Two earthquakes, Mw = 7.8 Kahramanmaras,-Pazarcik, and Mw = 7.6 Elbistan, occurred on February 6, 2023, approximately 9 h apart. These earthquakes caused devastating effects in a total of 11 nearby cities on the east side of T & uuml;rkiye (Adana, Adiyaman, Diyarbakir, Elazig, Gaziantep, Hatay, Kahramanmaras,, Kilis, Malatya, Osmaniye, and S,anliurfa) and the north side of Syria. These earthquakes provided an outstanding prospect to observe the effects of liquefaction in silty sand and liquefaction-like behavior in clays (cyclic softening) on the stability of structures. This paper specifically presents the post-earthquake reconnaissance at three sites and evaluations of four buildings within these sites in Adiyaman Province, Golbas, i District. First, important role of post-earthquake piezocone penetration test (CPTu) in characterizing the subsurface conditions was presented. Then, the effect of soil liquefaction and cyclic softening on the performance of four buildings during the earthquakes was evaluated. These structures represent the typical new reinforced concrete buildings in T & uuml;rkiye with 3 to 6-story, situated on shallow (raft) foundations, and demonstrated diverse structural performances from full resilience to moderate and extensive damage during the aforementioned earthquakes. Based on the interim findings from these sites, the potential factors that caused moderate to severe damage to buildings were inspected, and preliminary-immediate insights were presented on the relationship between structural design, soil properties, and the performance of buildings with shallow foundations.

To comprehensively understand the explosion risk in underground energy transportation tunnels, this study employed computational fluid dynamics technology and finite element simulation to numerically analyze the potential impact of an accidental explosion for a specific oil and gas pipeline in China and the potential damage risk to nearby buildings. Furthermore, the study investigated the effects of tunnel inner diameter (d = 4.25 m, 6.5 m), tunnel length (L = 4 km, 8 km, 16 km), and soil depth (primarily L-soil = 20 m, 30 m, 40 m) on explosion dynamics and on structural response characteristics. The findings indicated that as the tunnel length and inner diameter increased, the maximum explosion overpressure gradually rose and the peak arrival time was delayed, especially when d = 4.25 m; with the increase in L, the maximum explosion overpressure rapidly increased from 1.03 MPa to 2.12 MPa. However, when d = 6.5 m, the maximum explosion overpressure increased significantly by 72.8% from 1.25 MPa. Evidently, compared to the change in tunnel inner diameter, tunnel length has a more significant effect on the increase in explosion risk. According to the principle of maximum explosion risk, based on the peak explosion overpressure of 2.16 MPa under various conditions and the TNT equivalent calculation formula, the TNT explosion equivalent of a single of the tunnel was determined to be 1.52 kg. This theoretical result is further supported by the AUTODYN 15.0 software simulation result of 2.39 MPa (error < 10%). As the soil depth increased, the distance between the building and the explosion source also increased. Consequently, the vibration peak acceleration and velocity gradually decreased, and the peak arrival time was delayed. In comparison to a soil depth of 10 m, the vibration acceleration at soil depths of 20 m and 30 m decreased by 81.3% and 91.7%, respectively. When the soil depth was 10 m, the building was at critical risk of vibration damage.

Traditional suction bucket foundations incur high maintenance costs and are susceptible to corrosion, resulting in a diminished bearing capacity over prolonged service. The suction bucket foundation, constructed with a glass fibre -reinforced polymer (GFRP), introduces a novel approach to iteratively optimise conventional steel bucket foundations. In this study, three-dimensional finite element models of the GFRP bucket -soil interaction were established using the VUMAT subroutine, which incorporates the stress -strain damage relationship of GFRP materials. The mechanical response during installation was analyzed for different fibre -laying angles( A ) and wall thicknesses( t ) of the GFRP bucket, and the results were compared with those of a steel bucket. The results indicated increased circumferential stress, radial deformation, and out -of -roundness of the GFRP bucket as the fibre laying angle increased. Deformation and stress of the bucket skirt remained low at A of 0 - 45 degrees . When A >= 60 degrees , the matrix ' s damage area significantly increases, with the minimum damage occurring at 45 degrees . For A <= 30 degrees , it approaches the maximum radial deformation of an equivalent -sized steel suction bucket. As the wall thickness increased, the circumferential stress, radial deformation, and out -of -roundness of the GFRP bucket skirt gradually decreased. When the GFRP bucket t was four times that of the steel bucket, its radial deformation was approximately equal.