Threshold Shear Strain For Cyclic Degradation Of Three Clays,
2010
National Research Institute for Earth Science and Disaster Prevention, Japan
Threshold Shear Strain For Cyclic Degradation Of Three Clays, Kentaro Tabata, Mladen Vucetic
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Cyclic threshold shear strain, γt, is small cyclic shear strain amplitude above which soil properties significantly change with the number of cycles, N, and below which such changes are for all practical purposes negligible. To date, three cyclic threshold shear strains have been experimentally verified: for cyclic settlement (cyclic compression), for residual cyclic pore water pressure, and for cyclic stiffening. Subject of the paper is testing of fourth cyclic threshold shear strain for cyclic degradation, γtd. When fully saturated soil is subjected in undrained conditions to moderate or large cyclic strain-controlled loading, its secant shear modulus, …
Multi Channel Analysis Of Surface Wave (Masw) Testing For Dynamic Site Characterization Of Delhi Region,
2010
IIIT Hyderabad, India
Multi Channel Analysis Of Surface Wave (Masw) Testing For Dynamic Site Characterization Of Delhi Region, D. Neelima Satyam, K. S. Rao
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
After the Bhuj earthquake the national capital region of Delhi attracted major attention of several scientific studies in the recent times. Since Delhi falls in zone IV (IS 1893: 2002) with high seismic activity, there is a great need for site characterization and seismic hazard mapping of the area. Multi Channel Analysis of Surface Wave (MASW) tests were done in Delhi at 118 sites in predefined grids of 2kmX3km each. Shear-wave velocity, VS, is an important parameter for evaluating dynamic behavior of soil. This test carried outdone using 48 channel digital seismograph with 4.5 Hz geophones. Data was analyzed using …
Comparison Of Dynamic Soil Modelling Using Scpt, Sdmt And Sasw,
2010
Zemin Etud ve Tasarim A.S., Turkey
Comparison Of Dynamic Soil Modelling Using Scpt, Sdmt And Sasw, Kayhan Aykin, Onder Akcakal, H. Turan Durgunoglu, Ozer Akbal
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A site investigation campaign using cone penetration test (CPT), dilatometer test (DMT) are carried on alluvial deposits at a site located at Gemlik, Turkey towards the design of a newly planned hot reverse mill structure within the existing Borçelik steel factory. Site is located at the south of North Anatolian Fault that is sheared during 1999 Kocaeli Earthquake. In addition, the site is under the influence zone of another fault line going through the Gemlik Bay. Therefore, prediction of the behaviour of saturated alluvial deposits under a major expected design earthquake of the planned structures is the prime importance in …
Residual Strength Of Liquefied Sand: Laboratory Vs. Field Measurements,
2010
University of New Hampshire, Durham, NH
Residual Strength Of Liquefied Sand: Laboratory Vs. Field Measurements, Julián Sandoval, Pedro De Alba, Thomas P. Ballestero, Barry K. Fussell
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Determining the residual strength of liquefied sand is essential for estimating post-earthquake stability of vulnerable earth structures, or calculating runout of liquefaction flow slides. Current practice is to select values from a database of back-calculated residual strengths from failure case histories, which have been related to representative penetration test resistance numbers in the failed materials. Given the uncertainties involved, it is desirable to compare the field data with laboratory tests under controlled conditions. This paper describes residual strength measurements for a uniform fine sand using two recently-developed tests designed to impose large strains and strain rates: a modified triaxial test …
Field And Laboratory Tests In Seman Deposits,
2010
Polytechnic University of Tirana, Albania
Field And Laboratory Tests In Seman Deposits, Luljeta Bozo, Skender Allkja, Lorena Harizaj
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The construction of the big energetic park near the spilling of the river needed a geotechnical study to be performed by thoroughly investigations of the sand’s deposits. We would like to present in these papers all the field investigations, laboratory tests and geotechnical study carried out by “ALTEA&GEOSTUDIO2000” laboratory in order to identify the behavior of soils under static and seismic loads. It is possible to create some geotechnical models based on this study and to determine their behavior under static and seismic conditions.
