To investigate the effect of interface temperature on the soil-reinforcement interaction mechanism, a series of pullout tests were conducted considering different types of reinforcement (geogrid and non-woven geotextile), backfill (dry sand, wet sand, and clay), and six interface temperatures. The test results indicate that at interface temperatures of 0 degrees C and above, reinforcement failure didn't occur during the pullout tests, whereas it predominantly occurred at subzero temperatures. Besides, the pullout resistance for the same soil-reinforcement interface gradually decreased as the interface temperature rose. At a given positive interface temperature, the pullout resistance between wet sand and reinforcement was significantly higher than that of the clayreinforcement interface but lower than that of the dry sand-reinforcement interface. Compared with geotextile reinforcements, geogrids were more difficult to pull out under the same interface temperature and backfill conditions. In addition, the lag effect in the transfer of tensile forces within the reinforcements was significantly influenced by the type of soil-reinforcement interface and the interface temperature. Finally, the progressive deformation mechanism along the reinforcement length at different interface temperatures was analyzed based on the strain distribution in the reinforcement.

Ensuring the accuracy of free-field inversion is crucial in determining seismic excitation for soil-structure interaction (SSI) systems. Due to the spherical and cylindrical diffusion properties of body waves and surface waves, the near-fault zone presents distinct free-field responses compared to the far-fault zone. Consequently, existing far-fault free-field inversion techniques are insufficient for providing accurate seismic excitation for SSI systems within the near-fault zone. To address this limitation, a tailored near-fault free-field inversion method based on a multi-objective optimization algorithm is proposed in this study. The proposed method establishes an inversion framework for both spherical body waves and cylindrical surface waves and then transforms the overdetermined problem in inversion process into an optimization problem. Within the multi-objective optimization model, objective functions are formulated by minimizing the three-component waveform differences between the observation point and the delayed reference point. Additionally, constraint conditions are determined based on the attenuation property of propagating seismic waves. The accuracy of the proposed method is then verified through near-fault wave motion characteristics and validated against real downhole recordings. Finally, the application of the proposed method is investigated, with emphasis on examining the impulsive property of underground motions and analyzing the seismic responses of SSI systems. The results show that the proposed method refines the theoretical framework of near-fault inversion and accurately restores the free-field characteristics, particularly the impulsive features of near-fault motions, thereby providing reliable excitation for seismic response assessments of SSI systems.

Characterizing vertical profiles of in-situ particle properties is relevant because being only based on the surface or column-integrated measurements cannot unambiguously conclude the radiative impact on aerosol. Vertical profiles of in-situ aerosol properties on-board an unmanned aerial vehicle (UAV) were measured above El Arenosillo (37.1 N,-6.7 W) in the southwest of Spain during four flight missions. Measured properties included particle number size distribution, total particle concentration and multiwavelength absorption coefficient up to 3100 m during cold season (February 4, 2022 and December 11, 2023) and warm season (September 20, 2023 and April 2, 2024). The heterogeneity of particle properties has been shown around two types of events: a mineral particle event of desert origin during cold season and a new particle formation event during warm season. During cold season, a comparison between the flight missions with and without desert dust episodes shows that mineral particles decrease the planetary boundary layer (PBL) height. This behavior is probably related to absorber particles aloft atmosphere, which traps solar radiation and heat up the upper layer of the atmosphere and deteriorates the vertical dispersion. In the literature, this effect is called as 'dome effect'. During warm season, new particle formation was observed above PBL. This event could be related to the presence of precursor gases in the residual layer, and enhanced by a low concentration of pre-existing particles. The characteristic parameter during the observed event was the fine-to-total particle volume concentration ratio close to zero. These observations highlight the necessity to establish a long-term multi-temporal monitoring of vertical profiles for atmospheric parameters onboard UAV systems and to integrate in Earth observations networks. For example, radiative forcing is usually estimated from surface data, but the heterogeneity in the vertical profiles of atmospheric particles properties, which are used to the forcing quantification, is a result of inaccuracies.

Pile foundations are frequently used in the construction of bridges, offshore platforms, and offshore wind turbines, which are often subjected to complex lateral cyclic loading from wind, wave, or current. These lateral loads usually come from different directions or constantly change their direction, which is ignored by most existing calculation models. A two-dimensional p -y model is proposed in this study for the lateral response of the pile subjected to multi-directional cyclic loading in sand. Without introducing additional parameters, the p -y response in two dimensions is coupled by developing the model within the framework of the bounding surface p -y model. Combined with the collapse and recompression model, the effect of sand collapse around the pile during cyclic loading is considered to approach reality. The pile lateral displacement and soil resistance are obtained in incremental form using the finite difference method in the two-dimensional case. By comparing with the model test results, it is demonstrated that the proposed model is able to reasonably predict the lateral cyclic response of the pile as well as the effects of multi-directional cyclic loading. The distribution and variation characteristics of the soil resistance are further discussed by analyzing the results calculated by the proposed model.

