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Articles 180001 - 180030 of 197988

Full-Text Articles in Engineering

Mechanical Properties Of Cemented Sands Based On Inter-Particle Contact Behavior, Anil Misra, Ching S. Chang Mar 1991

Mechanical Properties Of Cemented Sands Based On Inter-Particle Contact Behavior, Anil Misra, Ching S. Chang

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

The mechanical properties of cemented sands are modelled using a micromechanical approach. The derived model accounts for the packing structure, the particle properties and the contact properties.

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Modelling The Deformation Of Sand During Cyclic Rotation Of Principal Stress Directions, Marte Gutierrez, Kenji Ishihara, Ikuo Towhata Mar 1991

Modelling The Deformation Of Sand During Cyclic Rotation Of Principal Stress Directions, Marte Gutierrez, Kenji Ishihara, Ikuo Towhata

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

The paper presents an elastoplastic constitutive model for the deformation of sand during cyclic rotation of principal stress directions. The model employs a plastic potential theory that allows for the dependency of flow on the stress increment direction and a stress-dilatancy relation incorporating the effects of noncoaxiality. The continuous plastic deformation of sand during principal stress rotation at constant shear stress level is allowed for in the model by using a small elastic area in the stress space. The effects of cyclic stress history is modelled by using discrete surfaces of equal hardening modulus which are allowed to move with …

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Presentation Of The Porewater Pressure Buildup Using Moroto's And State Parameter, Predrag Kvasnička, Tomislav Lvšić Mar 1991

Presentation Of The Porewater Pressure Buildup Using Moroto's And State Parameter, Predrag Kvasnička, Tomislav Lvšić

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

In this paper it is attempted to generate the rise of pore water pressures in undrained strain controlled cyclic triaxial tests for various densities (void ratios), confining pressures and strain amplitudes. The results of cyclic triaxial tests on one type of standard Yugoslav sand are presented. Introducing the Moroto's parameter based on cumulative shear work normalized with confining pressure (Moroto, 1976) and a state parameter defined as a distance between initial void ratio and the steady state line (Been and Jefferies, 1985) the band of the results is narrowed and a single curve for representing the pore water pressure buildup …

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Seismic Downhole, Cpt, And Dmt Correlations In Sand, Thomas G. Thomann, Roman D. Hryciw Mar 1991

Seismic Downhole, Cpt, And Dmt Correlations In Sand, Thomas G. Thomann, Roman D. Hryciw

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

Results from seismic cone penetration and dilatometer tests performed in a cohesionless soil are presented and compared with previously published correlations for estimating the elastic shear modulus. Poor correlations were obtained between the elastic shear modulus, the dilatometer modulus and the cone tip resistance; however, somewhat better estimates of the elastic shear modulus were obtained using the coefficient of lateral stress and total unit weight empirically determined from the dilatometer.

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Stiffness And Damping Parameters For Dynamic Analysis Of Retaining Walls, E. Arni Rafnsson, Shamsher Prakash Mar 1991

Stiffness And Damping Parameters For Dynamic Analysis Of Retaining Walls, E. Arni Rafnsson, Shamsher Prakash

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

The displacements of retaining walls developed during earthquakes have been recognized for many years. Mathematical models have been developed to simulate the behavior of retaining walls during earthquakes. The determination of the soil parameters needed for solution of the displacements has neither been adequately described nor used in a realistic analysis. In this paper theories describing spring and damping constants of rigid retaining walls, for both the base-soil and the back-fill, arc discussed along with the recommended solutions.

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The Dynamic Properties Of Carbonate Sands From Seabed, Du Jian, Wu Xiaofeng, Zhu Longgen Mar 1991

The Dynamic Properties Of Carbonate Sands From Seabed, Du Jian, Wu Xiaofeng, Zhu Longgen

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

Four kind of carbonate sands from offshore seabed together with LB sand of U.K and Fujian sand of China were tested with the Resonant Column method. The results show that the stress strain relationship in the condition of small strain can be represented with the hyperbolic model. The modulus is less than that of general sand. The cementing strength between particles of carbonate sands is weak. The breakage of particles is easy after disturbed and the density, therefore, will be increased. These properties should be further studied for engineering purpose.

