Significant duration is a key descriptor of shaking that governs the number of cycles in effective stress analyses used in liquefaction triggering and other dynamic geotechnical assessments. Because rock stations are commonly treated as reference conditions for seismic input selection, a rock-site-focused duration model can reduce ambiguity introduced by site amplification and basin effects. This study explores data-driven relationships between significant duration (D5 ‐ 95) and commonly used ground-motion metrics using strong-motion recordings from 59 stations located on rock units (NHRP class B, Vs, 30 ≥ 760 m/s) in Türkiye. Artificial neural networks (ANNs) were developed in two stages: a baseline model using moment magnitude (Mw) and rupture distance (Rrup) to support rapid, scenario-based applications, and an enhanced model incorporating Arias intensity (IA), cumulative absolute velocity (CAV), peak ground acceleration (PGA), and peak ground velocity (PGV) to capture record-specific shaking characteristics. The ANN framework successfully reproduces the expected increase of D5, 95 with Rrup and highlights region-dependent behavior at larger distances. Adding intensity- and velocity-based predictors improves predictive skill, and sensitivity analysis indicates that CAV exerts the strongest influence on D5 ‐ 95 among the examined motion parameters. The proposed models provide practical tools for selecting and scaling rock-site inputs and for incorporating duration effects into liquefaction-oriented and site-response workflows.

The significant duration (D5,95) is an important parameter in geotechnical earthquake engineering, directly influencing the number of cycles in effective stress analyses and playing a pivotal role in evaluating soil liquefaction potential. Liquefaction susceptibility is dependent on the number of cycles, which is inherently related to the duration of the earthquake and the response of the soil. In dynamic site response analyses, ground motions recorded on rock sites are essential because they serve as the excitation input, minimizing site-specific effects such as amplification or valley influences. Consequently, the significant duration of these rock-based ground motions becomes a fundamental parameter in evaluating liquefaction and selecting ground motions for site response analyses. However, existing duration models are predominantly regression-based ground motion prediction equation (GMPE) formulations calibrated on mixed site conditions, and predictors trained exclusively on rock-station recordings using artificial neural networks (ANNs) remain scarce. In this regard, the relationships among significant duration (D5,95) and key seismological and intensity measures were investigated within an ANN framework using a rock-site dataset compiled from T & uuml;rkiye Strong Ground Motion Database (1208 records from 143 earthquakes with moment magnitudes (Mw) >= 4.5) recorded at 59 stations established on rock units (NEHRP class B or harder rock, Vs,30 >= 760 m/s) (AFAD, 2023). Two complementary models were developed: a baseline ANN using (Mw, rupture distance (Rrup), and Vs,30)and an enhanced ANN additionally incorporating peak ground acceleration (PGA) and cumulative absolute velocity (CAV). The enhanced model yields improved predictive performance and tighter residual dispersion relative to the baseline model. Sensitivity analysis indicates that CAV is the most influential predictor of D5,95, followed by Rrup and PGA, highlighting the dominant role of cumulative/energy-related measures under rock-reference conditions. These results provide a practical two-tier framework for estimating rock-site significant duration in T & uuml;rkiye, supporting duration-aware motion selection and nonlinear geotechnical analyses.

This study presents an assessment of geotechnical damage observed in Gölbaşı District in the Adıyaman Province after the southeastern Türkiye earthquake sequence on February 6, 2023. Preliminary reconnaissance indicated the presence of soil ejecta with a plasticity index typically higher than nine, questioning the role of flow liquefaction during these events. Detailed observations revealed various types of damage, including major ground settlements up to 60 cm near several buildings, substantial cracks in highway sections, undulations in railway tracks, and observable fissures on roads and pavements. Given the predominance of plastic soils underlying the city center and the malfunction of strong motion station 0208 in Gölbaşı, the underlying cause of such widespread damage remains a complex phenomenon. Therefore, to unravel the principal cause of damage, this study conducted a detailed analysis of the geotechnical properties of soils. An extensive laboratory testing program, in combination with original interpretation of in-situ tests performed before and after the earthquake sequence enabled accurate characterization of properties of the underlying soil profile. The primary factors contributing to the extensive geotechnical damage in Gölbaşı are identified along with the main failure mechanisms, focusing on the role of cyclic softening of the predominantly fine-grained soils rather than flow liquefaction.

