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Articles 11341 - 11370 of 13030

Full-Text Articles in Engineering

Dynamic Properties Of Saturated Coal Fly Ash, Pei-Ji Yu, Wei-Qin Qin Mar 1991

Dynamic Properties Of Saturated Coal Fly Ash, Pei-Ji Yu, Wei-Qin Qin

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

The great part of fly ash produced by thermal power plants is either sluiced or filled in disposal areas in China. The dynamic properties of fly ash are important for solving geotechnical problems relating to fly ash mass under dynamic loadings. The high temperature during combustion makes fly ash nonplastic but pozzolanic. The nonplasticity causes the dynamic properties of sluiced and just compacted fly ash to be similar to ones of silts. The pozzolanic action causes obvious aging effect for compacted fly ash, by which an aging time of 180 days may increase maximum shear modulus by 75% to 400% …

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Effects Of Hysteretic Shape On Dynamic Response, Per B. Selnes, Farrokh Nadim Mar 1991

Effects Of Hysteretic Shape On Dynamic Response, Per B. Selnes, Farrokh Nadim

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

The parameters determined in laboratory tests for use in dynamic analyses are usually the secant modulus and the area of the hysteresis loop. The accuracy of this approach was studied for highly non-linear behavior through analytical solutions and numerical simulations of a single degree of freedom system. Only the effect of the shape of the hysteresis loop was studied, i.e. the stiffness and the area of the loop were kept constant independent of amplitude. The study shows that irregular hysteresis may cause a significant increase in the response of the system in higher frequencies compared to what would be expected …

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In Situ And Laboratory Tests For The Evaluation Of Dynamic Geotechnical Properties Of A Cohesive Deposit In Florence, T. Crespellani, G. Vannucchi, A. Ghinelli Mar 1991

In Situ And Laboratory Tests For The Evaluation Of Dynamic Geotechnical Properties Of A Cohesive Deposit In Florence, T. Crespellani, G. Vannucchi, A. Ghinelli

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

In order to determine dynamic parameters to use for seismic microzoning purposes in a new development area near Florence, the dynamic behavior of the alluvial silty clays situated in the upper 60 m of the deposit was experimentally investigated using geophysical surveys and cyclic laboratory tests. Previous studies on the geotechnical properties of the clays of Florence revealed that, in spite of some similarities in a comparison with other coeval clays described in the literature this soil exhibits a few anomalies, as e.g. higher variations between field and laboratory shear waves velocities and remarkable differences in the coefficients of the …

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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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Structural Collapse Behavior Of Sands In Undrained Shear, J. D. Frost, J. L. Chameau, G. A. Leonards Mar 1991

Structural Collapse Behavior Of Sands In Undrained Shear, J. D. Frost, J. L. Chameau, G. A. Leonards

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

Results from undrained torsional shear tests are presented and used to further examine the concepts of steady state and structural collapse in sands, with emphasis on the influence of the collapse mechanism on soil behavior at steady state. It is shown that the degree to which the material collapses is dependent on the loading conditions and the initial fabric of the sand. Consequently, the steady state position in the state diagram is also function of these parameters.

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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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Cyclic Strength Evaluation Of Rockfill Dams, Farhat H. Siddiqi, Richard J. Fragaszy Mar 1991

Cyclic Strength Evaluation Of Rockfill Dams, Farhat H. Siddiqi, Richard J. Fragaszy

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

A method of modeling the cyclic behavior of gravelly soils containing particles too large to be tested in standard laboratory equipment has been described. This matrix model is based on the understanding that oversize particles floating in a matrix of smaller grains can be removed without significantly affecting the cyclic behavior of the total soil. Successful modeling of the total soil requires that the matrix be tested at the same relative density as that of the total material. Cyclic triaxial test results on two different gravelly soils are presented. Results of tests performed on the total soil with maximum grain …

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Experimental Study On Lateral Flow Of Ground Due To Soil Liquefaction, Yasushi Sasaki, Hideo Matsumoto, Ken-Ichi Tokida, Syoichi Saya Mar 1991

Experimental Study On Lateral Flow Of Ground Due To Soil Liquefaction, Yasushi Sasaki, Hideo Matsumoto, Ken-Ichi Tokida, Syoichi Saya