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The Influence Of Large Prestrains On Dynamic Properties Of Sand, Richard Wesley Stephenson, S. K. Stringer, K. Sutterer Mar 1991

The Influence Of Large Prestrains On Dynamic Properties Of Sand, Richard Wesley Stephenson, S. K. Stringer, K. Sutterer

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

The development of the UMR Resonant Column/Torsional simple Shear device has provided the means to evaluate high and low amplitude shear moduli on a single sand specimen. Results of cyclic torsional simple shear tests showed that progressive strain increases w1th the cyclic strain amplitude and the number of cycles and decreases with density of the sand. Large accumulated prestrains were found to decrease the maximum dynamic shear modulus by 30 to 35%.

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Variation Of The Soil Geotechnical Properties At Dynamic Loading, Bohumil Svoboda Mar 1991

Variation Of The Soil Geotechnical Properties At Dynamic Loading, Bohumil Svoboda

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

Many experiments of cohesive and noncohesive soils were performed at the special dynamic laboratory Stavebni geologie Prague. The dynamic properties of these roils depend on their internal structure. The cracks of buildings may be observed in earthquake regions if they are constructed on soils that have undergone liquefaction. The special geotechnical investigation may identity these soils.

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Verification By Comparison Between Static And Dynamic Engineering Soil Parameters Evaluated By Means Of Box Tests, Jan Bencat Mar 1991

Verification By Comparison Between Static And Dynamic Engineering Soil Parameters Evaluated By Means Of Box Tests, Jan Bencat

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

A conventional track structure system consists of rails, ties, ballast, subballast and subgrade. To design a track on the basis of live load response and permanent settlement, it is necessary to have knowledge of dynamic stresses in the foundation layers of the track. It needs to determine the material properties and thus, the dynamic and permanent deformation response of the track structure. This paper gives results of the experimental measurements of static and dynamic engineering soil parameters evaluated by means of box tests, Bencat 1989.

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Deformation Of Reconstituted Clay Under Cyclic Loading, S. W. Yan, D. J. Williams Mar 1991

Deformation Of Reconstituted Clay Under Cyclic Loading, S. W. Yan, D. J. Williams

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

Reconstituted soft clay triaxial specimens were prepared by means of vacuum preloading. Both static and cyclic tests were carried out, with the specimens consolidated under different principal effective stress ratios. The test results lend themselves to incorporation in a finite element formulation, which can readily be used for calculating the deformation of soft clay under cyclic loading.

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General Report Session 2: Model Testing In Cyclic Loading, Mladen Vucetic Mar 1991

General Report Session 2: Model Testing In Cyclic Loading, Mladen Vucetic

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

Geotechnical earthquake engineering problems and similar soil dynamics problems usually involve random three directional cyclic loads, complicated stratification of soil deposits and geometry of supported structures, heterogeneity, anisotropy, and nonlinearity of soils, large degradation of soil stiffness and strength accompanied by equally large displacements and deformations, complex interaction between different soil deposits and between the foundation soil and the supported structure, etc. On the other hand, the empirical and analytical methods used in conjunction with standard field testing or standard laboratory cyclic testing on small specimens, which are currently available in engineering practice, are relatively simple and limited to ideal …

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An Alternative Method Of Measuring Spt Energy, Alex Sy, R. G. Campanella Mar 1991

An Alternative Method Of Measuring Spt Energy, Alex Sy, R. G. Campanella

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

Despite problems associated with its repeatability and reliability, the standard Penetration Test (SPT) continues to be the most widely used in-situ test for liquefaction potential assessment. There are many factors known to influence the SPT results but the most significant factor affecting the N value is the amount of hammer energy delivered into the drill rods. The existing method of SPT energy measurement consists of attaching a load cell near the top of the drill rods and measuring the force time history during hammer impact. An alternative method of SPT energy determ1nat1on based on measurement of both force and acceleration …

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An Energy Approach In Defining Soil Liquefaction, J. Ludwig Figueroa, Nitin Dahisaria Mar 1991

An Energy Approach In Defining Soil Liquefaction, J. Ludwig Figueroa, Nitin Dahisaria

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

The concept of energy to define liquefaction has been recognized by several authors. This approach has the advantage over other known methods to define liquefaction of considering a fundamental concept (energy), and of offering the potential of more closely considering random motion effects such as those introduced by earthquake loading. This paper presents the development of relationships between normalized pore pressure and unit energy required to induce liquefaction from testing hollow cylinder sand specimens prepared at different relative densities, and subjected to different confining pressures and shear strain amplitudes. Specimens were tested under constant maximum strain using a sinusoidal torsional …

