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Downhole Seismic Cone Analysis Using Digital Signal Processing, R. G. Campanella, W. P. Stewart

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

In-situ measurement of the dynamic characteristics of surficial soils is becoming more common in geotechnical practice for prediction of ground surface motions from earthquake excitation and to evaluate foundations for vibrating equipment. Techniques for these measurements have been under development at the University Of British Columbia (U.B.C.) since 1980. The paper discusses many practical considerations with respect to equipment (sources, receivers, trigger, etc.) and procedures that can affect the interpretation and analysis of seismic cone results. A brief review is given of the cross-over method as used at UBC to determine interval shear velocity travel times from downhole seismic cone …

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 …

GMax From Pressuremeter Tests: Theory; Chamber Tests; And Field Measurements, Peter M. Byrne, Francisco Salgado, J. A. Howie

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

A method of analysis to predict the in situ maximum shear modulus G_max,0 from self-boring pressuremeter unload tests is presented. The method considers both the stress and void ratio changes induced by pressuremeter loading and the nonlinear stress-strain response upon unloading. The results are presented in the form of a chart that allows G_max,0 to be determined from the equivalent elastic unload modulus, G*, for a wide range of loading and unloading conditions. The analysis procedure is checked with chamber tests and field data and the results are found to be in good agreement provided factors to account …

Lnsitu Measurement Of Damping Of Soils, W. P. Stewart, R. G. Campanella

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

The Seismic Cone Penetration Test (SCPT) has been shown to give reasonable results for insitu measurements of shear wave velocity, and this paper extends this work to include measurements of damping. The relevant equations of motion are described, factors affecting amplitude decay are discussed, and the nature of damping is summarized. Consideration is given to some of the practical aspects of pre-processing of signals. Three methods of damping calculation are presented. The first two, attenuation coefficient and modified SHAKE methods, require the application of amplitude corrections, which is not straight-forward, give variable results, and indicate negative damping in a clayey …

Lumped Parameters In Permanent Displacement, H. V. Phuong Truong

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

New dynamic spring and damping values, which are dependent on the frequency, have been introduced into calculations of horizontal permanent displacement. The new dynamic damping value, which is inversely proportional to the circular frequency, has the same form as the material damping, while the new value of stiffness increases with increase in circular frequency. Similar methods can be used to obtain new dynamic spring and damping values for other modes of vibrations such as vertical, rocking and torsional. An analytical treatment of the coupled rocking and sliding modes is presented which considers horizontal and vertical Coulomb friction forces, two-layered soil …

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.

Modeling The Monotonic And Cyclic Viscoplastic Soil Behavior, Ronaldo I. Borja

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

We describe a class of viscoplastic constitutive models capable of simulating the monotonic and cyclic rate-dependent soil behavior. These models are developed by enriching their inviscid counterparts with a viscous character to model the irreversible deformation that develops with time. The viscoplastic strain rate is of the Duvaut-Lions type whose magnitude increases with the distance of the stress point from its projection onto the inviscid solution. With appropriate choice of an inviscid elasto-plastic soil model, one can generate quasipreconsolidation effects during creep and account for the influence of frequency on the shape and width of hysteresis loops formed during cyclic …

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 …

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 …

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.

General Report Session 1: Static And Dynamic Soil Parameters And Constitutive Relations Of Soils, Peter M. Byrne, Li Yan

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

The soil parameters that are commonly of interest in dealing with earthquake and soil dynamics problems are:

1) The maximum shear modulus G₀, or the shear wave velocity, V_s.

2) The variation of secant shear modulus with shear strain level, G/G₀ vs γ.

3) Equivalent viscous damping as a function of strain.

4) Other parameters such as, dilatometer modulus, normalized SPT or CPT value, state parameters, formation factor.

In terms of constitutive relations the following models have been used:

1) Linear elastic (total stress) - appropriate at very small strains < 10^-3%.

2) Equivalent linear …

Stiffness And Damping Of Sands In Torsion Shear, Supot Teachavorasinskun, Hiroyuki Kato, Satoru Shibuya, Noriyuki Horii, Fumio Tatsuoka

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

A laboratory investigation was carried out into stiffness and damping of sands as sheared in a torsional shear apparatus. In the drained monotonic and cyclic loading tests, a particular care was taken of the small strain measurements in which the secant stiffness was measured over a wide range of shear strain from about 10^-6 to 10^-2. Despite the marked differences in the grain size and the sample preparation method among the sands, a fairly good coincidence of the secant stiffness was seen, in common, in the range of shear strain less than about 1 x 10^{-5 …}

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.

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.

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%.

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.

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.