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

A series of shake table tests is carried out on the lateral flow of the ground due to soil liquefaction during earthquakes. The model grounds are 6.0 m long, 0.8 m wide and their average height is 1.2 m. The slope of the ground surface and the lower boundary condition of liquefiable layer are varied, and the sinusoidal accelerations with a frequency of 2 Hz are inputted for 20 seconds. The deformation of model grounds, the excess pore water pressure of the liquefied layer, and the acceleration of the grounds are monitored. Based on the test results, the influence of …

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Laboratory Tests On Embedded Reactor Building On Hard Ground, Hiroshi Hibino, Masanori Izumi, Ken'ichi Moriyama, Yukiharu Kiya Mar 1991

Laboratory Tests On Embedded Reactor Building On Hard Ground, Hiroshi Hibino, Masanori Izumi, Ken'ichi Moriyama, Yukiharu Kiya

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

In order to experimentally confirm the dynamic characteristics of embedded reactor building, shaking table tests and hammering tests were carried out, utilizing hard ground model made of hard silicone rubber and structural model made of aluminum which is embedded by soft silicone rubber. From the test results, it was confirmed that embedment increases system frequency of soil- structure interaction system, the ratio of elastic deformation of structure and radiation damping. Using the transient data of impulse responses, impedance function and foundation input motion could be identified in a smooth shape. Simulated results for non-embedded case by wave propagation theory and …

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Large Scale Field Tests On Quaternary Sand And Gravel Deposits For Seismic Siting Technology, Makota Watabe, Takaaki Konno, Masao Hayashi, Sadao Suzuki, Kenji Ishihara, Koji Kitazawa, Kinji Akino, Yoshio Suzuki, Setsuo Iizuka, Takashi Matsuda, Tetsuichi Ukita, Kiyonari Mori, Tsutomu Yamazaki, Kiyoshi Nagai Mar 1991

Large Scale Field Tests On Quaternary Sand And Gravel Deposits For Seismic Siting Technology, Makota Watabe, Takaaki Konno, Masao Hayashi, Sadao Suzuki, Kenji Ishihara, Koji Kitazawa, Kinji Akino, Yoshio Suzuki, Setsuo Iizuka, Takashi Matsuda, Tetsuichi Ukita, Kiyonari Mori, Tsutomu Yamazaki, Kiyoshi Nagai

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

The basic policy of Japan is to build nuclear reactor building on bed rock. But, in order to cope with the middle and long term siting problems it has become necessary to promote new siting technology from the standpoint of expanding the available range of site selections and effective utilization of land. The large scale field tests were conducted at the Tadotsu Engineering Laboratory, Kagawa Prefecture, of The Nuclear Power Engineering Test Center (NUPEC) as an entrusted project into the Siting Methods on Quaternary Deposits from the Ministry of International Trade and Industry (MITI), in order to verify the seismic …

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Shaft Resistance During Driving In Clay From Laboratory Tests, A. Ben Amar, D. Levacher, Ph. Lepert, P. Boisard Mar 1991

Shaft Resistance During Driving In Clay From Laboratory Tests, A. Ben Amar, D. Levacher, Ph. Lepert, P. Boisard

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

This paper presents a laboratory study which aimed at investigating the soil/pile interaction during driving. A short review of past experimental works justifies the need for more consistent data. The test equipment (a rod driven through a sample of soil) is briefly presented and some signals are displayed to illustrate the quality of the measurements. The tests were performed on samples of normally consolidated Kaolinit clay. The analysis of the stress waves propagating in the rod, during driving, provided a good estimation of interaction forces, bar velocities and displacements of the pile model in the sample. Relationships were established between …

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Tunnel Damage Resulting From Seismic Loading, J. S. Phillips, B. A. Luke Mar 1991

Tunnel Damage Resulting From Seismic Loading, J. S. Phillips, B. A. Luke

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

Correlation of ground motion to observed tunnel damage has largely been based on estimates of ground motion rather than observations and measurements. In an effort to provide a data set that included both measured ground motions and documented tunnel response, an experiment was designed and fielded 0.5 km from a recent underground nuclear explosion (UNE) which had a body wave magnitude, mb, and a Richter local magnitude, ML, of 5.0. The data obtained in this experiment are summarized in the paper. The discussion centers on the applicability of the results of this experiment to the design …

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An Elastoplastic Model For Sand Liquefaction, Limin Zhang, Ting Hu Mar 1991