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Applicability Of Effective Stress Analysis For The Soil-Structure System In Design Practice, Shunji Fujii Mar 1991

Applicability Of Effective Stress Analysis For The Soil-Structure System In Design Practice, Shunji Fujii

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

In the design process of a high rise building in Niigata City, the prediction of liquefaction potential has been conducted by comparing liquefaction resistance obtained from laboratory tests, with shear stress obtained in a total stress analysis of a soil-structure model. As an attempt, one dimensional and two dimensional effective stress analysis were carried out by using a computer program DIANA. By the comparison of these analytical results, the applicability of the effective stress analysis to the actual soil-structure system has been examined.

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General Report Session 3: Deformation And Liquefaction Of Sands, Silt, Gravels And Clays, R. G. Campanella, Alex Sy Mar 1991

General Report Session 3: Deformation And Liquefaction Of Sands, Silt, Gravels And Clays, R. G. Campanella, Alex Sy

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

It has been almost 27 years since the damaging earthquakes of 1964 which occurred in Niigata, Japan and in Alaska, USA, focused the geotechnical engineers' attention to liquefaction as a major problem in earthquake engineering. Considerable research and studies have been conducted on the subject of earthquake induced liquefaction since that time and these have included field observations, laboratory experiments and model tests, and theoretical studies. Progress in understanding the liquefaction phenomenon, in the assessment of liquefaction potential, and in the solutions to mitigate the liquefaction hazard has been made, yet the problem remains controversial in many respects, as reflected …

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Dynamic Properties Of Soft Ground In Shanghai, H.-C. Fei, Y.-W. Wu, R. D. Woods Mar 1991

Dynamic Properties Of Soft Ground In Shanghai, H.-C. Fei, Y.-W. Wu, R. D. Woods

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

Shanghai is located on the east coast of China at the mouth of the Yangtze river at the East China Sea. The alluvial soil deposit at this location is about 300 m deep with an upper soft soil stratum about 100m thick. A study of shear modulus G and damping ratio D of the soft soil stratum has been conducted using Drnevich Resonant Column Device. The test results have been compared with empirical formula for sands established by Hardin and Richart. New empirical relationships for the Shanghai silts and clays are presented.

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Dynamic Strength Of Gravelly Soils And Its Relation To The Penetration Resistance, Y. Tanaka, K. Kudo, K. Kokusho, Y. Yoshida Mar 1991

Dynamic Strength Of Gravelly Soils And Its Relation To The Penetration Resistance, Y. Tanaka, K. Kudo, K. Kokusho, Y. Yoshida

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

Undrained cyclic triaxial tests have been conducted on specimens of dense diluvial gravelly soils taken from four sites by an in-situ freeze sampling method. The test results and previous test results obtained by other researchers suggest that the dynamic strength of gravelly soils can be evaluated based on both the modified blow count of the penetration tests and on the effective confining pressure. A method for the evaluation by utilizing the large penetration test (LPT) blow counts is proposed in this paper by considering the effect of the effective confining pressure on the dynamic strength.

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Efficient Installation Of Gravel Drains, Yoshiro Ono, Yutaka Nakajima, Katsuhiko Ito, Hiroshi Oishi Mar 1991

Efficient Installation Of Gravel Drains, Yoshiro Ono, Yutaka Nakajima, Katsuhiko Ito, Hiroshi Oishi

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

The gravel drain system aims to avert liquefaction in a sandy soil by quickly dissipating excess pore water pressure. We have developed a compaction-rod type machine which allows efficient construction of gravel drains. Main attributes of this machine are: (1) extremely fast installation of gravel drains, (2) low noise, (3) low level of vibration, (4) virtually no ground deformation during construction, and (5) densification of the surrounding soil. Large-scale model tests demonstrated that a cone-type compaction rod is most effective in densifying the surrounding soil when installing gravel drains with our machine.

