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Articles 131941 - 131970 of 136190

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Design Measures To Improve Performance Of Fill Dams Under Earthquake Loading, K. L. Logani Apr 1981

Design Measures To Improve Performance Of Fill Dams Under Earthquake Loading, K. L. Logani

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

Fill dams of height 50 meters or more are increasingly being planned, designed and constructed in highly seismic areas of the world. These dams incorporate various earthquake design measures. The design measures have been critically examined. Design guides with respect to free board, core base width, crest width, type and material of core and material of shells have been reviewed. Some examples of actual changes made in the design, for the seismicity of the region have been given (Table II). Finally, a table of pertinent data of over 50 high dams located in highly seismic areas of the world is …

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Dynamic Properties Of Embankment Dams, M. Öner, M. Erdik Apr 1981

Dynamic Properties Of Embankment Dams, M. Öner, M. Erdik

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

Forced vibration test result are presented for two large embankment dams. The results are compared with an approximately three dimensional finite element analysis. In addition a semi-empirical fundamental period expression is developed for use in the interpretation of the available natural period data. The period expression developed is based on the shear wedge solution for an inhomogeneous medium and takes the effect of the third dimension into account.

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Rockfill Dam Stability Problems In A Seismic Zone, A. Moroianu, V. Perlea Apr 1981

Rockfill Dam Stability Problems In A Seismic Zone, A. Moroianu, V. Perlea

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

In the close vicinity of the great shock, March 4, 1977, in Vrancea region, Romania, one of the biggest shocks felt recently in Europe, two rockfill dams 120 m and, respectively, 70 m high with clayey cores are being constructed. In the paper, some problems arised by the design of these dams from earthquake engineering point of view are presented.

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No Tension Approach To Define Failure Phenomena For Rockfill Dam Subjected To Earthquake Loading, K. G. Bhatia, R. Natarajan Apr 1981

No Tension Approach To Define Failure Phenomena For Rockfill Dam Subjected To Earthquake Loading, K. G. Bhatia, R. Natarajan

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

It has been observed that actual behavior of Rockfill dams during earthquake is much different than that obtained by elastic analysis. No tension approach has thus been developed to overcome the shortfalls of elastic analysis. Using no tension approach redistribution of stresses are obtained which help in defining the failure pattern of the dam' subjected to a given seismic acceleration or in other words the failure acceleration is obtained for a given dam subjected to earthquake forces. Various dam models having different upstream and downstream slopes are analyzed using finite element technique. The input earthquake motion has been considered as …

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Seismic Stability Indices Of Earth Structure, M. P. Singh Apr 1981

Seismic Stability Indices Of Earth Structure, M. P. Singh

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

Indices like cyclic damage and factor of safety are often used to quantify stability of soil systems subjected to earthquake loads. The methods used to obtain these indices are described; the relationship between cyclic damage and factor of safety through the concept of uniform stress equivalent time history is explored. For evaluation of a soil system design, the use of a direct approach is proposed. Evaluation of this approach by a simulation study is outlined. This approach, can use response spectra directly as seismic design input, and it provides an acceptable procedure for seismic stability prediction of soil systems.

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Embankment Design In Seismic Areas — Indian Practice, K. C. Thomas, S. N. Guru Rau, Bikram B. Raj Apr 1981

Embankment Design In Seismic Areas — Indian Practice, K. C. Thomas, S. N. Guru Rau, Bikram B. Raj

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

A number of river valley projects for the development of water and power resources, particularly in the Northern and North Eastern part of India, lie on the foothills of Himalayas which is seismically active. In the developmental activity of dam building, aseismic design of dam is therefore recognized and adopted. The paper presents the current Indian practice in the aseismic design of embankment dams with illustrations from studies carried out on some recent dams.

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Evaluation Of Seismic Stability Of Foundation Soils Under Revelstoke Earthfill Dam, K. S. Khilnani, P. M. Byrne Apr 1981

Evaluation Of Seismic Stability Of Foundation Soils Under Revelstoke Earthfill Dam, K. S. Khilnani, P. M. Byrne

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

The stability of the fine sands underlying the shells of the Revelstoke earthfill dam under earthquake shaking is discussed. The evaluation of liquefaction potential of the deposit was made from the field standard penetration resistance of the material. The dynamic analysis, made by a one-dimensional equivalent visco-elastic method, indicated that the sand under both the upstream and downstream shells had adequate liquefaction resistance and could be left in place. Adequate drainage of downstream fine sands was provided to further reduce its liquefaction potential.

