This paper establishes a novel full-process numerical simulation framework for analyzing the 3D seismic response of mountain tunnels induced by active faults. The framework employs a two-step approach to achieve wavefield transmission through equivalent seismic load: first, a highly efficient and accurate FMIBEM (Fast multipole indirect boundary element method) is used for large-scale 3D numerical simulations at the regional scale to generate broadband ground motions (1-5 Hz) for specific sites; subsequently, using the FEM (Finite element method), a refined simulation of the plastic deformation of surrounding rock and the elastoplastic behavior of the tunnel structure was conducted at the engineering scale. The accuracy of the framework has been validated. To further demonstrate its effectiveness, the framework is applied to analyze the impact of different fault movement mechanisms on the damage to mountain tunnels based on a scenario earthquake (Mw 6.7). By introducing tunnel structure damage classification and corresponding damage indicators, the structural damage levels of tunnels subjected to active fault movements are quantitatively evaluated. The findings demonstrate that the framework successfully simulates the entire process, from fault rupture and terrain amplification to the seismic response of tunnel structures. Furthermore, the severity of tunnel damage caused by different fault types is ranked as follows: reverse fault > normal fault > strike-slip fault.

This paper describes the construction of a deep basement in central London. The construction sequence for the basement was a combination of top down and blue-sky excavation to enable phased delivery of the project. Temporary single level props enabled blue-sky construction by managing ground movements. Ground movements associated with the basement construction and impact on 3rd party assets were monitored to validate the design using 3D targets and inclinometers. The ground movements were predicted at each stage of construction using simple models with more complex three-dimensional soil-structure finite element analysis used when examining the whole basement behaviour under the temporary and permanent loads. Temporary prop loads, and thermal loads on props were also monitored during the bulk digging. The small strain constitutive models for London Clay was shown to closely predict the observed movements.

Recent earthquakes have highlighted the importance of earthquake ground motion recordings and rapid visual inspections (RVSs) of damaged buildings to assess the earthquake impact on the building inventory, prepare recovery plans, and provide valuable findings that could contribute to the preparedness ahead of future earthquake events. The effect of strong earthquake ground motions on the building stock is controlled by a range of interconnected factors. These include the intensity of ground motion, the effects of local soil conditions, the structural design, reinforcement and material properties, as well as the quality control during construction, among others. However, it is important to acknowledge that the earthquake ground motions recorded are dependent on local variables, such as the soil type and potential operational issues. Such an example is the major M6.4 earthquake in Durr & euml;s, Albania, in November 2019, the most significant in the region in the past four decades. The strong ground motion recorded at the sole Durr & euml;s accelerometric station was interrupted due to a power outage. As a result, the recorded accelerograms (with a PGA of 0.192 g) require thorough analysis and evaluation before they can be reliably used in assessing damage of existing structures. The current paper presents a framework for evaluating the incomplete record to ensure that the strong ground motion pulse is captured in the acceleration series. The latter is achieved by analyzing and comparing the amplitude and frequency contents of the recorded motion against ground motion accelerograms from areas with similar seismotectonic features. Ground motion recordings from stations that have soil conditions resembling those of the Durr & euml;s region are used, ensuring that the analysis is relevant to the specific study area. Next, the disrupted ground motion recording is evaluated by comparing the damage of post-earthquake inspected buildings with the results of advanced numerical analysis for the case of a typical 12-storey and a 5-storey building. The effects of pounding, the presence of infills, soil-structure interaction (SSI), and multiple failure modes are taken into consideration. Results indicate that despite the incomplete data, the seismic record retains the essential strong ground motion features and can be used for further studies. The numerical simulations aligned well with observed damage from rapid visual inspections, verifying the record's integrity. The findings show that factors such as soil-structure interaction, infill panels, and pounding effects significantly influenced building performance. The study concludes that the Durr & euml;s record, though incomplete, is reliable for seismic assessment and can aid future risk studies in the region.