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Liquefaction Analysis Of Sands: Some Interpretation Of Seed's KΑ (Sloping Ground) And KΣ (Depth) Correction Factors Using Steady State Concept, V. S. Pillai Mar 1991

Liquefaction Analysis Of Sands: Some Interpretation Of Seed's KΑ (Sloping Ground) And KΣ (Depth) Correction Factors Using Steady State Concept, V. S. Pillai

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

Seed's Liquefaction Assessment Chart (SLAC) correlates the corrected SPT blow count (N1)60 to the cyclic stress ratio required to cause liquefaction for free field level ground conditions. However, the cyclic stress ratio or the liquefaction resistance of a soil under sloping ground (initial static shear) and at depth (high confining pressure) would be significantly different from that derived from the SLAC. To correct the liquefaction resistance for the initial static shear and confining pressure, factors Kα and Kσ are used respectively. The factors have significant influence on the evaluation of liquefaction resistance against earthquake loading …

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Liquefaction Ground Deformation Predicted From Laboratory Tests, Mohammed H. Baziar, Ricardo Dobry Mar 1991

Liquefaction Ground Deformation Predicted From Laboratory Tests, Mohammed H. Baziar, Ricardo Dobry

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

A laboratory based approach is described to obtain the post-liquefaction steady-state shear strength of very loose, recently deposited, layered fluvial silty sand deposits susceptible to lateral spreading. Triaxial specimens are formed by the Remolded Discontinuously Vet Pluvial Soil Sample (RDVPSS preparation method. RDWPSS silty sand specimens are prepared by dumping the soil in water and a lowing for segregation and development of layers. Ten undrained tests were conducted using ranges of consolidation pressures σ̅3c = 0.2 to 2.7 kg/cm2 and Kc = σ̅1c/ σ̅3c = 1 to 2. The experiments included both monotonic compression …

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Liquefaction Induced Permanent Ground Displacement In Niigata City, Masanori Hamada, Kazue Wakamatsu, Susumu Yasuda Mar 1991

Liquefaction Induced Permanent Ground Displacement In Niigata City, Masanori Hamada, Kazue Wakamatsu, Susumu Yasuda

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

Permanent ground displacement resulting from the 1964 Niigata Earthquake were studied based on pre- and post-earthquake aerial surveys. In the area along the Shinano River and the Tsusen River, extensive large ground displacements up to about 10 m occurred towards the river, though the ground was almost flat. To ascertain the mechanism of such large ground displacement, several detailed soil investigations were conducted. And it was clarified that the gradient of the ground surface, the gradient of the bottom of the liquefied layer and the thickness of the liquefied layer were main factors affecting to the such large ground displacement.

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Liquefaction Potential Evaluation Based On Rayleigh Wave Investigation And Its Comparison With Field Behavior, Kohji Tokimatsu, Shuji Tamura, Shinichi Kuwayama Mar 1991

Liquefaction Potential Evaluation Based On Rayleigh Wave Investigation And Its Comparison With Field Behavior, Kohji Tokimatsu, Shuji Tamura, Shinichi Kuwayama

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

A simplified method is presented for evaluating liquefaction potential of sand deposits using shear wave velocity. Effectiveness of the proposed method is evaluated through field tests at 17 sites in Niigata city where field performance during the 1964 Niigata earthquake is known. A modified version of steady state Rayleigh wave method is used in which the amplitude ratio between vertical and horizontal ground surface motions can be measured in addition to the phase velocity. Based on the measured phase velocity vs. wavelength relationship, shear wave velocity profile is determined using an inverse analysis. The liquefaction potential of each site is …

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Liquefaction Potential Of Sand Layers In Foundations Of An Embankment Dam, Lrfan Saeed Mar 1991

Liquefaction Potential Of Sand Layers In Foundations Of An Embankment Dam, Lrfan Saeed

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

The liquefaction potential of sand layers present in river bed alluvium underlying a major embankment dam was evaluated under design earthquake conditions. The results of the field and laboratory investigations and dynamic analysis carried out for this purpose are described in the paper. Recommendations made to ensure the post-earthquake safety of the embankment are presented.