This paper investigates the anisotropic characteristics of Champlain marine clay soil using a combination of laboratory techniques. A modified oedometer cell with a piezoelectric ring actuator technique was used to measure shear wave velocity during consolidation stages. The axisymmetric design of the oedometer allowed for the determination of shear wave velocity in both the vertical and horizontal planes. The preliminary findings reveal that the sensitive marine clay is inherently anisotropic, with lower preconsolidation pressure for horizontally consolidated specimens and faster propagation of shear waves in the plane parallel to the bedding layer. High-precision strain gauges integrated into the consolidation ring were used to evaluate horizontal stress during the one-dimensional consolidation test. The ability to determine mean effective stress enables the normalization of shear wave velocities using this stress, providing more coherent empirical correlations in terms of shear wave velocity. Scanning electron microscopy was used to examine the microstructure of clay specimens, providing qualitative and quantitative insight into the restructuring and reorientation of clay platelets under consolidation stress. The consistency of the results through both micro and macro-scale analyses confirms the reliability of the experimental approach, highlighting its potential for future studies on the anisotropy of Champlain marine clay fabrics.

The cyclic direct simple shear (CDSS) test has been widely used for dynamic analysis, including soil liquefaction. CDSS enables the replication of shear wave propagation and considers more representative stress conditions during earthquakes. Several studies have investigated the drawbacks of CDSS, including the prominent artificial pressure jump (Ru* jump) produced in the first few cycles during constant-volume tests, as demonstrated in the pioneer works of Prevost and H & oslash;eg (1976) [37]. However, the effect of this pressure jump on the overall CDSS results, including the number of cycles to produce liquefaction or cyclic mobility, has not yet been investigated experimentally. Therefore, this study investigated this aspect using a series of strain- and stress-controlled fully undrained triaxial simple shear (TxSS) and constant-volume CDSS tests. Strain-controlled test results were used to establish relationships between dissipated energy and Ru to examine the difference between the fully undrained and constant-volume tests conducted on the same basis. The results show that the artificial Ru* leads to the overestimation of the Ru values and underestimation of the cyclic resistance. However, consistency between the CDSS and TxSS results was achieved after correcting the Ru* jump error. The agreement between the experimental and numerical results confirms the efficiency of the stain-based energy concept to improve the cyclic CDSS test results.

Pavement materials like hot mix asphalt (HMA) and cold recycled mixes (CRMs) are typically considered isotropic. This study evaluates the anisotropy of a cold in-place recycled (CIR) material using the shear wave velocity (Vs) parameter. The piezoelectric ring actuator technique (P-RAT) is utilized to assess the Vs parameter in three directions in CIR slabs. Similarly, the ultrasonic pulse velocity (UPV) technique is employed to measure P-wave velocities. Both methods evaluate mechanical properties in multiple directions. Complex modulus tests are conducted to link velocities results to |E*| modulus. Finally, computed tomography (CT) scans are performed on the specimens in order to evaluate anisotropy resulting from aggregate alignment. The Vs obtained using P-RAT and the Vp from UPV indicate anisotropy, as the wave velocities differ across the three directions. Differences range from 0.6 to 11.6% in Vs, influenced by measurement location. UPV results are analysed in relation to the |E*| modulus master curves, demonstrating that the first peak arrival time for the P-wave corresponds with the master curve. CT scan analysis reveals that the aggregates tend to be more aligned in the direction of the compacting wheel’s displacement, which also highlights anisotropy.

Shear wave velocity (V s ) plays a central role in soil dynamics and is widely used in seismic site classification, liquefaction assessment, and earthquake stability analysis. One of its distinguishing features is that it directly relates to small-strain shear modulus (G = ρVs 2 ), making it the only mechanical property that can be consistently measured in both field and laboratory settings. Field measurements of V s are particularly valuable because they capture soil stiffness in its natural, undisturbed state, offering insight into in-situ density conditions. Despite its relevance, V s remains underutilized in geotechnical practice. Given its sensitivity to factors such as soil density, stress conditions, and preloading history, accurate measurement of V s can provide a robust and reliable geotechnical parameter. Several studies have reported that shear wave velocities obtained from laboratory tests tend to be lower than those measured in the field. This discrepancy is commonly attributed to disturbances caused by the sample extraction process. Such disturbance effects are not limited to Vs measurements; they also impact other geotechnical properties assessed in the lab, such as undrained shear strength and pre-consolidation pressure. To address this issue, it is essential not only to work with high-quality clay specimens but also to develop strategies for quantifying and correcting sampling-induced alterations. This study introduces a novel method to evaluate the extent of disturbance resulting from sampling and specimen handling. It further proposes a correction approach for laboratory-derived stiffness parameters. These corrected values are then benchmarked against in-situ measurements obtained under undisturbed conditions. Finally, the adjusted laboratory data are integrated to enhance the interpretation of field measurements in stres-strain analyses.