An Innovative Dynamic Test Method For Piles, M. C. Janes, R. C. Horvath, P. D. Bermingham

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

The system described involves using solid propellant fuels to accelerate a reaction mass of the test pile. The force required to accelerate the reaction mass upwards acts equally downward on the pile. Very high forces be may applied to the pile in a controlled, linearly increasing manner. The duration of the applied load is approximately 100 milliseconds. This rate of loading is slow enough to allow the pile and soil to react together as a composite rigid body. The effects combine to produce pile and soil response no longer dominated by the transfer of force via stress pulse (as with …

Centrifugal Modeling Of A Pile Under Vertical Random Excitation, Lary R. Lenke, Hon-Kim Ko, Ronald Y. S. Pak

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

Data from the experimental modeling of a pile in a geotechnical centrifuge are compared with analytical results. The model pile was subjected to vertical random excitation with subsequent determination of the compliance function in the frequency domain. This compliance function was found to be consistent with theory. An absorbing boundary was used to minimize reflected wave energy from the centrifuge container boundaries.

Session 2: Closing Remarks, C. K. Shen

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

No abstract provided.

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 …

Session 2: Discussions And Replies, Multiple Authors

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

No abstract provided.

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 …

Laboratory Tests On Embedded Reactor Building On Soft Ground, Ltaru Kurosawa, Shohara Ryoichi, Kinji Akino, Masanori Izumi

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

Model tests using shaking table and impulse hummer were performed to confirm analysis tools currently used in Japan for the seismic design of a reactor building embedded in soft ground. The models are made of a silicone rubber ground and an aluminum building. Embedment depths of the foundation are varied. Comparison between test results and analytical results is discussed in terms of impedance functions, foundation input motions and structure responses.

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 …

Large-Scale Model Forced-Vibration Test Comparison Of Test Results On Hard And Soft Ground, Takeshi Fujimori, Tomohiko Tsunoda, Kinji Akino, Masanori Izumi

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

Forced-Vibration tests were performed on two large-scale same models constructed on soft and hard ground in order to investigate the effect of the hardness and the stratification of the supporting ground on the vibration characteristics of simulated reactor buildings. The soft ground is almost stratification ground, and the hard ground is almost uniform ground. The test models are RC rigid frame structure with shear walls. In the tests, sinusoidal wave excitation was applied by the excitor. The vibration characteristics of the test models, earth pressure at the bottom of the base mat and the vibration characteristics of the surrounding ground …

Liquefaction Tests By A Laminar Box In A Centrifuge, Kichio Suzuki, Ryouichi Babasaki, Yoshio Suzuki

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

A new laminar box constructed with aluminum frames of 24mm wide and 10mm thick for model shaking tests on liquefaction phenomenon of soft saturated sandy soil in centrifugal gravity field was manufactured. The box was designed to develop shear distortion in the soil unimpeded by a rigid-type container. Liquefaction tests were performed on horizontally laid soft saturated sand and obtained the same results as Tokimatsu and Yoshimi 1983.

Prediction Of Fatigue Cracking And Rutting In Asphalt Pavements By Small-Scale Centrifuge Models, M. Hossien Roghani, V. P. Drnevich, Y. H. Huang

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

This paper presents a summary of a study to investigate the feasibility of predicting fatigue cracking and rutting in full depth asphalt pavements by centrifuge modeling. This is accomplished by constructing a small-scale centrifuge model and measuring directly the resilient tensile strains at the bottom of asphalt layer and the accumulated permanent on the pavement surface under repeated loads. The purpose of using a centrifuge is to insure that the stresses and strains due to self-weight are the same in the small-scale model as in the prototype pavement. Model pavements in two different scales of 1:10 and 1:20 were constructed, …

Shaking Table Tests On Permanent Ground Displacement Due To Liquefaction, Susumu Yasuda, Hiroyoshi Kiku, Hideo Nagase

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

To study the mechanism of permanent ground displacement due to liquefaction, shaking table tests were conducted. Moreover, vane tests and cyclic torsional shear tests were carried out to measure the rate of decrease of the elastic modulus and the shear strength due to liquefaction. Based on these test results, the authors proposed a simplified procedure for the prediction of permanent ground displacement. Measures to counter permanent ground displacement were also discussed based on the analysis.

Test On Behavior Of Pile Foundation In Liquefiable Soils, H. S. Liu, K. J. Chen

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

A series of shaking table tests were conducted to clarify the compaction effects of pile driving on sandy soils, and to investigate the failure mechanism of pile foundation in liquefiable soils. The tests showed that the soil in piled zone was densified so greatly that it became non-liquefiable after pile driving. The pore pressure ratios within this zone were far lower than unit. The settlements of pile foundation were mainly caused by the movement of soil beneath pile tips to the liquefied zone which was outside the piled zone. The failure patterns of pile foundation were rather like the Meryerhoff's …