Development Of Database Of Cyclic Soil Properties From 94 Tests On 47 Soils,
2010
University of Rijeka, Croatia
Development Of Database Of Cyclic Soil Properties From 94 Tests On 47 Soils, Leo Matesic, Chu-Chung Hsu, Marco D'Elia, Mladen Vucetic
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Cyclic properties of 47 soils were tested in several investigations between 1994 and 2004 in the standard Norwegian Geotechnical Institute (NGI) direct simple shear (DSS) device and an NGI-type dual-specimen DSS (DSDSS) device for small strain testing. In each investigation many cycles of different amplitude, c, and frequency, f, were applied at different levels of vertical stress, v, and overconsolidation ratio, OCR. In DSDSS device many consecutive series of different small c=0.0003-0.01% were applied on the same specimens without changing their structure, because at such small c cyclic shearing is nondestructive. Consequently, the vast amounts of small-strain data were generated. …
An Insight To The Effect Of Initial Static Shear Stress On The Liquefaction Of Sands,
2010
Sharif University of Technology, Iran
An Insight To The Effect Of Initial Static Shear Stress On The Liquefaction Of Sands, S. Mohsen Haeri, Mehdi Pouragha
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The effect of initial static shear stress on cyclic behavior of sands has been the concern of many researchers for more than five decades. This study includes the results of a set of cyclic simple shear tests carried out on a uniform sand with relative densities of 20%, 40%, and 60%, under three different initial normal stresses of 50, 150, and 250 kPa. All tests were performed under constant volume condition. Results show that the behavior of sands due to initial static shear stress, is controlled by two contradictive elements: first one relates to the increasing dynamic shear modulus due …
Large Scale Model Test For Pile-Supported Wharf In Liquefied Sand,
2010
National Cheng Kung University, Taiwan
Large Scale Model Test For Pile-Supported Wharf In Liquefied Sand, Wen-Jong Chang, Jyh-Fang Chen, Hsing-Chuan Ho
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Pile-supported wharf is a general option in port design to provide lateral resistance and bearing capacity under both static and dynamic loadings. In situ large-scale physical modeling using surface wave generator was performed to study the dynamic soil-structure interactions in pile-supported wharves and to serve as a prototype for in situ monitoring station. A wharf model consisting of 2 steel pipe piles welded on a steel slab was installed on a reconstituted underwater embankment. Due to screening of stress wave, the two piles are subjected to different loading conditions. Data reduction procedures were developed to analyze coupled shear strain-pore pressure …
Reproduction, By Means Of True Scale Testing, Of The Effects Caused On A Track By High Speed Railway Traffic,
2010
Ministerio de Fomento, Spain
Reproduction, By Means Of True Scale Testing, Of The Effects Caused On A Track By High Speed Railway Traffic, Javier Moreno Robles, Vicente Cuéllar Mirasol
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Nowadays, the social importance of the railway transportation is accepted without any doubt, and the levels of comfort and operation quality associated to railways are continuously increasing. The travel times that could be considered allowable in the past century are now obsolete and in order to reduce time “losses”, traffic speeds larger than 300 km/h are being asked for. In order to analyse properly the behaviour of the different layers that make up the railway track structure, the Centro de Estudios y Experimentación de Obras Públicas (CEDEX) of the Ministerio de Fomento, Spain, has built a large facility (5 x …
Resonant-Frequency Method Of Soil Damping Characteristics Determination,
2010
Gersevanov NIIOSP, Russia
Resonant-Frequency Method Of Soil Damping Characteristics Determination, Leonid Stavnitser, Galina Nikitaeva
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The resonant-frequency method of determining the absorption factors characterizing the soil damping properties has been developed for implementation of software programs on computation of dynamic interaction of foundation based constructions. This method is based on processing of amplitude-frequency characteristics of soil samples obtained from the vibro-dynamical tests carried out on the specially constructed installation equipped with the vibro-recording instruments. A set of experiments was performed with sandy and clayey soils at difference humidity, density and stratification depth, based on investigation of forced oscillations of these samples and further processing of the resonance curves within the frames of presentation of the …
Correlation Between Low Strain Shear Modulus And Standard Penetration Test ‘N’ Values,
2010
Indian Institute of Science, India
Correlation Between Low Strain Shear Modulus And Standard Penetration Test ‘N’ Values, P. Anbazhagan, T. G. Sitharam, P. Aditya
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In this study an attempt has been made to develop correlation between standard penetration test (SPT) N values and low strain shear modulus (Gmax). The field experiments of Multichannel Analysis of Surface Wave (MASW) are carried out at 38 locations close to boreholes having Standard Penetration Test N values and in-situ density. These experimental data were generated and used for seismic microzonation of Bangalore, India. In-situ densities of subsurface layers were obtained from undisturbed soil samples collected from the boreholes. Shear wave velocity (Vs) profile with depth were obtained for the same locations or close to the boreholes …
Assessing Cross Anisotropy Of Small-Strain Stiffness Using The Resonant Column Apparatus,
2010
University of Southampton, U.K.
Assessing Cross Anisotropy Of Small-Strain Stiffness Using The Resonant Column Apparatus, Amit K. Sultaniya, Christopher R. I. Clayton, Jeffrey A. Priest, Khairul Anuar Mohd. Nayan, Mohd. Raihan Taha
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Almost all soils exhibit cross-anisotropic stiffness to some extent. However, measuring the cross anisotropic properties of soils is difficult because of the need to determine the 3 independent stiffness parameters Eν, Eh, Gνh, and the associated Poisson’s ratios, nνh and nhh. Current techniques that are employed, for example using bender elements or field geophysics, are not always reliable, whilst preparing specimens in different orientations and subsequent testing using standard laboratory techniques has practical constraints. The resonant column is a laboratory apparatus that has been extensively used to measure the torsional stiffness …
Undrained Response Of Clean And Silty Sands,
2010
University of Western Australia, Australia
Undrained Response Of Clean And Silty Sands, Tejas G. Murthy, Monica Prezzi, Rodrigo Salgado, Dimitrios Loukidis
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
An experimental investigation was undertaken to study the effect of small amounts nonplastic fines on the undrained shear response of sands. Mixtures of Ottawa sand containing 0, 5, 10 and 15% nonplastic silts were studied in a triaxial set up under undrained conditions. The response of the mixtures was summarized based on four characteristic states observed during undrained shearing. These states are the flow liquefaction state, the phase transformation state, the quasi steady state and the critical state. The effects of silt content and initial fabric on relationships describing these characteristic states are highlighted in this paper.