The characterization of cold recycled bituminous materials (CRMs) at a very young age, shortly after compaction, is inherently challenging due to the nature of the material. The granular aspect of CRM at this stage and its high-water content render the use of conventional mechanical techniques impractical. Following previous work, the use of a nondestructive technique based on the frequency analysis of mechanical elastic shear waves, piezoelectric ring actuator technique (P-RAT), has enabled assessment of the behavior of cold in-place recycled material treated with bitumen emulsion from 10 min after compaction to 30 days of curing. Emphasis on shear wave velocity (V-s) measurements during the early age confirmed the rapid stiffening of the mix along with the departure of water present in the mix. A 6 degrees C drop of the surface temperature is observed along with this rapid increase of V-s and water loss. The initial and final V-s values range from 287 to 330 m s(-1) and from 461 to 578 m s(-1), respectively. To assess the capabilities of P-RAT, specimens with different void contents were tested, mainly 12, 15, and 17 %. It was observed that in each tested specimens, a similar behavior was exhibited during the first few hours of curing. Based on these observations, hypotheses are put forth regarding the phenomena governing the increase in stiffness during this period. Finally, the influence of the compaction of the specimens on the V-s values is consistent and comparable with the information available in the literature for such CRM.

For reliable seismic design of earth-retaining structures, it is critical to accurately assess the magnitude and distribution of dynamic earth pressures. Over the years, numerous experimental and numerical studies have sought to clarify the complex soil–structure interactions in backfill–wall systems under seismic loads. This article expands on an earlier review by the authors of analytical and field performance studies addressing the seismic behavior of retaining walls. Despite extensive research, there is still no consensus on a standardized seismic evaluation method or on the necessity of including seismic loads in the design of retaining structures. This review critically examines notable experimental and numerical findings on dynamic lateral earth pressure, highlighting that the current design practices cannot be generally applied to all types of retaining structures. More importantly, these practices often rely on experimental data extrapolated beyond their original applicability.

Construction activities, such as blasting, pile driving, and other heavy operations, near sensitive clay deposits can disturb and soften the soil structure, causing both transient and permanent deformations, thereby reducing the soil’s shear strength. These disturbances can impact clay slopes and adjacent structures, threatening their stability. In practice, vibration monitoring is based on the Peak Particle Velocity (PPV) concept, which was initially developed for rock blasting and is used to control damage to structures, rock slopes, and clay slopes, thereby preventing failures triggered by vibrations from various construction activities. However, current standards fail to provide acceptable PPV thresholds for clay deposits and slopes as these thresholds were originally adopted from rock surface measurements during blasting; additionally, applying the same threshold to different soil types is impractical due to their unique characteristics. Each type of clay has a critical shear strain (γt), below which negligible or no pore pressure and strength degradation occur. Therefore, this paper aims to develop a new practical approach to control vibration and avoid failures of clay slopes by correlating the PPV at the soil surface at a given distance from the loading source with the maximum shear strain experienced by the soil medium along a vertical section at the same distance. The validity of the correlation has been verified by numerical analysis using the FLAC2D finite difference program and by a field experiment in a natural soil deposit. The results show good accuracy of the developed equation in calculating the maximum shear strain induced in the soil at a specific section. Moreover, the equation demonstrates independence from the load characteristics at locations distant from the loading area.