The application of prefabricated assembly technology in underground structures has increasingly garnered attention due to its potential for urban low-carbon development. However, given the vulnerability of such structures subjected to unexpected seismic events, a resilient prefabricated underground structure is deemed preferable for mitigating seismic responses and facilitating rapid recovery. This study proposes a resilient slip-friction connection-enhanced self-centering column (RSFC-SCC) for prefabricated underground structures to promote the multi-level self-centering benefits against multi-intensity earthquakes. The RSFC-SCC is composed of an SCC with two sub-columns and a series of multi-arranged replaceable RSFCs, intended to substitute the fragile central column. The mechanical model and practical manufacturing approach are elucidated, emphasizing its potential multi-level self-centering benefits and working mechanism. Given the established simulation model of RSFC-SCC-equipped prefabricated underground structures, the seismic response characteristics and mitigation capacity are investigated for a typical underground structure, involving robustness against various earthquakes. A multi-level self-centering capacity-oriented design with suggested parameter selection criteria is proposed for the RSFC-SCC to ensure that prefabricated underground structures achieve the desired vibration mitigation performance. The results show that the SCC with multi-arranged replaceable RSFCs exhibits a significant vibration isolating effect and enhanced self-centering capacity for the entire prefabricated underground structure. Benefiting from the multi-level self-centering process, the RSFC-SCC illustrates a robust capacity that adapts to varying intensities of earthquakes. The multi-level self-centering capacity-oriented design effectively facilitates the target seismic response control for the prefabricated underground structures. The energy dissipation burden and residual deformation of primary structures are mitigated within the target performance framework. Given the replacement ease of RSFCs and SCC, a rapid recovery of the prefabricated underground structure after an earthquake is ensured.

Forests are increasingly impacted by climate change, affecting tree growth and carbon sequestration. Tree-ring width, closely related to tree growth, is a key climate proxy, yet models describing ring width or growth often lack comprehensive environmental data. This study assesses ERA5-Land data for tree-ring width prediction compared to automatic weather station observations, emphasizing the value of extended and global climate data. We analyzed 723 site-averaged and detrended tree-ring chronologies from two broadleaved and two gymnosperm species across Europe, integrating them with ERA5-Land climate data, CO2 concentration, and a drought index (SPEI12). A subset was compared with weather station data. For modelling interannual variations of tree-ring width we used linear models to assess parameter importance. ERA5-Land and weather-station-based models performed similarly, maintaining stable correlations and consistent errors. Models based on meteorological data from weather stations highlighted SPEI12, sunshine duration, and temperature extremes, while ERA5-Land models emphasized SPEI12, dew-point temperature (humidity), and total precipitation. CO2 positively influenced the growth of gymnosperm species. ERA5-Land facilitated broader spatial analysis and incorporated additional factors like evaporation, snow cover, and soil moisture. Monthly assessments revealed the importance of parameters for each species. Our findings confirm that ERA5-Land is a reliable alternative for modeling tree growth, offering new insights into climate-vegetation interactions. The ready availability of underutilized parameters, such as air humidity, soil moisture and temperature, and runoff, enables their inclusion in future growth models. Using ERA5-Land can therefore deepen our understanding of forest responses to diverse environmental drivers on a global scale.

This paper deals with the contribution of the soil-structure interaction (SSI) effects to the seismic analysis of cultural heritage buildings. This issue is addressed by considering, as a case study, the Mosque-Cathedral of Cordoba (Spain). This study is focussed on the Abd al-Rahman I sector, which is the most ancient part, that dates from the 8th century. The building is a UNESCO World Heritage Site and it is located in a moderate seismic hazard zone. It is built on soft alluvial strata, which amplifies the SSI. Since invasive tests are not allowed in heritage buildings, in this work a non-destructive test campaign has been performed for the characterisation of the structure and the soil. Ambient vibration tests have been used to calibrate a refined 3D macro-mechanical-based finite element model. The soil parameters have been obtained through an in situ geotechnical campaign, that has included geophysical tests. The SSI has been accounted for by following the direct method. Nonlinear static and dynamic time-history analyses have been carried out to assess the seismic behaviour. The results showed that the performance of the building, if the SSI is accounted for, is reduced by up to 20 % and 13 % in the direction of the arcades and in the perpendicular direction, respectively. Also, if the SSI is taken into account, the damage increased. This study showed that considering the SSI is important to properly assess the seismic behaviour of masonry buildings on soft strata. Finally, it should be highlighted that special attention should be paid to the SSI, which is normally omitted in this type of studies, to obtain a reliable dynamic identification of the built heritage.

