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Liquefaction Studies Of The Solani Sand Reinforced With Geogrid, Swami Saran, B. K. Maheshwari, H. P. Singh May 2010

Liquefaction Studies Of The Solani Sand Reinforced With Geogrid, Swami Saran, B. K. Maheshwari, H. P. Singh

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

In this paper, a study on liquefaction resistance of Solani sand reinforced with geogrid sheets is reported. Tests were carried out on shake table (vibration Table) with sand samples prepared at relative density of 25% without and with geogrid sheets. In this investigation biaxial synthetic geogrid sheets having the dimension equal to plan dimension of the shake table tank were used in three different combinations of 3 layers, 4 layers and 5 layers at different depths within the sand sample. The liquefaction parameters such as maximum pore water pressure (Umax), maximum pore water pressure built up time (t …


On The Influence Of The Grain Size Distribution Curve On Dynamic Properties Of Quartz Sand, Torsten Wichtmann, Theodor Triantafyllidis May 2010

On The Influence Of The Grain Size Distribution Curve On Dynamic Properties Of Quartz Sand, Torsten Wichtmann, Theodor Triantafyllidis

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

The paper reports on our effort to extend the well-known Hardin's equation by the influence of the grain size distribution curve. The study is motivated by the fact that Hardin's equation with its commonly used constants can significantly over-estimate the small strain shear modulus Gmax of well-graded sands. Approximately 350 resonant column (RC) tests with additional P-wave measurements have been performed on 33 specially mixed grain size distribution curves of a quartz sand with different mean grain sizes d50, coefficients of uniformity Cu = d60/d10 and fines contents FC. The experiments show that …


Procedure To Evaluate Liquefaction-Induced Lateral Spreading Based On Shear Wave Velocity, Fred (Feng) Yi May 2010

Procedure To Evaluate Liquefaction-Induced Lateral Spreading Based On Shear Wave Velocity, Fred (Feng) Yi

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

Evaluation of liquefaction-induced lateral spreading is very important for the design of structures located on gently sloping ground and with relatively shallow groundwater. Extensive research has been performed on the calculation of liquefaction-induced lateral spreading based on the standard penetration test (SPT) and cone penetration test (CPT) data by various researchers (Bartlett and Youd 1992, 1995, Rauch, 1997; Zhang et al., 2004; Idriss and Boulanger, 2008). However, few published papers can be found that address the calculation of liquefaction-induced lateral spreading based on shear wave velocity. This paper presents a procedure to evaluate liquefaction-induced lateral spreading directly based on shear …


Recovery Of Elastic Parameters For Cross-Anisotropic Sandy Soil Via Elastic Wave Measurements, Omer Faruk Capar, Isao Ishibashi May 2010

Recovery Of Elastic Parameters For Cross-Anisotropic Sandy Soil Via Elastic Wave Measurements, Omer Faruk Capar, Isao Ishibashi

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

In this study, the elastic properties of loose to medium dense (Dr=50%) sandy soil were obtained from elastic wave propagation techniques in the laboratory. The soil specimens were assumed cross anisotropic medium. Two bender elements are embedded in the top cap and the pedestal of the triaxial device as receivers and transmitters in the vertical direction for P- and S-waves. In addition, two bender elements are attached to the membrane surrounding the soil specimen to measure horizontal P-wave velocities. After the preparation of the specimens, vertical and horizontal P-wave velocities and a vertical shear wave velocity were measured under different …


Resonant Frequency Of Model Footings Resting On Finite Saturated Sand Stratum, H. N. Ramesh, M. T. Prathap Kumar May 2010

Resonant Frequency Of Model Footings Resting On Finite Saturated Sand Stratum, H. N. Ramesh, M. T. Prathap Kumar

