Bridges with shallow foundations are highly susceptible to flood scouring due to their limited embedment depth and small contact area between the soil and foundation. This can lead to foundation voids, posing a serious threat to bridge safety. To prevent and mitigate scouring risks, this paper investigates the riverbed scouring characteristics of shallow foundation bridges under different hydrological conditions.The study found that under high water levels and flow velocities, scour depth significantly increased.Under extreme hydrological conditions, a horseshoe vortex forms at the base of the front end of the bridge pier, causing scour pits on both sides of the upstream face of the foundation, which is the main cause of foundation voids that first appear at 2580 s with a maximum scour depth of -2.51 m and a void area of 0.5%, continuing to increase over time.Based on simulated scouring data, this study proposes a method for converting boundary conditions from a scouring model to a mechanical model. This method utilizes point cloud reverse engineering technology to generate a riverbed surface from the three-dimensional coordinate matrix of the boundary and import it into the structural analysis field. Hydraulic effects are calculated using a CFD model and transferred to the structural domain through fluid-structure interaction technology, achieving multi-physical field coupling among water flow, soil, and structure. This method addresses the current limitations in simulating complex scouring forms in bridge flood damage research, providing reliable technical support for subsequent studies on the damage behavior of shallow foundation bridges under flood scouring conditions.

The main purpose of this article is to evaluate the influence of sand-gravel quarrying from the river bed on the bed deformation and the environment. Sand and gravel reserves are the second largest produced and traded resource after water. Every year, the demand for these materials in the world is 40-50 billion m3. Large-scale quarrying of sand and gravel from sea coasts and river beds leads to serious problems. Thus, the sand and gravel quarried from the sea shores cause flooding of the coastal zones, and the quarrying from the river beds leads to strong deformations. The sand resources produced from the seashores in Azerbaijan do not meet the current growing demand in the ever-expanding construction sector, and at the same time, they do not meet the quality standards. Therefore, the quarrying of sand and gravel from river beds has become an increasingly important process. Production of sand and gravel from river beds seriously impacts not only bed deformation but also the environment, flora, and fauna. The expansion of the river bed has led to the destruction of the forest areas, and the deepening has led to the depletion and disappearance of fish resources. Excavation works in the river bed also affect the infrastructure. Thus, the soil-cement road passing near the area where the excavation works were carried out, the bridge, and the electric columns have undergone influence. Therefore, as a result of the impact of anthropogenic factors in the Valvalachay River, the damage it caused to the environment was studied. Many parameters were measured in the Valvelachay River, and water consumption entering and leaving the holt was compared. For observation of changes along the river, a longitudinal profile in the study area was compiled based on the DEM (Digital Elevation Model) and topographic measurements in the ArcGIS program. Based on topographical and bathymetric measurements, it was determined that the depth in the part where the bed is deepened (the place where cobble gravel is mined) varies between 1.5-2 meters.