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Earthquake-Resistant Design Of Earth Dams, H. Bolton Seed Apr 1981

Earthquake-Resistant Design Of Earth Dams, H. Bolton Seed

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

Lessons gained from observations of the field performance of earth darns during earthquakes are reviewed and used to illustrate the primary problems of concern. Defensive design measures which may be taken to mitigate the various hazards are reviewed and illustrated. Analytical approaches for evaluating seismic stability and the deformations of earth darns during earthquakes are discussed, together with recent developments which facilitate their implementation in special cases; situations which require careful consideration of special effects such as the three-dimensionality of the dam-valley system and pore pressure re-distribution following an earthquake are discussed and illustrated.

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Mechanism Of Surface Faulting And Its Seismic Effect, Zhong-Qi Wang, Shu-Tung Zhao, Zheng-Lu Huang Apr 1981

Mechanism Of Surface Faulting And Its Seismic Effect, Zhong-Qi Wang, Shu-Tung Zhao, Zheng-Lu Huang

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

The mechanism and reoccurrence rule of surface faulting have been analyzed based on macroscopic inspection and testing in the background of Tangshan earthquake 1976 and other events. It has been proved that such surface faulting bas only limited effect on surface structures nearby. And most of the surface ruptures in soil layer occurred in most earthquake zones are not the causative faults from focus up to the ground surface. Thus its seismic effect should be reestimated.

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Improvement Of Characteristics Of A Liquefiable Soil Deposit By Pile Driving Operations, M. Iyengar Apr 1981

Improvement Of Characteristics Of A Liquefiable Soil Deposit By Pile Driving Operations, M. Iyengar

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

Large scale failures of pile foundations driven in liquefiable soil deposits have been reported during the 1964 Alaska and Nighaata Earthquakes. Where the subsoil did not liquefy, the piles did not fail. These conclusions were the basis of selection of a proper pile type for the Bonoaigaon Complex wherein it was intended that the pile installation procedure shall also adequately densify the loose saturated sandy and silty subsoils prone to liquefaction during expected earthquakes at site. Studies were carried out to assess soil characteristics before and after piling and the resulting improvement in the subsoil. It is concluded that the …

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Wave Propagation At The Surface Of Clay Deposits Due To Vertical Impact, G. Lefebvre, M. Veber, J. G. Beliveau Apr 1981

Wave Propagation At The Surface Of Clay Deposits Due To Vertical Impact, G. Lefebvre, M. Veber, J. G. Beliveau

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

In a study of wave propagation at the surface of soft and sensitive clay deposits, particle velocities were measured at live sites of Champlain clay deposits in the province-of Quebec. Surface excitation was provided by the free fall of a mass and the measurements were obtained at different distances from the source at ground level and shallow depths. The major portion of the energy appears to be in the form of Rayleigh waves. Attention is focused on the effects of site parameters and in particular the depth of water table on the level of amplitude and the attenuation coefficient. As …

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Poor Water Pressure Rises During Earthquakes, K. Ishihara Apr 1981

Poor Water Pressure Rises During Earthquakes, K. Ishihara

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

A set of piezometers were embedded in sand deposits on a reclaimed island in Tokyo Bay and a seismograph was placed on the ground surface nearby in order to monitor insitu pore water pressures simultaneously with the horizontal accelerations during earthquakes. During the September 25, 1980 earthquake, the instruments registered increases of pore water pressures corresponding to 19% and 16 % of the effective confining pressure at depths of 6.0 m and 14.0 m, respectively. At the same time, a maximum horizontal acceleration of 95 gal was registered at the ground surface.

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Electrical Characterization Of Soil For In-Situ Measurement Of Liquefaction Potential, K. Arulanandan, S. J. Harvey, J. S. Chak Apr 1981

Electrical Characterization Of Soil For In-Situ Measurement Of Liquefaction Potential, K. Arulanandan, S. J. Harvey, J. S. Chak

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

A new method for characterizing the fundamental sand properties with electrical parameters is described. Correlations are established between the electrical parameters and relative density, Dr, cyclic stress ratio, τ/ σ'0, and the parameter K2max. An electrical probe, used to measure the electrical parameters in situ, is described. Field measurements, taken with the probe at one of the 1906 San Francisco earthquake sites, indicate that this is a viable alternative for the in situ evaluation of liquefaction potential.

