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Liquefaction Potential Prediction By Multiple Stage Multifactorial Evaluation, Limin Zhang, Ting Hu Mar 1991

Liquefaction Potential Prediction By Multiple Stage Multifactorial Evaluation, Limin Zhang, Ting Hu

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

Factors affecting liquefaction are analyzed. Qualitative factors along with liquefaction itself are conceived to be of fuzziness the common methods cannot deal with. A new method – the Multiple-Stage Multifactorial Evaluation is introduced to evaluate the liquefaction potential of sand which can take into account not only the factors considered by the common methods but also these qualitative factors which otherwise cannot be considered by the explicit mathematic evaluation methods and can treat each factor according to its importance to liquefaction. Tests with the method show a higher correct evaluation rate over other methods. Conclusion is drawn about the liquefaction …

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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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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 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 During Two Moderate-Recent Earthquakes In India, Pramod N. Agrawal Mar 1991

Liquefaction During Two Moderate-Recent Earthquakes In India, Pramod N. Agrawal

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

The observations of liquefaction during the Cachar earthquake of N.E. India in December 31, 1984 (M=5.6) and the Great Nicobar earthquake of January 20, 1982 (M=6.3) have been reported. These observation, at short epicentral distances where duration of sustained motion was insufficient to postulate induced dynamic increase in pore water pressure, have been explained as quick-sand phenomena due to disturbance of soil structure under the influence of impulsive force associated with rupture at source. The proposed physical mechanism also explains well the bending of ceiling fan blades in Cachar earthquake and upthrow of objects during earthquakes in general. The discussion …

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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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Session 3: Opening Remarks, G. Castro Mar 1991

Session 3: Opening Remarks, G. Castro

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

No abstract provided.

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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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Sand Liquefaction With Initial Pore Pressures, Hong Xia Mar 1991

Sand Liquefaction With Initial Pore Pressures, Hong Xia

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

Cyclic triaxial tests are conducted on saturated sand samples with different values of initial pore pressures existed throughout the whole process of tests. It is found that the presence of such initial pore pressures (or static hydraulic pressures) tends to increase the liquefaction resistance of the sand samples. The effects of the degrees of saturation are also investigated by conducting another four sets of the cyclic triaxial tests on sand samples with different levels of saturation, since the degree of saturation is a very closely related factor which could be changed by the presence of the initial pore pressures. The …

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Semi-Analytical Iteration Algorithm Of Seismic Pore Pressure, Zhang Jianmin, Xie Dingyi Mar 1991

Semi-Analytical Iteration Algorithm Of Seismic Pore Pressure, Zhang Jianmin, Xie Dingyi

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

In this paper a semi-analytical iteration method for predicting the seismic pore-water pressure generation and dissipation in saturated sand layers is suggested. The fundamental formulae including three general analytical solutions under the condition of the 1-D, 2-D, and 3-D dissipation and the calculation principle are briefly presented, and then the suggested method is used in predicting the generation and dissipation of seismic pore water pressure in the 1-D saturated sand layers as an example. The suggested method provides the possibility to consider at a certain extent the change characteristics in permeability and volumetric strain of sand during the seismic action …

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Settlement Calculations Of Clay Layers Induced By Earthquake, Hiroshi Matsuda, Eiichi Hoshiyama, Sukeo Ōhara Mar 1991

Settlement Calculations Of Clay Layers Induced By Earthquake, Hiroshi Matsuda, Eiichi Hoshiyama, Sukeo Ōhara

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

A procedure to calculate the seismic settlement of clayey layers is developed based on the strain-controlled cyclic simple shear test results. By using this procedure the seismic ground settlements are estimated and also the results are compared with the observed ones. In the calculations, six types of accelerogram are used. As a result of estimations, following conclusions are obtained. (1) In the case of a horizontal soil layer of 5 m in height, the settlements are in the range from 3 to 6 cm for a maximum acceleration of about 340 gal. (2) In the case of clay deposits in …

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The Characteristics Of Residual Strength Of Silt Under Liquefaction Conditions, H.-C. Fei, F. Lu Mar 1991

The Characteristics Of Residual Strength Of Silt Under Liquefaction Conditions, H.-C. Fei, F. Lu

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

Silt soil is defined as a soil whose fine particles (D50 < 0.005mm) content is from 3% to 15%. The Tangshan earthquake of 1976 had a magnitude of 7.8 and caused the liquefaction of silt soil in large areas in Tianjin City. The seismic intensity at Tianjin was 8° in downtown. Currently the same criterion for initial liquefaction is applied to silt and sand, e.g., the development of pore pressure, u, equal to the effective confining pressure σ0'. However, in silt residual strength still exists because of cohesion due to the finest of the particles even when u = σ0' due to shaking. The authors employed a superimposed ring shear device to study the characteristics of residual shear strength of silts with different fine particle contents and with various pore pressure ratios, u/ σv' under both dynamic and static loads.