Centrifuge Modeling Of The Influence Of Pre-Existing Fractures In Multilayered Soils On Ground Deformations,
2010
Beijing Seismological Bureau, Beijing, China
Centrifuge Modeling Of The Influence Of Pre-Existing Fractures In Multilayered Soils On Ground Deformations, P. Hu, Y. H. Ding, Q. P. Cai, G. Y. Luo, C. W. W. Ng, Y. J. Hou
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Fault rupture propagation in free fields lays the ground for an understanding of bedrock-soil-structure interactions. Propagation behaviors in dry soil have long been investigated. Localized shear bands have been identified to be the obvious source of failure in dry soils at depth. In addition, numerous subsurface fractures have been found in the field. However, the influence of subsurface fractures in the soil on future seismic faults has received little attention, especially in complex soils. In this study, three centrifuge tests were conducted to investigate the influence of pre-existing fractures on ground deformations in three multilayered soils: three-layered, five-layered and nine-layered …
Vibrodriving Prediction Models Vs. Experimental Results,
2010
Belgium Building Research Institute (BBRI), Belgium
Vibrodriving Prediction Models Vs. Experimental Results, Valérie Whenham, Alain Holeyman
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This paper reviews and discusses methods currently available to assess the vibro-driveability of piles based on a comparison between calculations and experimental observations. The experimental results come from databases collected in Belgium and in The Netherlands, as well as from full scale tests campaigns conducted in Belgium and in France. Discrepancies between modeling assumptions and actual observations are highlighted, and some suggestions are made to improve the performance of design methods.
Increasing Lateral Capacity Of Helical Piles With Lateral Restraint Devices,
2010
Purcell, Rhoades & Associates, Pleasant Hill, CA
Increasing Lateral Capacity Of Helical Piles With Lateral Restraint Devices, John L. Maier, Ali M. Oskoorouchi
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Deflection analysis of piles under lateral live loads in various soil conditions is presented herein. Field testing of lateral capacity was conducted at four test sites in California and Nevada, where weak surface soil provides insufficient lateral capacity for helical piles. In these areas of weak surface soil, as defined by field or laboratory testing, the most feasible solution for a foundation system may be the implementation of a deep foundation system such as a pier and grade beam or helical pile (HP) foundation system. Helical pile diameters that normally range from 1-1/2 to 4 inches provide minimal support when …
Sphere Penetration Experiments In Vertically Vibrated Sand,
2010
Université Catholique de Louvain, Belgium
Sphere Penetration Experiments In Vertically Vibrated Sand, Nicolas Denies, Jean Canou, Jean-Noël Roux, Alain Holeyman
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The paper concerns vibrodriving and vibrocompaction processes applied to granular soils and presents experiments able to characterize the behaviour of sand subjected to vertical vibration. Soil degradation phenomena arising during vibro-driving are first described and the vibro-fluidization of dry granular matter is discussed. The paper concentrates on the shear strength degradation of vibrated dry granular soils. Vertical vibration is then particularly investigated. The volume change during vertical vibration is described and the sand behaviour during vibration is also discussed. One focuses on the influence of the acceleration on the dry density after vibration. Finally, new sphere penetration experiments (SPE) based …
Method To Reduce Variability Of S-Wave Profiles In Seismic Cone Penetration Tests,
2010
Belgian Nuclear Research Centre/ Vrije Universiteit Brussel, Belgium
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 …
P-Wave Reflection Imaging Of Laboratory Soil Models,
2010
University of California, Los Angeles, CA
P-Wave Reflection Imaging Of Laboratory Soil Models, Joseph Coe, Scott J. Brandenberg
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
An ultrasonic p-wave reflection imaging system is used to non-invasively image submerged soil models with embedded anomalies and complex geometric layer contacts. The ultrasonic transducers emit compressive waves into water that subsequently transmit into the underlying soil, and measurements of the reflections are used to construct the images. Properties of the transducers and data acquisition hardware and software are explained. A soil model consisting of embedded high- and low-impedance anomalies, dipping soil layer contacts, and an undulating concrete base layer was imaged using 500 kHz transducers. The geometric features of the model are clearly visible in the images.
A New Method For Evaluating Spatial Variability Of Soil Strains Developed During Earthquakes Based On Electrical Resistivity Concepts Using Green’S Function,
2010
AMEC Geomatrix, Inc., Oakland, CA
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, …