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Campano-Lucano Earthquake, November 1980, Italy, Strong Motion Data Related To Local Site Conditions, A. Fels, A. Pugliese, F. Muzzi Apr 1981

Campano-Lucano Earthquake, November 1980, Italy, Strong Motion Data Related To Local Site Conditions, A. Fels, A. Pugliese, F. Muzzi

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

When the 23 November 1980 earthquake struck the south of Italy a network of strong motion recorders was in operation. The earthquake triggered 21 stations. The network is composed by 168 stations spread all over the country following statistical criterion, see Taccarino and Zaffiro, 1973. The paper presents the results of the records obtained at 6 of 21 stations together with the available geological information of the sites where the stations were located.

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Session 8: Final Comments By Moderator, K. Arulanandan Apr 1981

Session 8: Final Comments By Moderator, K. Arulanandan

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

No abstract provided.

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Seismic Response Of Subsurface Ground With Use Of Measured Underground Acceleration, T. Iwasaki, K. Kawashima, Y. Takagi Apr 1981

Seismic Response Of Subsurface Ground With Use Of Measured Underground Acceleration, T. Iwasaki, K. Kawashima, Y. Takagi

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

The seismic response of subsurface ground is investigated based on the measured underground acceleration records at three sites around the Tokyo Bay induced by several moderate earthquakes, Variations of maximum accelerations with respect to depth are described in both horizontal and vertical components, and Amplification of acceleration in underground is presented in terms of frequency response function, Correlations of the underground accelerations between theoretical calculation and actual records are also discussed.

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Different Magnitude-Epicentral Intensity Relations And Estimation Of Maximum Ground Acceleration, U. Chandra Apr 1981

Different Magnitude-Epicentral Intensity Relations And Estimation Of Maximum Ground Acceleration, U. Chandra

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

For an earthquake of magnitude 7.0 or larger, different published relations between magnitude, M, and epicentral intensity, I0, yield I0 values which may differ from each other by as much as one intensity unit or more. This implies an uncertainty of a factor of about 2 in the estimation of maximum ground acceleration. New empirical relations between M and I0 are derived using the revised estimates of I0 for several earthquakes. Suitability of some of the commonly used M - I0 relations for the estimation of maximum ground acceleration is examined by deriving acceleration-distance curves for …

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Analysis Of Stresses In Seismically Induced Shallow Slope Failures, Luis E. Vallejo, Lawrence M. Peszek Apr 1981

Analysis Of Stresses In Seismically Induced Shallow Slope Failures, Luis E. Vallejo, Lawrence M. Peszek

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

An analysis of the stresses induced by a combination of static and seismic forces on the failure surface of shallow soil slope instabilities is presented. The geometry of the failures, either shallow planar of finite length or shallow rotational, is taken into consideration in the analysis. The stress induced by a combination of the above forces is found to be greater for the planar than for the rotational ones. Therefore, at limit equilibrium conditions, the former will predominate. Field measurements of the geometry of shallow soil slope failures corroborate the theoretical findings.

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Discussion On "Zonation Of Central U.S. Earthquake Sources" By G. L. Hempen, Dinesh C. Gupta Apr 1981

Discussion On "Zonation Of Central U.S. Earthquake Sources" By G. L. Hempen, Dinesh C. Gupta

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

No abstract provided.

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Discussions, Umesh Chandra Apr 1981

Discussions, Umesh Chandra

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

No abstract provided.

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Program Of The Conference, Multiple Authors Apr 1981

Program Of The Conference, Multiple Authors

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

No abstract provided.

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Opening Remarks, Shamsher Prakash Apr 1981

Opening Remarks, Shamsher Prakash

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

No abstract provided.

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Opening Ceremonies - Images, Multiple Authors Apr 1981

Opening Ceremonies - Images, Multiple Authors

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

No abstract provided.

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Participants, Multiple Participants Apr 1981

Participants, Multiple Participants

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

No abstract provided.