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Pore Pressure Response During 1986 Lotung Earthquakes, C. K. Shen, Zhiliang Wang, X. S. Li Mar 1991

Pore Pressure Response During 1986 Lotung Earthquakes, C. K. Shen, Zhiliang Wang, X. S. Li

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

In 1986, two significant earthquake events in Lotung, Taiwan were recorded with both acceleration and pore water pressure traces at different depths below the ground surface. One event (M=6.2) was recorded on July 30th with an epcientral distance of 6km, and the other (M=7.0) was recorded on November 14th with an epicentral distance of about 80 km from the site. To analyze the recorded data, a finite element procedure was developed. The procedure incorporates a newly developed bounding surface hypoplasticity model for granular soils and can handle multidirectional input motions. The finite element procedure takes into consideration pore water pressure …

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Prediction Of Field Sand Liquefaction Caused By Earthquake By Optimum Seeking Method, Du Jian, Zhang Lianyang Mar 1991

Prediction Of Field Sand Liquefaction Caused By Earthquake By Optimum Seeking Method, Du Jian, Zhang Lianyang

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

There are many uncertain factors influencing the field sand liquefaction induced by earthquake, therefore, the predictions of available methods are usually unsatisfactory. In this paper, a new way is developed, i.e., according to the available field sand liquefaction data, the influencing factors are optimized by optimum seeking method, then the prediction is made on the optimized results. By this method, 20 field cases are predicted and the correct rate is 95%. It proves that the suggested method is effective and feasible.

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Prediction Of Liquefaction Behaviour Of Cohesionless Soils, Nakul Dev, Shenbaga R. Kaniraj Mar 1991

Prediction Of Liquefaction Behaviour Of Cohesionless Soils, Nakul Dev, Shenbaga R. Kaniraj

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

In order to mitigate earthquake effects occurring because of soil liquefaction, it is essential that the characteristics of soil deposits prone to liquefaction be reliably assessed. The present paper is an attempt in this direction. Liquefaction behaviour of five sands of different gradation characteristics is evaluated under cyclic simple shear conditions and the results have been used to predict the behaviour of Badarpur sand. Fineness Modulus, and a grain size and gradation factor have been used to predict the cyclic strength. The predicted behaviour is then verified by carrying out simple shear tests on Badarpur sand. As the predicted strength …

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Slides Of River Banks Concerning Lateral Spread Of Liquefaction, Huishan Liu, Chengchuen Wang, Lunian Wong Mar 1991

Slides Of River Banks Concerning Lateral Spread Of Liquefaction, Huishan Liu, Chengchuen Wang, Lunian Wong

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

In this paper 19 cases of river bank slides concerning lateral spread of liquefaction are summarized, some of them are discussed in detail. One of the cases was the lateral spread of liquefied sands by Liao River during Heichen Earthquake (1975, M=7.3). The width of sliding zone in direction perpendicular to the flow was around 500-600m. The second case was about an industrial area in Tianjing, one of the largest cities in China. The land sliding along a silted old course made many buildings cracked and even collapsed. The third case was on liquefaction along Dou River and Luan River. …

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Utilization Of Cone Penetration Test To Evaluate Liquefaction Potential Of Soils, Teparaksa Wanchai Mar 1991

Utilization Of Cone Penetration Test To Evaluate Liquefaction Potential Of Soils, Teparaksa Wanchai

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

A new practical method for evaluation of soil liquefaction by using the Cone Penetration Test (CPT) was proposed. The critical normalized cone resistance, (qcl)cr was presented in terms of cyclic stress ratio, τ/σ0' , and mean grain size of soils, D50. Based on our proposed CPT-based liquefaction assessing correlation, we presented the typical examples of the use and application of CPT to assess liquefaction potential of past earthquake as well as to verify the effectiveness of soil improvement counterrneasured to increase liquefaction resistance of soil.

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Session 4: Discussions And Replies, Multiple Authors Mar 1991

Session 4: Discussions And Replies, Multiple Authors

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

No abstract provided.

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Displacement Based Design Of Retaining Walls, Raj Siddharthan, Prakash K. Gowda, Gary M. Norris Mar 1991

Displacement Based Design Of Retaining Walls, Raj Siddharthan, Prakash K. Gowda, Gary M. Norris

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

A relatively simple rigid plastic model to study deformation behavior of rigid retaining wall is outlined. Both sliding and tilting modes of deformation are included. The study clearly reveals that wall movement caused by tilting can be substantial. But for high values of foundation soil friction angle, the tilting component of deformation can be omitted. Since the wall movement is affected by the characteristics (strength and frequency) of the excitation history, a number of excitation histories should be considered in retaining wall designs.

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