An Elastoplastic Model For Sand Liquefaction, Limin Zhang, Ting Hu

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

The stress-dilatancy relations of sand for the stress paths involved in a complete periodic stress cycle are set up. The plastic potential functions for' each loading stage are derived consequently. Based on the idea of using a stress-strain relationship as an alternative strain-hardening law, the drained volume changes under different effective stress paths are derived and verified. A pore pressure generation mechanism which can take into account the dilatancy of soli directly and the related computational model are put forward. The model can calculate the instantaneous and residual pore pressures in sand and depict the liquefaction process of sand quantitatively, …

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Deformation Of Coarse Materials Associated With Cyclic Loadings, Jiro Kuwano, Shih-Chang Chen Mar 1991

Deformation Of Coarse Materials Associated With Cyclic Loadings, Jiro Kuwano, Shih-Chang Chen

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

A series of static and cyclic triaxial tests was carried out on compacted greywacke sandstone containing small amount of fines. Permanent strain of saturated or air-dried sample induced by cyclic loading was measured for different cyclic loading sequences, initial shear stress, and fine content. The shear deformation and strength of those samples were also investigated by monotonic loading on virgin and post-cyclic loading samples.

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Session 3: Discussions And Replies, Multiple Authors Mar 1991

Session 3: Discussions And Replies, Multiple Authors

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

No abstract provided.

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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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Energy Approach For Liquefaction Of Sandy And Clayey Silts, Y. L. Cao, K. T. Law Mar 1991

Energy Approach For Liquefaction Of Sandy And Clayey Silts, Y. L. Cao, K. T. Law

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

The liquefaction potential of sandy and clayey silts is assessed in this paper using an energy approach original developed for sand. Three series of laboratory tests were conducted to examine the liquefaction resistance of clean silt, sandy silt and clayey silt. The test results have been analyzed to establish a liquefaction failure criterion for silty soils. Based on this criterion, the case records of a new database have been studied and the results suggest that a single criterion can be used for sand, silt, sandy silt and clayey silt. For sandy or silty soils without clay content, the criterion is …

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Liquefaction Fragilities For Buried Lifelines, Jose A. Pires, A. H.-S. Ang, I. Katayama Mar 1991

Liquefaction Fragilities For Buried Lifelines, Jose A. Pires, A. H.-S. Ang, I. Katayama

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

For buried structures, such as conduits and underground pipes, liquefaction induced forces will depend on the volume of soil surrounding the structure that will liquefy. Here, a methodology to calculate the probability of the onset of liquefaction at a given depth in a soil deposit is extended to assess the probability that a specified volume of soil will liquefy when liquefaction occurs at a given depth in the deposit. To account for the variability of soil properties with depth, the soil deposit is divided into horizontal layers and the volume of liquefied soil in each layer is calculated as the …

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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 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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Mechanical Characterization Of The Threshold Strain In Sand Liquefaction, A. Kaddouri Mar 1991

Mechanical Characterization Of The Threshold Strain In Sand Liquefaction, A. Kaddouri

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

DOBRY et al, YOUD have shown the existence of a shearing threshold strain in the vicinity of 10-4 which guides the occurrence of liquefaction. With tests on glass beads and sand from the Algiers bay, using a proper measuring system, we were able to arrive at a better resolution of this threshold and to the determination of its mechanical signification.

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Twice Dynamic Consolidation — An Unusual Application In Treating Liquefiable Saturated Sandy Loam Deposits, Yihui Qiu, Shuju Fan, Weiyuan Fan, Melyun Shi Mar 1991

Twice Dynamic Consolidation — An Unusual Application In Treating Liquefiable Saturated Sandy Loam Deposits, Yihui Qiu, Shuju Fan, Weiyuan Fan, Melyun Shi

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

More innovative methods of ground treatment have replaced traditional methods. Dynamic consolidation, for example, has been applied widespreadly in China. Presented in this paper is a case history of adopting the twice dynamic consolidation method to improve liquefiable saturated loesslike sandy loam deposit, since the site for the Aluminum Material Company which is located at the suburb of Talyuan, China, Is geotechnically adverse. In this project the effective depth of improvement increased significantly. Judged from the ln-situ investigation and laboratory triaxial shear test, the liquefaction potential was eliminated as predicted.