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Shear Moduli And Damping Of Cohesive Soils Under Earthquake Loads, Wen-Yao Hu, Tian-Long Wang Apr 1981

Shear Moduli And Damping Of Cohesive Soils Under Earthquake Loads, Wen-Yao Hu, Tian-Long Wang

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

To investigate the dynamic properties of soils under earthquake loading conditions, a series of cyclic triaxial compression tests vas carried out on undisturbed saturated samples of cohesive soils from Tianjin. It has come to the conclusion that variation of damping ratio, as well as shear modulus, with strain amplitude may be expressed by an empirical formula. Its normalized form can be shown by a family of curves or a band zone with shrunken ends. New empirical equations used for evaluating elastic or initial shear modulus G0 and maximum shear stress τmax have been suggested. For the two parameters, …

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The Effects Of Time Dependent Stress-Path On The Plastic And Elastic Deformation Of Sand And Clay Soils Subjected To Dynamic Loading, G. Y. Baladi, T. Goitom, Rodney Lentz Apr 1981

The Effects Of Time Dependent Stress-Path On The Plastic And Elastic Deformation Of Sand And Clay Soils Subjected To Dynamic Loading, G. Y. Baladi, T. Goitom, Rodney Lentz

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

Cylindrical cyclic loading tests were used to study the effects of time dependent stress path on the plastic and elastic deformations of sand and clay soil samples. The test materials were obtained from the subgrade of existing highway pavements located throughout the state of Michigan. Approximately, 25 cylindrical soil samples (13.5 cm long, 5.5 cm in diameter) were tested under repeated loading conditions using different hydrostatic confining pressures and several time dependent stress-paths. In all tests, the first invariant of the stress tensor was cycled between two constant values and the first invariant of the stress deviator tensor was increased …

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Determination Of Dynamic Shear Modulus Of Soils From Static Strength, Y. S. Chae, W. C. Au, Y. C. Chiang Apr 1981

Determination Of Dynamic Shear Modulus Of Soils From Static Strength, Y. S. Chae, W. C. Au, Y. C. Chiang

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

A correlation study between the dynamic shear modulus obtained from the resonant column technique and the static strength obtained from the undrained triaxial compression test is described. The materials studied were a uniform sand, a non-active fine silty clay and a highly-active bentonite clay treated with additives to increase the range for static and dynamic shear strength of the soils. It is noted that a linear relationship exists between the dynamic shear modulus, except for those soil specimens having very low strength, independent of test parameters. Using linear regression analysis, empirical equations for predicting the maximum dynamic shear modulus from …

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Analysis Of Variation Of Poisson's Ratio With Depth Of Soil, Pan Fulan Apr 1981

Analysis Of Variation Of Poisson's Ratio With Depth Of Soil, Pan Fulan

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

Through field tests on clay, soft soil, sand soil, and cl93 loam etc., we find: l) Propagating velocity of elastic wave of homogeneous soil is not a constant, but a function of depth. 2) Poisson's ratio is not a constant either. It increases with the increase of depth. 3)The ratio of a lateral compressive stress to vertical compressive stress acted upon an element at different depth is not a constant either. With the increase of depth, the lateral compressive stress tends to be equal to the vertical compressive stress step by step. Test results of four types of soil are …

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Dynamic Shear Modulus Of Soft Silt, H. Y. Fang, R. C. Chaney, N. S. Pandit Apr 1981

Dynamic Shear Modulus Of Soft Silt, H. Y. Fang, R. C. Chaney, N. S. Pandit

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

This paper presents the geotechnical properties of soft silt obtained from the Greater Shanghai Region of the People's Republic of China. Fundamental correlations of shear modulus, damping ratio, shear stress, shear strain with varying consolidation pressures are determined in the laboratory by cyclic simple shear tests. A comparison is made between laboratory test results, in situ cross-hole test results and the building code data proposed by the Shanghai Municipal Bureau. Finally, a comparison of the laboratory data on Shanghai silt with other published data on sands and clays is presented and discussed.

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Strain-Rate Dependent Shear Modulus Of San Francisco Bay Mud, William M. Isenhower, Kenneth H. Stokoe Apr 1981

Strain-Rate Dependent Shear Modulus Of San Francisco Bay Mud, William M. Isenhower, Kenneth H. Stokoe

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

The effects of shearing strain amplitude and shearing strain rate on the shear modulus of normally consolidated specimens of San Francisco Bay Mud were studied with a specially constructed torsional shear/resonant column device. Torsional shear measurements were performed at excitation frequencies of 0.03, 0.1, 0.3, and 1.0 Hz and were followed by a resonant column measurement at the same strain amplitude. This testing sequence was conducted at constant values of shearing strain amplitude over the range from 0.001 to 0.1 percent. From these measurements the dependency of shear modulus on shearing strain rate and amplitude was studied. Shear modulus was …

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