Energy piles, which serve the dual functions of load-bearing and geothermal energy exchange, are often modeled with surrounding soil assumed to be either fully saturated or completely dry in existing design and computational methods. These simplifications neglect soil saturation variability, leading to reduced predictive accuracy of the thermomechanical response of energy piles. This study proposes a novel theoretical framework for predicting the thermo-hydro-mechanical (THM) behavior of energy piles in partially saturated soils. The framework incorporates the effects of temperature and hydraulic conditions on the mechanical properties of partially saturated soils and pile-soil interface. A modified cyclic generalized nonlinear softening model and a cyclic hyperbolic model were developed to describe the interface shear stress-displacement relationship at the pile shaft and base, respectively. Governing equations for the load-settlement behavior of energy piles in partially saturated soils were derived using the load transfer method (LTM) and solved numerically using the matrix displacement method. The proposed approach was validated against experimental data from both field and centrifuge tests, demonstrating strong predictive performance. Specifically, the average relative error (ARE) was less than 15% for saturated soils and below 23% for unsaturated soils when evaporation effects were considered. Finally, parametric analyses were conducted to assess the effects of flow rate, groundwater table position, and softening parameters on the THM behavior of energy piles. This framework can offer a valuable tool for predicting THM behavior of energy piles in partially saturated soils, supporting their broader application as a sustainable foundation solution in geotechnical engineering.

This study aims to assess the effectiveness of inter-storey isolation structures in reducing seismic responses in super high-rise buildings, with a focus on analyzing the impact of soil-structure interaction (SSI) on the dynamic performance of the buildings. Utilizing the lumped parameter SR (Sway-Rocking) model, which separately simulates the overall displacement of the super high-rise structure and the rotational motion of the foundation, the dynamic characteristic parameters of the simplified model are derived. The natural frequencies of the system are calculated by solving the equations of motion. The study examines the influence of parameters such as soil shear wave velocity and structural damping ratio on the dynamic response of the structure, with particular emphasis on displacement transfer rates. The findings indicate that inter-storey isolation structures are highly effective in reducing displacement responses in super high-rise buildings, especially when considering SSI effects. Specifically, for high-damping inter-storey isolation structures, modal frequencies decrease as soil shear wave velocity decreases. In non-isolated structures, the damping ratio increases with decreasing soil shear wave velocity, whereas for isolated structures, the damping ratio decreases, with a more pronounced reduction at higher damping ratios. Increasing damping significantly reduces inter-storey displacement and damage indices. However, under low shear wave velocity conditions, inter-storey isolation structures may experience increased displacement and damage.

The foundation conditions of piers for multi-span long-distance heavy-haul railway bridges inevitably vary at different locations, which may lead to non-uniform ground motions at each pier position, potentially causing adverse effects on the bridge's seismic response. To investigate the seismic response of bridges and the running safety of heavy-haul trains as they cross the bridge during an earthquake, a three-dimensional heavy-haul railway train-track-bridge (HRTTB) coupled system model was developed using ANSYS/LS-DYNA. This model incorporates the nonlinear behavior of critical components such as bearings, lateral restrainers, piers, and wheel-rail contact interactions, and it has been validated against field-measured data to ensure reliable dynamics parameters for seismic analysis. A multi-span simply supported girder bridge from a heavy-haul railway (HHR) was employed as a case study, in which a spatially correlated non-stationary ground motion field was generated based on spectral representation harmonic theory. Comparative analyses of the seismic responses under spatially varying ground motions (SVGM) and uniform seismic excitation conditions were performed for the coupled system. The results indicate that the presence of heavy-haul trains prolongs the natural period of the HRTTB system, thereby appreciably altering its seismic response. At lower apparent wave velocities, more piers exhibit a low-response state, and some pier bases enter the elastic-plastic stage under local site effects. Compared with the piers, the bearings show higher sensitivity to seismic inputs; fixed bearings experience damage when subjected to traveling wave effects and local site effects, which is subsequently followed by the failure of lateral restrainers. Train running safety is markedly reduced when crossing local soft soil site conditions. The conclusions drawn from this study can be applied in the seismic design and running safety assessment of HHR bridge systems under SVGM.