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Comparison Of Limit-State Seismic Earth Pressure Theories, D. G. Elms, R. Richards Jr. Mar 1991

Comparison Of Limit-State Seismic Earth Pressure Theories, D. G. Elms, R. Richards Jr.

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

The paper considers how, for the limit analysis approach to the seismic design of earth retaining structures, both the magnitude of soil force and the center of pressure vary with the type of displacement of the structure in translation or rotation. Two approaches are used. The first assumes that for a rotating wall the apparent internal friction angle of the backfill will vary for purely geometrical reasons. The second considers the effect of the peaked form of the stress-strain curve for a dense cohensionless soil. Both approaches show that, compared with a wall rotating about its base, the center of …

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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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Retaining Walls; Computation Of Seismically Induced Deformations, Sreenivas Alampalli, Ahmed-W. Elgamal Mar 1991

Retaining Walls; Computation Of Seismically Induced Deformations, Sreenivas Alampalli, Ahmed-W. Elgamal

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

A two dimensional (2D) dynamic wall-soil computational model is proposed. The model accounts for wall and soil resonance, nonlinear wall-backfill soil interaction, simultaneous wall base sliding and rotation, nonlinear soil properties and possible pore pressure buildup. A bending beam with a base yielding rotational spring and a base translational slide element represents the wall. A 2D shear beam represents the soil system. The wall and supporting soil interaction through a Winkler type nonlinear no-tension spring system. An elasto-plast1c path-dependent hysteretic model accounts for nonl1near so1l behavior and possible pore pressure buildup. The seismic response of a 15m high cantilever wall …

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Seismic Design Chart For Anchored Bulkheads, George Gazetas, Panos Dakoulas Mar 1991

Seismic Design Chart For Anchored Bulkheads, George Gazetas, Panos Dakoulas

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

Evaluation of numerous case histories reveals that the seismic performance of anchored sheet pile quaywalls depends primarily on the anchoring system. Current pseudo-static procedures often lead to deficient anchoring, whose excessive displacements or failure trigger excessive permanent seaward displacement at the top of the bulkhead, accompanied by cracking and settlement behind the anchor. The results of the case histories lead to a Seismic Design Chart to be used in conjunction with the pseudo static procedure. The Chart delineates between acceptable and unacceptable degrees of damage, depending on the values of two dimensionless parameters that are functions of the material and …

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A Comparison And Study On Artificial Boundaries: Conceptual Aspects, Zifa Wang Mar 1991

A Comparison And Study On Artificial Boundaries: Conceptual Aspects, Zifa Wang

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

The paper first analyzes the characteristics of various artificial boundaries (similarity and dissimilarity) and the derivation conditions of the boundaries. The problems involved in applying the artificial boundary in numerical computation and the solution to the problem are also discussed in the paper.

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Analysis Of Bridges For Seismic Hazard Mitigation In Kentucky, Yu Ouyang, Vincent P. Drnevich, David L. Allen Mar 1991

Analysis Of Bridges For Seismic Hazard Mitigation In Kentucky, Yu Ouyang, Vincent P. Drnevich, David L. Allen

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

The priority routes have been selected for Western Kentucky which shares the most hazardous New Madrid seismic zone. As the vital links on the priority routes, bridges need to be protected from collapse during earthquakes in order to maintain the access to the route for subsequent emergency traffic. In this paper, a support-loss type of bridge collapse due to earthquake induced abutment sliding is analyzed and corresponding criteria to this type of collapse is established. The analysis methods for existing bridge abutment are advanced. A computer program based on the methods is developed and applied to evaluate the potential earthquake …

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Dynamic Behavior Of Slender Structures On Their Prestressed Foundations, Phong M. Luong Mar 1991

Dynamic Behavior Of Slender Structures On Their Prestressed Foundations, Phong M. Luong

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

A non-destructive vibratory testing, using impulsive tension slacking has been devised for the quality and safety control of overhead line towers. Several structural control experiments have been conducted on four-legged towers resting on three types of foundations: concrete stepped or pedestal blocks, steel piles and prestressed foundations. Experimental results have given significant vibratory signatures in close connection with the geotechnical response characteristics of both such slender structures and their foundations. The control of foundation mechanical behavior may be very useful in cases of earthquake resistant construction and design. This paper presents some significant results of the test program.

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