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

The resonant frequency of the foundation-soil system depends on several factors and nonhomogeniety of soil is one of the important factors that include the effect of saturation. In the present investigation, the effect of saturation and location of rigid concrete base on the resonant frequency of foundation-soil system was determined by conducting vertical vibration test on model footings resting on the surface of finite dry sand stratum as well as on finite saturated sand stratum underlain by rigid concrete base. On the basis of the experimental investigation, it was concluded that the presence of rigid base at shallow depth decreases …


Seismic Behavior Of Nailed Soil Massifs, V. A. Barvashov, Ch. A. Dzhantimirov, I. M. Iovlev, P. V. Kharlamov, S. A. Rytov May 2010

Seismic Behavior Of Nailed Soil Massifs, V. A. Barvashov, Ch. A. Dzhantimirov, I. M. Iovlev, P. V. Kharlamov, S. A. Rytov

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

Soil nailing technology can be successfully applied to strengthen natural soil massifs in seismic regions, provided adequate analysis is available. Conventionally, the design of soil nailing is performed iteratively: firstly parameters of nailing and their distribution are assigned, the safety factor of the nailed massif is calculated, if its value is less than 1 then nailing parameters are reassigned, etc. Such “trial and error” approach is laborious and especially so, because different types of ULSs shall be analyzed. The method, discussed in the paper, is based on assumption that the effect of nailing in soil with internal cohesion c=c(x,y) could …


Shearing Rate Effect On Mechanical Behavior Of Msw Materials, Nader Shariatmadari, Sandro Lemos Machado, Ali Noorzad, Mehran Karimpour Fard, Mohsen Keramati, Seyyed Hossein Jafari Kalarijani May 2010

Shearing Rate Effect On Mechanical Behavior Of Msw Materials, Nader Shariatmadari, Sandro Lemos Machado, Ali Noorzad, Mehran Karimpour Fard, Mohsen Keramati, Seyyed Hossein Jafari Kalarijani

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

Recent catastrophic failure in different regions of the world is an indication on the poor level of engineering knowledge on the mechanical behavior of MSW materials which are the main materials in the landfill body. However extensive researches have been made to represent a clear frame work to describe the behavior of these materials but clearly all of these attempts had not been enough. In the region with high seismic activity, mechanical response of MSW materials under quick and dynamic loading condition is one of the issues which should be addressed however there are some evidences concerning the higher resistance …


Simplified Theoretical Analysis Of The Seismic Response Of Artificially Compacted Gravels, Giuseppe Modoni, Anna Gazzellone May 2010

Simplified Theoretical Analysis Of The Seismic Response Of Artificially Compacted Gravels, Giuseppe Modoni, Anna Gazzellone

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

Despite extensive use of gravely materials for the construction of big earthworks, theoretical prediction of their seismic response is often based on very simple schemes, unable to reproduce most of the important features observed at sample scales. Theoretical models capable of simulating the effects of artificial compaction on the stress-strain response of these soils under complex static and dynamic loading conditions would be particularly useful for designing more cost effective solutions in the construction of large embankments. This paper is aimed to fill this gap by reporting the results of a simplified theoretical study on the seismic response of an …


Small Strain Properties Of Sands With Different Cement Types, Luling Yang, Lynn Salvati May 2010

Small Strain Properties Of Sands With Different Cement Types, Luling Yang, Lynn Salvati

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

This research examines the small strain properties of Ottawa, Monterey and Michiana sands cemented in the laboratory with two different cementing agents using flush mounted transducers, bender elements, and resonant column tests. Samples cemented with higher strength cementing agents and higher cement contents had higher maximum shear modulus values and greater nonlinearity in the shear modulus reduction and damping curves. Although confining pressure is a significant factor for the small strain stiffness of uncemented sands, it did not affect the maximum shear modulus or the shear modulus reduction curves of the cemented sands tested. The density of the cemented samples …


Soil Improvement Techniques For Mitigation Of Seismic Hazards - An Overview, Ram Prasad Sharma May 2010

Soil Improvement Techniques For Mitigation Of Seismic Hazards - An Overview, Ram Prasad Sharma

