Swell pressure prediction by suction methods     

Yusuf Erzin  Orhan Erol 《Engineering Geology》2007,92(3-4):133-145

Soil suction is the most relevant soil parameter for characterization of the swell behavior. An attempt was made to predict swell pressures from soil suction measurements. In this study, Na-bentonite was mixed with kaolinite in the ratios of 5, 10, 15, 20 and 25% of dry kaolinite weight to obtain soils in a wide range of plasticity indices (i.e. 30, 50, 68, 84 and 97%). Suction measurements using thermocouple psychrometer technique were made on statically compacted specimens. The dependence of soil suction on water content, dry density and bentonite content was examined. Soil suction was correlated to the soil properties, namely, water content, plasticity index, dry density, cation exchange capacity and specific surface area using multiple regression analyses. The correlations revealed a simple regression equation for a quick prediction of soil suctions from easily determined soil properties. In order to investigate soil suction versus swell pressure behavior, the results of standard constant volume swell tests (ASTM, 1990) performed on statically compacted samples of these clay mixtures were used. A linear relationship was established between the logarithm soil suction and the swell pressure. It was also found that an experimental relationship which would directly relate the initial soil suction to the swell pressure can be established.  相似文献   

Seismic energy dissipation in deteriorating systems through low‐cycle fatigue     

Altu Erberik  Haluk Sucuolu 《地震工程与结构动力学》2004,33(1):49-67

Energy dissipation characteristics of structural members which exhibit both strength and stiffness deterioration under imposed displacement reversals are investigated. In the experimental part, 17 reinforced concrete beam specimens were tested under constant and variable amplitude inelastic displacement cycles. The constant‐amplitude tests were employed to determine the low‐cycle fatigue behaviour of specimens where the imposed displacement amplitude was the major variable. A two‐parameter fatigue model was developed in order to express the variation of dissipated energy with the number of displacement cycles. This model was then used to predict the energy dissipation of test specimens subjected to variable‐amplitude displacement cycles simulating severe seismic excitations. It has been demonstrated that the remaining energy dissipation capacity in a forthcoming displacement cycle is dependent on the energy dissipated along the completed displacement path. Moreover, it is observed that total energy dissipation is dependent on the length of the displacement path. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Energy‐based hysteresis and damage models for deteriorating systems     

Haluk Sucuolu  Altu Erberik 《地震工程与结构动力学》2004,33(1):69-88

The low‐cycle fatigue model presented in the companion paper is employed for developing hysteresis and damage models for deteriorating systems. The hysteresis model performs strength reduction at a current displacement cycle by evaluating the loss in the energy dissipation capacity along the completed displacement path. Hence it is completely memory dependent. Pinching is accounted for implicitly by a reduced energy dissipation capacity in a displacement cycle. The model predicts the experimental results obtained from variable‐amplitude tests reasonably well. Response analysis under earthquake excitations reveals that both the maximum displacements and the number of large‐amplitude displacement response cycles increase significantly with the reduction in energy dissipation capacity, resulting in higher damage. Damage is defined as the deterioration in the effective stiffness of a displacement cycle, which is in turn related to the reduction in the energy dissipation capacity. A simple damage function is developed accordingly, consisting of displacement and fatigue components. It is observed that the fatigue component of damage is more significant than the displacement component for deteriorating systems under ground motions with significant effective durations. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Engineering characteristics of the near-field strong motions from the 1999 Kocaeli and Düzce Earthquakes in Turkey     

Haluk Sucuoğlu 《Journal of Seismology》2002,6(3):347-355

The purpose of this paper is to summarize the strong motion data from thenearest stations to the fault ruptures of the August 17, 1999 Kocaeli andNovember 12, 1999 Düzce earthquakes and to document informationthat will be significant for its interpretation. Significant engineeringcharacteristics of the near-field strong motions are discussed, with particularemphasis on the site conditions, rupture directivity effects and transversecomponent orientations relative to the fault. In the course of this study,the most significant strong motion stations and adjacent parts of the faultare visited. All locations are verified using a hand-held GPS receiver. Thusinstrument housing characteristics, preliminary impression on siteconditions, and relatively precise relationship of the stations to the nearestfaulting can be reported.  相似文献   

Guest editorial     

Polat Gülkan  Haluk Eyidoğan 《Journal of Seismology》2002,6(3):285-286

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Earthquake ground motion characteristics and seismic energy dissipation     