This article investigates the influence of climatic and geographical characteristics in south-western region of Bangladesh on the temporal dynamics of post-cyclone impacts, with a critical focus on biophysical contexts. By quantitatively assessing the environmental consequences of cyclones Amphan (2020), Yaas (2021), Mocha (2023) and Remal (2024), the study offers a nuanced understanding of flood damage extent and vegetation health, measured through advanced remote sensing and geospatial techniques. Using Sentinel-1 (GRD) and Sentinel-2 (MSI) satellite imageries from 2020 to 2024, the study has examined post-cyclone changes of vegetation health and flood damage extent using available indices such as Normalized Difference Vegetation Index (NDVI) and Soil-Adjusted Vegetation Index (SAVI). The results exhibit substantial spatial disparities occurred due to the cyclone events, with NDVI variations ranging from - 0.124 to 0.546 (Amphan), - 0.033 to 0.498 (Mocha), - 0.086 to 0.458 (Yaas), and - 0.061 to 0.362 (Remal), indicating significant ecological stress. Corresponding SAVI changes ranged from - 0.001 to 0.396 (Amphan), - 0.029 to 0.338 (Mocha), - 0.002 to 0.345 (Yaas), and - 0.0524 to 0.269 (Remal). Negative indices underscore potential vegetation degradation, while positive values indicate resilience or post-cyclone recovery. Furthermore, flood damage analysis indicates to a more severe and unevenly distributed impact than previously recognized, particularly in areas with pre-existing vulnerabilities with the damage extent variations between - 35.918 to - 2.0093 (Amphan), - 35.334 to - 4.4059 (Mocha), - 34.806 to - 0.94921 (Yaas), and - 48.469 to 0.00255 (Remal). The Geographically Weighted Regression (GWR), model demonstrates a robust relationship, with r2 values of 0.894, 0.889, 0.899, and 0.95, indicating that approximately 85% of the ecological changes are driven by fluctuations of vegetation due to flood. The insight from this research provides a foundation of flood damage assessment technique occurred by cyclones in a short span of time to aid immediate policy recommendations to enhance resilience in remote areas of the coastal regions of Bangladesh.

The underground concrete silo, designed as a hollow cylinder with a large aspect ratio and thin walls, is highly susceptible to failure caused by intentional or accidental soil explosions. To enhance its protection, this study investigates the dynamic tensile responses and failure mechanisms of underground concrete silos subjected to high-yield soil explosions. The concept of nominal crack width is proposed to quantitatively describe the degree of overall bending-induced tensile responses and failure of the concrete silo. The influences of explosive weights, standoff distances, and the aspect ratios and thicknesses of the underground concrete silo are quantitatively explored first. On this basis, a dimensionless number combining these major influencing factors is derived using dimensional analysis. The derived dimensionless number has a clear physical meaning, reflecting three aspects: the inertia of the blast loading, the resistance ability of concrete material to bending responses and failure, and the resistance ability of silo structure to bending responses and failure. The results demonstrate that the proposed dimensionless number effectively correlates with the overall bending-induced tensile responses and failure of silo structures across various geometries and explosion scenarios, exhibiting a good linear relation with the dimensionless nominal crack width of the concrete silo. With its solid physical foundation, the dimensionless number offers practical applications in scaling analysis and fast damage assessment. Specific examples of these applications are presented and discussed in this study.

This paper has attempted to determine the weighting levels of the soil and ground motion parameters (engineering bedrock depth (EBd), average shear wave velocity (Vs30), fundamental frequency (f0), peak ground acceleration (PGA), Joyner-Boore distance (Rjb), and epicenter distance (Repi)) in reflecting the actual damage status after the 2023 Kahramanmara & scedil; earthquakes, which have a wide impact area of 11 provinces. The analytical hierarchy method (AHP), a multi-criteria decision-making (MCDM) process, was used to analyze these parameter data sets obtained from 44 Disaster and Emergency Management Presidency of T & uuml;rkiye (AFAD) stations (Gaziantep, Hatay, Kahramanmara & scedil;, and Osmaniye). The priority order of the parameters before the analysis was systematically collected. These parameters were categorized into soil, ground motion and earthquake source-path properties. Considering the literature, these characteristics and their combined effects were systematically weighted with AHP under five groups. According to the weighted groups in the scope of the study, the actual damage data can be determined with a minimum accuracy rate of 70% (Group 1). In comparison, the best performance evaluation was 82% (Group 5). The parameter order and weights in the actual damage data evaluation are suggested as EBd-%28, PGA-%24, Vs30-%19, Rjb-%14, f0-%10, and Repi-%5 considering the very high accuracy rate of Group 5. This suggested weighting allows the rapid and effective estimation of the damage distribution after a possible earthquake only with soil, ground motion and earthquake source-path characteristics, even in cases where reliable structure data cannot be obtained.