A two-dimensional explicit FD program FLAC 2D (Itasca Consulting Group Inc., 2011) model was developed to simulate the seepage flow and evaluate the static performance of the Plovdivtsi ACRD dam. Plate load tests conducted on site during construction were modelled in this study to establish the Duncan-Chang parameters. The calibration of Duncan–Chang parameters is based on the experimental oedometric curves carried out for the Romaine-2 ACRD dam (Lashin et al., 2021). The distribution of stresses and deformations during and at the end of the construction phase, as well as following the first reservoir impoundment, were calculated with numerical analyses. Results expose that the core, the adjacent fill zones and the base of the ACRD dam appear to behave in a similar way, as a retaining wall. Based on these calibrated parameters, the pressure induced by the reservoir displaces the core downstream, favouring the formation of a Vshaped section immediately behind the core on the upstream side with larger vertical displacements in comparison with the whole of the embankment. This contrast in vertical displacements leads to notable differential displacements, which could likely lead to the formation of cracks in the upper part of the upstream dam fill. Although this behaviour is consistent with literature, instrumental data from this dam tends to support that deformations during the first reservoir impoundment would be lower than those calculated with the calibrated model. A sensitivity analysis was carried out to study two scenarios that could result in less deformation during the first reservoir impoundment. One scenario involves doubling rockfill stiffness while the second one is to study the effect of very rapid impoundment, as was the case for this dam, also considering the upstream rockfill shell could possibly be slightly less permeable. This scenario simulates the effects of rapid reservoir impoundment while considering calibrated stiffness parameters in line with the results of plate load tests carried out during construction appear to be the most realistic based on construction data, the first reservoir impoundment conditions and instrumental data.

Blasting operations carried out as part of road projects can generate vibrations that affect the stability of surrounding slopes. However, the effects of these vibrations on clay soils remain poorly documented. To date, few cases of landslides or major deformations have been recorded in these types of soils following blasting. Currently, blasting is controlled by peak particle velocity (PPV) thresholds. In Queébec, existing regulations are becoming increasingly restrictive, leading to a significant increase in blasting costs. This article is a continuation of the recommendations from previous studies, which highlighted a lack of field data on vibrations caused by blasting in sensitive clay deposits, as well as the absence of a clear methodology for carrying out measurements (number of devices, distances between recording sites, etc.). One of the objectives of this article is to show vibration recording data produced by blasting activities in clays in order to gain a better understanding of these problems. As part of this project, two blasting operations were carried out near a clay deposit. Various installation devices and techniques were used to measure vibrations and are presented in this article. These field tests highlighted limitations in the surface recordings, which affect our understanding of blasting wave propagation mechanisms in clay soils. These understanding of blasting wave propagation mechanisms in clay soils. These limitations will be discussed in detail and provide the basis for a subsequent phase of research.

Upon dynamic loading, saturated soils lose their strengths and undergo deformations resulting in volumetric-induced settlements that vary according to the excess pore pressure generation and dissipation variations. Traditionally, these settlements have been evaluated using standard charts based on one soil type and its relative density (RD). To assess these settlements, this study established a unique experimental methodology based on two laboratory testings: triaxial simple shear and piezoelectric ring actuator technique. Fifty-seven tests were performed on Ottawa F65 sand under strain-controlled cyclic and post-cyclic conditions. A chart was generated, revealing a relationship between the dissipated energy from cyclic loading and volumetric strain ( ε v ), based on the shear wave velocity as a controlling factor. This study was compared with previous studies to verify the compatibility of the proposed approach. Another novelty was revealed by studying ε v variation with the dissipated pressure. This variation is presented in a post-seismic chart in which deformations are tracked based on the initial soil state and maximum excess pore pressure generation ratio ( Ru max ) at the end of the loading phase. For each RD, the soil is divided between liquefied and non-liquefied states according to a specific Ru max ( Ru max - trigger point ). The calculation of the volume compressibility coefficient is proven to serve as a liquefaction-triggering criterion identifying the liquefied state.

On February 6th, 2023, southeastern T & uuml;rkiye was shaken by two catastrophic earthquakes, close to northwestern Syrian border. The first earthquake (Pazarc & imath;k) occurred 45 km west of Gaziantep at 1:17:32 (UTC), with a shallow strike-slip faulting at a depth of approximately 8.6 km and a moment magnitude (MW) of around 7.7. The second event (Elbistan) took place 9 h later, 66 km north-east of Kahramanmaras, city center, also with shallow strike-slip faulting at a depth approximately 7 km and an MW of around 7.6. Turkish authorities reported a death toll of over 59,000 in T & uuml;rkiye and about 8500 in Syria. The destructive effect of the earthquake resulted from widespread strong ground shaking, a rupture length exceeding 300 km, causing collapse of a large number of buildings. The catastrophic destruction of the built environment was accompanied by a range of other earthquake-related effects, including fault ruptures, landslides, and soil liquefaction. The aim of the study is to analyze the distribution of ground motion and their relationships with the observed damages for the two events. Spectral accelerations of key importance were assessed across a large area in the southeastern part of T & uuml;rkiye. Notably, these accelerations were generally much higher than existing design spectra. A significant correlation between the observed concentration of damage and the significant amplification of motion induced by local soil conditions (such as soft soils and valley effects). The distinct tectonic structure of the region could be the main reason for the high amplification in the valleys (associated with basin effects), even at large distances from the epicenter, especially in correspondence with the bidimensional grabentype geological structures. The investigation delved into the analysis of four specific regions in detail: Antakya and Hassa (both in the Hatay province), Kahramanmaras, and Goksun. Notably, the observable valley effects were found to play a significant role and could account for the significant damage observed in these regions.