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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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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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Dynamic Earth Pressure Distribution Behind Retaining Walls, D. M. Dewaikar Mar 1991

Dynamic Earth Pressure Distribution Behind Retaining Walls, D. M. Dewaikar

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

The point of application of dynamic active thrust and its distribution are computed using the method of slices and criterion of maximization of overturning moment of the active thrust. The computations show that point of application of the dynamic thrust is significantly influenced by such factors as wall friction and acceleration coefficients. Horizontal accelerations coupled with positive vertical accelerations (acting downwards) have the effect of moving the point of application closer to the wall base. The combination of horizontal acceleration with negative vertical acceleration produces exactly the reverse effect and generates more overturning moments even though the magnitude of corresponding …

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Effective Stress Analysis Of A Sheet Pile Quaywall, Susumu Lai, Tomohiro Kameoka Mar 1991

Effective Stress Analysis Of A Sheet Pile Quaywall, Susumu Lai, Tomohiro Kameoka

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

In 1983, Nihonkai Chubu Earthquake of magnitude 7.7 hit northern part of Japan. The earthquake caused damage to quaywalls at Akita Port located about 100 km from the epicenter. The damage was associated with the liquefaction of backfill sand. In order to analyze the mechanism of the damage, soils are taken from the site for laboratory tests. The record of the earthquake motion is digitized. Based on these investigations, a two dimensional effective stress analysis is conducted. The model used in this study consists of a multiple virtual simple shear mechanisms oriented in arbitrary directions. The results of the effective …

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Seismic Design Of Rigid Underground Walls In New England, Cetin Soydemir Mar 1991

Seismic Design Of Rigid Underground Walls In New England, Cetin Soydemir

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

The Mononobe-Okabe equation is still widely used in design practice to estimate earthquake induced soil pressures against earth retaining structures without differentiation of the lateral yielding or non-yielding character of the structure. Where these structures are rigid and non-yielding because of structural restraints (e.g., basement walls, bridge abutments, underground transportation, hydraulic and sanitary structures) the use of Mononobe-Okabe equation would not be appropriate and would be generally unsafe. Alternate design recommendations are proposed, based on the results of recent analytical and experimental studies by other researchers, for a nominal design earthquake expected to be representative of the New England seismicity.

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Stability Of Fiber Reinforced Sand Retaining Walls, Masami Fukuoka, Kakuhiro Nakayama, Shun-Ichi Lhara, Kiyohiro Okedoi, Ken-Ichirou Ozaki Mar 1991

Stability Of Fiber Reinforced Sand Retaining Walls, Masami Fukuoka, Kakuhiro Nakayama, Shun-Ichi Lhara, Kiyohiro Okedoi, Ken-Ichirou Ozaki

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

A ten meter high retaining wall made by sands reinforced with continuous fibers was constructed in 1988. Thickness of the retaining wall was 1 mat the top and 2.5 m at the bottom, and the slope was 63° at the face and 71° at the back. Earth pressure acting on the wall, displacements of the face, settlements of the fill and acceleration of the retaining wall were measured. During the construction, around the third height of the wall was displaced 15 cm in a forward direction. At the time of an earthquake, the values of the maximum horizontal acceleration at …

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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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Anti-Seismic Reinforcement Of Pipelines In A Liquefied Ground, Takashi Akiyoshi, Kunihiko Fuchida Mar 1991

Anti-Seismic Reinforcement Of Pipelines In A Liquefied Ground, Takashi Akiyoshi, Kunihiko Fuchida