Haluk Sucuolu  Alphan Nurtu 《地震工程与结构动力学》1995,24(9):1195-1213

The sensitivity of seismic energy dissipation to ground motion and system characteristics is assessed. It is found that peak ground acceleration, peak ground velocity to acceleration (V/A), dominant period of ground excitation and effective response duration are closely correlated with the energy dissipated by a SDOF system. Ductility ratio and damping ratio have no significant influence on the energy dissipation. An energy dissipation index is proposed for measuring the damage potential of earthquake ground motion records which includes the effects of basic excitation and response characteristics contributing to the seismic energy dissipation. The proposed index is compared with several intensity measures for the set of 94 ground motion records considered in the study.  相似文献   

Vibration analysis of stepped-pipe strings for mining from deep-sea floors     

Haluk Erol   《Ocean Engineering》2005,32(1):37-55

The present study addresses essentially to the investigation of the longitudinal vibrations of a stepped-pipe string for mining from deep-sea floors. The stepped-pipe string, consisting of four parts having different physical properties in each pipe string segment, is assumed to have two pump modules and a buffer, each of which is equipped with a vibration absorber. Moreover, the pipe string is subjected to external viscous damping because of the surrounding medium. A theoretical analysis has been made for a simplified model of the system, in which it is assumed that both the pump modules and buffer can be considered as concentrated masses, the fluid inside of the pipe string vibrates together with the string, and that the flexible pipe does not affect the vibration of the pipe string. Furthermore, absorbers are modeled as concentrated masses, each of which is attached to pump modules and the buffer by springs and dampers. Applying the method of separation of variables, exact analytical solutions for damped free and forced responses of the system subjected to heave motion of the mining ship are determined with and without absorbers, in which overdamped and underdamped modes are determined and studied separately too. It is important to note that the solutions obtained are expressed in terms of parameters characterizing the physical properties of the system under consideration. Numerical applications show that the attachment of convenient vibration absorbers causes the longitudinal displacements at the certain locations to decrease to very small values, where the vibration absorbers are adjusted to the excitation frequency.  相似文献   

The sources of metal contents in the shelf sediments from the Marmara Sea, Turkey     

Oya Algan  Nuray Balkıs  M. Namık Çağatay  Erol Sarı 《Environmental Geology》2004,46(6-7):932-950

The shelf area is the largest morphological unit of the Marmara Sea and is subjected to increasing population, urbanization, and industrial activities. Metal contents (Al, Fe, Mn, Cu, Pb, Zn, Ni, Cr, Co and Hg) of the surface sediments from the shelf areas of the Marmara Sea generally do not indicate shelf-wide pollution. The variability of the metal contents of the shelf sediments is mainly governed by the geochemical differences in the northern and southern hinterlands. Northern shelf sediments contain lower values compared to those of the southern shelf, where higher Ni, Cr, Pb, Cu and Zn are derived from the rock formations and mineralized zones. However, besides from the natural high background in the southern shelf, some anthropogenic influences are evident from EF values of Pb, Zn and Cu, and also from their high mobility in the semi-isolated bay sediments. Anthropogenic influences are found to be limited at the confluence of Istanbul Strait in the northern shelf. However, suspended sediments along the shallow parts of the northern shelf were found to be enriched in Pb and Hg and to a lesser degree in Zn, reflecting anthropogenic inputs from Istanbul Metropolitan and possibly from the Black Sea via the Istanbul Strait.  相似文献   

Source parameters of large earthquakes in the East Anatolian Fault Zone (Turkey)   总被引：3，自引：0，他引：3  

Tuncay Taymaz  Haluk Eyidoan  James Jackson 《Geophysical Journal International》1991,106(3):537-550

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The 1 October 1995 Dinar earthquake, SW Turkey     

Haluk Eyidoan  Aykut Barka 《地学学报》1996,8(5):479-485

The Dinar earthquake (M_s= 6.1, USGS-PDE) of 1 October 1995 occurred on the NWSE-trending Dinar Fault. The earthquake is associated with a 10-km-long surface rupture with predominantly normal faulting. The mainshock was preceded by a series of foreshocks that started 6 days before the mainshock and included two M_d = 4.5 events. The mainshock source mechanism derived from the inversion of broad-band P waves revealed that two sub-events occurred on a NW-SE trending normal fault with a small strike-slip component. According to the source model estimated in this study, the first rupture started at a depth of about 8 km and reached to a depth of about 12 km propagating north-west. The total seismic moment found from the inversion of P waveforms is 2.0 times 10 ¹⁸ Nm. The seismic moment of the second sub-event was about four times larger than the first one. Field observations, GPS measurements and slip vector obtained from the inversion of broad-band P waveforms suggest that the NW-SE trending Dinar Fault is due to the internal deformation of SW Anatolia moving south-westwards.  相似文献