Permeability is a critical parameter that reflects the physical and mechanical states of soil. The variation in permeability through the liquefaction and postliquefaction phases is important in evaluating dynamic soil behavior and establishing adequate numerical models. This aspect has been addressed by several empirical methods. Conversely, in this study, the postseismic behavior of soil was investigated experimentally. Several undrained cyclic strain-controlled and permeability tests on Ottawa C-109 sand, 1-1.3 mm calibrated beads, and blank samples were performed. An experimental strategy is proposed after highlighting the major committed mistakes and factors affecting the permeability variation in a triaxial cell, i.e., the sample's diameter-to-height ratio, stone porosity, flow trajectory, tube diameter, and flow rate. This paper provides suggestions on the experimental setup signature, which frequently results in unreliable measurements. The permeability variation in the postseismic phase was measured during the time history of the excess pore pressure dissipation by following the falling head test rule. Permeability increased, reaching a peak of 2.5-3 times the initial value, and then decreased after a 50% regain of effective stress. The test results were verified by performing permeability tests before cyclic loading and after the dissipation process in triaxial conditions.

The results of cyclic strain-controlled tests performed on reconstituted specimens of Ottawa sand F-65 using the combined triaxial simple shear (TxSS) apparatus were used to establish a strain/energy-based pore pressure model. The model was utilized in conjunction with the sigmoid function (SIG4) to simulate the cyclic behavior of Ottawa F-65 sand under stress and strain loading conditions using FLAC at the element-level and in 1-D effective stress analysis. A counterpart set of cyclic stress-controlled direct simple shear (DSS) tests was performed to assess the predictive capability of the numerical model to determine the liquefaction potential curves. Two dynamic centrifuge tests were simulated using the proposed model and Finn model, and a satisfactory comparison of the observed and computed responses in terms of pore water pressure generation at different depths was obtained. Furthermore, model validation was carried out by applying real earthquakes from the Western United States (WUS) to a hypothetical soil deposit and then comparing the liquefaction triggering according to published liquefaction charts. A good agreement between the numerical results and the published charts confirms the applicability of the proposed strain/energy-based model in 1-D response analysis and liquefaction triggering assessment.

On the 30th of October 2020, a 6.6 magnitude earthquake occurred 14 km north of Samos Island, causing 119 casualties (117 in Izmir, Tu & BULL;rkiye, and 2 in Samos, Greece) and significant damage in the 3rd biggest city of Tu & BULL;rkiye, Izmir. Although the city is roughly 70 km far away from the epicenter, the damage was significant and concentrated in the city center settled on alluviums. This paper aims to analyze the distribution of damage in Izmir province, by crosschecking the recorded motions, the subsoil conditions and the evidence of damage as collected by an ad-hoc on-site reconnaissance. The intrinsic behavior of the Samos earthquake was investigated by employing three different ground-motion prediction equations. The results of the analyses revealed that site effects play a significant role in the amplifi-cation of ground motions, and valley effects are responsible for the concentration of damage. The damage in buildings was classified in terms of the intensity and structural typologies for the 30 districts of Izmir metropolitan area. In-depth analysis of the distribution of damages revealed that the earthquake caused damage all over the boundaries of Izmir province, and the concentration of damage in Bornova and Kars & DBLBOND;iyaka districts has a clear correlation with double resonance effects.& COPY; 2023 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Given the abundance and importance of earth retention structures, the problem of seismic earth pressure has attracted not only the research community but also industry and government establishments. The dynamic response, even in the case of the simplest retaining wall, presents a complex problem of soil–structure interaction, encompassing a multitude of competing and complementary factors. This article presents a thorough and critical evaluation of notable analytical and field studies related to the dynamic earth pressures acting on retaining walls. Despite numerous studies spanning nearly a century regarding seismically induced lateral earth pressures, there remains a noticeable disparity between theoretical understanding and the actual field performance of retaining structures during seismic events. This review underscores the necessity for a more meticulous examination of dynamic analysis techniques and the existing design methodologies for retaining structures.