Based on a prototype of the Beijing subway tunnel, this research conducts large-scale model experiments to systematically investigate the vibration response patterns of tunnels with different damage levels under the influence of measured train loads. Initially, the polynomial fitting modal identification method (Levy) and the model test preparation process are introduced. Then, using time-domain peak acceleration, frequency response function, frequency-domain modal frequency, and modal shape indicators, a detailed analysis of the tunnel's dynamic response is conducted. The results indicate that damage significantly amplifies vibration acceleration, with the amplification increasing with the severity of the damage. When the crack lengths are 2 cm, 4 cm, and 6 cm, the peak acceleration increases by 25.12%, 36.35%, and 50.29%, respectively, while adjacent segments show increases of 13%, 29%, and 45%. Damage decreases the tunnel structure's modal frequency, with the first two modal frequencies showing the most significant reductions of 9.87% and 7.34%, respectively. The adjacent segments show reductions of 7.7% and 4.2%. As the severity of the damage increases, the amplitude of the modal shape at the damaged location also increases, with the first modal shape rising by 43.37% for 4 cm damage compared to 2 cm damage and by 72.21% for 6 cm damage. The second modal shape increases by 9.04% and 26.51%, respectively. Additionally, the effectiveness of the polynomial fitting modal identification method (Levy) for tunnel structural damage detection was validated. Finally, based on the methods outlined above, the tunnel responses measured on-site in the Beijing metro were also analyzed. The findings of this study provide important theoretical support for the assessment and routine maintenance of metro tunnels.

Bridge abutments are often damaged by girder impacts during major earthquakes. Very limited studies have been conducted. None of the past studies have incorporated abutment damage as an integrated system, i.e. the interaction between the deck and the back wall as well as between abutment and backfill. First, the reliability of the numerical model for damage assessment is validated with the result obtained from the shaking table test. Second, numerical simulations of the impact effect were carried out on four abutments with different shapes and dimensions of wing wall. The developed numerical models can simulate the nonlinear backfill soil, the backfill-back wall interface, and damage to reinforced concrete with the strain rate effect of the concrete and steel reinforcement. Parametric studies were conducted on the influence of the nonlinearity of the backfill soil, back wall-to-backfill friction, constitutive law of concrete, hourglass ratio, and impact energy. The results show that the nonlinear behaviour of the backfill soil and wing wall plays a significant role in the impact force on the back wall behaviour. Since poundings can be repetitive, this study confirms that the velocity of the initial impact of a bridge deck can precisely predict the severity of abutment damage.

This paper presents the findings of field observations conducted in the aftermath of the earthquakes that struck the Pazarcik (Mw7.7) and Elbistan (Mw7.6) in Kahramanmaras province, Turkey on February 6th, 2023. The earthquakes, occurring on the East Anatolian Fault Zone (EAFZ), resulted in more than 50,000 losses of life and damage of more than 1.5 million properties across 11 provinces in Turkey. Field observations presented herein encompass seismological and strong ground motion data, geotechnical observations, as well as damage assessments of underground and above ground structures in various provinces and districts. The types and reasons of the structural damages were discussed. The study also examined the effects of high acceleration values and distribution of strong ground motions on the performance of structures. Soil liquefaction problems were observed in many locations such as Golbasi and Iskenderun. The paper highlights the geology, tectonics, strong motion characteristics, surface deformations, geotechnical and structural aspects, and the evaluation of lifelines in the affected area. Furthermore, the authors provide initial recommendations for improving disaster management, evaluating building stock, prioritizing urban transformation, strengthening infrastructure systems, addressing soil-building interaction issues, ensuring security measures during search and rescue efforts, utilizing satellite imagery effectively, considering seismic effects on water infrastructure, and taking a holistic approach to earthquake effects in industrial facilities.

Excessive ground deformation caused by shield tunnelling is prone to irregular settlement and deformation cracking of the overlying building. Hence, accurately assessing the extent of damage to the building is crucial for the effective strengthening and repair of the structure. This paper presents a comprehensive case study of a metro shield tunnel conducted beneath a masonry building. We systematically monitored and investigated the settlement and crack development of the masonry building and discovered that the cracks in the masonry building were mainly situated at the maximum slope of the building settlement curve, rather than at the peak. After completion of the tunnel construction, the maximum settlement of the masonry building was 37 mm and the cracks were predominantly oblique cracks with a length of 0.6-7.6 m and a width of 0.5-5.0 mm. The maximum principal tensile strain in the walls of the masonry building was 0.153%, and the masonry building was evaluated to be moderately damaged according to the assessment criteria considering the extent of damage to the building surface. Then, we proposed a building damage assessment method that considers soil-structure interaction and subsequently verified it through finite-element results and field monitoring results. Finally, the effects of key parameters on the stiffness of the building were analyzed. The stiffness of the building was mainly affected by the opening ratio and the effective coefficient of the building cross section. These research results have significant guiding and reference values for safeguarding buildings during metro tunnel construction.