, Christina Denissen

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

This study utilizes the discrete element method (DEM) to present a microscopic energy monitoring approach to characterize energy dissipation mechanisms in seismically loaded soils. Numerical simulations were conducted on saturated deposits of granular particles subjected to seismic excitations, modeled using a transient fully-coupled continuum-fluid discrete-particle model. The onset of liquefaction is illustrated through macroscopic and microscopic response patterns. An in-depth look at the individual microscale energy components both before and after the onset of liquefaction is presented. Prior to liquefaction, energy is dissipated mainly through inter-particle sliding (friction energy), but after liquefaction particle-to-particle impact damping also plays a major role …


Recent Advances In Liquefaction Of Fine Grained Soils, Shamsher Prakash, Vijay K. Puri May 2010

Recent Advances In Liquefaction Of Fine Grained Soils, Shamsher Prakash, Vijay K. Puri

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

Paper reviews present literature recommendations on liquefaction of soils with fines starting with the experimental evidence previously published by the authors. The liquefaction behavior of silts and silt clay mixers was investigated over a range of plasticity index values of interest by conducting cyclic triaxial tests on reconstituted samples and their behavior was compared with that of sand. It was found that saturated silts with plastic fines behave differently from sands both with respect to rate of development of pore water pressure and axial deformations with number of load cycles. The results also showed that liquefaction susceptibility of silts shows …


Residual Shear Strengths Of Cohesionless Soils From Energy Approach, Raghvendra Singh, Debasis Roy May 2010

Residual Shear Strengths Of Cohesionless Soils From Energy Approach, Raghvendra Singh, Debasis Roy

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

The residual shear strength of the non plastic soils are generally estimated from the correlations between residual shear strength estimated from the laboratory tests or from the back analyses of post failure geometries of case histories distressed during static or seismic loading and penetration resistances. The post failure shear strength of large deformed structures like debris flow, mud flow and avalanches in which the post deformed soil mass gain large distance after the failure, depends on the strain rate behavior of shear (viscous) resistance, frictional resistance, inertial effect, three dimensional effect of geometry, flexibility of failed material and void redistribution …


Seismic Analysis Of Saturated Sand Deposits With Silt Layers, Murat Tonaroglu, Kutay Ozaydın, S. Umit Dikmen May 2010

Seismic Analysis Of Saturated Sand Deposits With Silt Layers, Murat Tonaroglu, Kutay Ozaydın, S. Umit Dikmen

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

Liquefaction of saturated sands during earthquakes is known to be the cause of significant earthquake related damages, including loss of bearing capacity, lateral flow and spreading, slope failures. In recent earthquakes including the1999 Marmara Earthquake in Turkey, field observations have indicated that silt inclusions or silt layers in the sandy deposits can have significant effects on development of liquefaction. The objective of this work is to analytically study the behavior of saturated sand deposits with silt layers. For this purpose, a hypothetical soil profile in which silt layers exist has been selected. The selected profile was then modeled and analyzed …


Undrained Response And Liquefaction Behaviour Of Non-Plastic Silty Sands Under Cyclic Loading, K. Ranga Swamy, A. Boominathan, K. Rajagopal May 2010

Undrained Response And Liquefaction Behaviour Of Non-Plastic Silty Sands Under Cyclic Loading, K. Ranga Swamy, A. Boominathan, K. Rajagopal

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

The undrained response and liquefaction behaviour of fine sand and silty sands consisting of 30% and 50% non-plastic fines were investigated in the present study. The effect of consolidation stress level, cyclic stress amplitude and amount of non-plastic fines on soil liquefaction have been studied through a systematically planned stress controlled cyclic triaxial tests. To examine the effect of consolidation pressure on liquefaction behaviour, the sand-silt specimens were prepared at 40% relative density and consolidated at pressures of 50, 100 and 200 kPa. To investigate the effect of fines content on liquefaction resistance of sands at constant postconsolidation void ratio, …


3d Analysis Of The Seismic Response Of Seven Oaks Dam, Lelio Mejia, Ethan Dawson May 2010

3d Analysis Of The Seismic Response Of Seven Oaks Dam, Lelio Mejia, Ethan Dawson

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

Procedures for the three-dimensional (3-D) dynamic analysis of earth dams have been available for over 25 years. However, additional case histories are needed to assess whether such procedures are capable of simulating the seismic response of dams in narrow canyons, and to further evaluate the effects of 3-D behavior on the response of such dams. This study was aimed at identifying the vibration characteristics of Seven Oaks Dam during the 2005 Yucaipa and 2001 Big Bear Lake earthquakes, and at evaluating the applicability of 3-D and 2-D numerical procedures to simulate the response of the dam. Accelerograms recorded on the …


Behavior Of Nailed Steep Slopes In Laboratory Shake Table Tests, Aniruddha Sengupta, Debabrata Giri May 2010

Behavior Of Nailed Steep Slopes In Laboratory Shake Table Tests, Aniruddha Sengupta, Debabrata Giri

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

This paper presents results of laboratory shake table tests performed to study the dynamic behavior of nailed steep slopes. The surface displacements, settlement of the crest and the acceleration responses along with the behavior of the facing wall are examined during the tests. Two 18 cm high 60° and 70° steep soil slopes reinforced with nine hollow aluminum nails placed in three rows are considered. Three strain gauges are glued to each nail to measure the tensile force developed in the nails. Four strain gauges are fixed at the center of the facing wall to measure the development of strains …