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

If seismic hazards are deemed to be unacceptably high because of poor soil conditions, it is often possible to achieve improved seismic performance through the use of one or more soil improvement techniques. Poor performance is the result of inadequate strength, low stiffness, or insufficient drainage. Many improvement techniques have been evolved over the years, mostly through trial and error, aimed at improving at least one of these properties. When selecting one or more mitigation methods, it is important to consider the effectiveness of the improvement approach for the particular situation at hand, cost, environmental consequences, regulatory requirements, and technical …


The Effect Of Nonplastic Silt Gradation On The Liquefaction Behavior Of Sand, Mehmet Murat Monkul, Jerry A. Yamamuro May 2010

The Effect Of Nonplastic Silt Gradation On The Liquefaction Behavior Of Sand, Mehmet Murat Monkul, Jerry A. Yamamuro

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

Various researchers have published results regarding the effect of non plastic silts on the liquefaction behavior of sands. Some concluded that increasing fines content decrease the liquefaction potential, whereas others observed the opposite. Some of those discrepancies might be explained via various factors such as different confining stresses, different depositional methods, different consolidation histories and possibly different comparison bases (i.e. void ratio, intergranular void ratio, relative density). New experimental results from monotonic undrained triaxial compression tests performed on Nevada Sand-A mixed with different silts indicate that liquefaction behavior is also significantly influenced by the gradation of the fines.


The Universal Void Ratio Function For Small Strain Shear Modulus, Man T. Bui, C. R. I. Clayton, Jeffrey A. Priest May 2010

The Universal Void Ratio Function For Small Strain Shear Modulus, Man T. Bui, C. R. I. Clayton, Jeffrey A. Priest

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

Small strain shear modulus, Gmax, is a key parameter representing the small strain response of soils under seismic load. It is also an important parameter in design of foundations where only small deformation takes place. It is recognised that Gmax is significantly influenced by void ratio. The influence of void ratio on Gmax of a soil has been taken into account by using an empirical void ratio function, F(e), and various forms of F(e) have been proposed. However, each F(e) can only be applied for a given soil within a limited void ratio range. There was …


Threshold Shear Strain For Cyclic Degradation Of Three Clays, Kentaro Tabata, Mladen Vucetic May 2010

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, D. Neelima Satyam, K. S. Rao May 2010

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, Kayhan Aykin, Onder Akcakal, H. Turan Durgunoglu, Ozer Akbal May 2010

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, Julián Sandoval, Pedro De Alba, Thomas P. Ballestero, Barry K. Fussell May 2010

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, Luljeta Bozo, Skender Allkja, Lorena Harizaj May 2010

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, Leo Matesic, Chu-Chung Hsu, Marco D'Elia, Mladen Vucetic May 2010

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, S. Mohsen Haeri, Mehdi Pouragha May 2010

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, Wen-Jong Chang, Jyh-Fang Chen, Hsing-Chuan Ho May 2010

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, Javier Moreno Robles, Vicente Cuéllar Mirasol May 2010

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, Leonid Stavnitser, Galina Nikitaeva May 2010

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, P. Anbazhagan, T. G. Sitharam, P. Aditya May 2010

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, Amit K. Sultaniya, Christopher R. I. Clayton, Jeffrey A. Priest, Khairul Anuar Mohd. Nayan, Mohd. Raihan Taha May 2010

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, Tejas G. Murthy, Monica Prezzi, Rodrigo Salgado, Dimitrios Loukidis May 2010

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, P. Hu, Y. H. Ding, Q. P. Cai, G. Y. Luo, C. W. W. Ng, Y. J. Hou May 2010

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, Valérie Whenham, Alain Holeyman May 2010

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, John L. Maier, Ali M. Oskoorouchi May 2010

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, Nicolas Denies, Jean Canou, Jean-Noël Roux, Alain Holeyman May 2010

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, 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 …