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

An anti-seismic structural-reinforcemental method for buried pipelines is presented and analytically investigated on the effectiveness for lateral flow of liquefied grounds during earthquakes. The proposed method of the reinforcement is to fix main pipelines with expansion joints to parallel auxiliary continuous pipes using iron-plates. Stiffness of liquefied soils is around pipes is represented as a coefficient of subgrade reaction between liquefied sand deposits and pipes, based on the experimental results. Analysis of the pipeline-soil spring systems is conducted using the modified transfer matrix method. Computations are performed with respect to the displacement, strain, stress, and rotational angle of joint of …

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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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Dynamic Compliance Of Pile Group Considering Nonlinear Behavior Around Piles, Koichi Kobayashi, Shintaro Yao, Nozomu Yoshida Mar 1991

Dynamic Compliance Of Pile Group Considering Nonlinear Behavior Around Piles, Koichi Kobayashi, Shintaro Yao, Nozomu Yoshida

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

Static and dynamic loading test of a foundation are carried out to obtain the behavior of a pile and a pile group. A conventional analysis based on the elastic wave theory are modified to obtain the complex rigidity of a pile group and are compared with the test results. It is shown that the analysis based on the conventional elastic wave theory are not enough to predict the dynamic behavior of piles since they do not take into account both the effect of slip and/or separation between the pile surface and the surrounding ground and the nonlinear behavior of the …

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Dynamic Response Of Flexible Foundations On Multilayered Medium, Wang Fuming Mar 1991

Dynamic Response Of Flexible Foundations On Multilayered Medium, Wang Fuming

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

The dynamic response of flexible strip-foundations placed on a viscoelastic multi-layered medium under conditions of plane strain and subjected to harmonic excitation is studied in this paper. A semi-analytic model is developed to determine the dynamic flexibility matrix of the medium, and the spline finite element method is employed to treat the foundation. The two methods are appropriately combined through equilibrium and compatibility considerations at the soil-foundation interface. Numerical results describing the influence of the non-homogeneity of the soil medium on the compliance are presented, and the effects of the relative stiffness Kr on the foundation response are briefly discussed.

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Earthquake Damages Influenced By Soil Conditions In Historical Buildings In Istanbul, Nafiz Çamlibel Mar 1991

Earthquake Damages Influenced By Soil Conditions In Historical Buildings In Istanbul, Nafiz Çamlibel

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

This paper is based on the study of the damages by earthquakes on the historical buildings constructed in Bysantine and Ottoman period and represents a preliminary approach to the problem of identifying the causes of these damages influenced by soil conditions. In this paper, some aspects of soil conditions and foundations systems are given related to the preservation of monument, especially the presentation is concentrated on the following topics: • An estimation of seismic area and on Design basis response spectra for historical buildings. • Geotechnical problems of the old city Istanbul. • Statistical aspects of masonry of Bysantine and …

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Earthquake Resistant Piles Reinforced With Ground Walls, Yoshiaki Nagataki, Hiroaki Senoo Mar 1991

Earthquake Resistant Piles Reinforced With Ground Walls, Yoshiaki Nagataki, Hiroaki Senoo

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

A method for reducing earthquake load acting on piles by means of ground walls installed around pile foundation is proposed. First, a shaking table test was carried out. Test specimens are 1/40 scale structural models, which consist of soil, piles and a building with or without ground walls. The pile head moment of the specimens with ground walls show only 60% of that of the specimens without the ground walls. An FEM analysis was carried out for both cases and the results were compared with the test results. The comparison showed a good agreement. Furthermore, a simplified calculation method is …

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Evaluation Of Seismic Soil-Structure Interaction (Ssi) By Different Approaches, Dan Mircea Ghiocel, Dan Ghiocel, Traian Mauna Mar 1991

Evaluation Of Seismic Soil-Structure Interaction (Ssi) By Different Approaches, Dan Mircea Ghiocel, Dan Ghiocel, Traian Mauna

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

The paper investigates the seismic SSI effects for rigid type structures. Structural response is computed by modal synthesis versus frequency response approach. The main aspects analysed are as follows: a) the seismic SSI effects on structural response; b) shortcomings in the current SSI computational procedure; c) seismic structure –soil-structure interaction (SSSI) effects on structural response of neighbouring heavy buildings. Two case studies are presented: a shearwell multistory building (SMB) on soft clay and a massive reactor building (RB). Seismic response quantities are accelerations, displacements, stresses, floor response spectra (FRS) and spectra amplification functions (SAF).

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