Due to the insufficient burial depth of shallow-buried foundation bridges, foundation voiding easily occurs during floods or rapid water flows. When heavy vehicles pass over these partially voided bridges, the stress state of the foundation deteriorates instantaneously, causing critical components to exceed their load-bearing capacity in a short period, leading to a chain reaction that results in the rapid collapse and overall failure of the bridge structure. Previous numerical simulations of bridge water damage often neglected the strong coupling between water flow, soil, and structure during the scouring process. This paper applies a fluid-solid coupling simulation modeling method for bridge damage behavior under scouring action to study the structural damage behavior of shallow-buried foundation bridges under the combined effects of flood scouring and heavy vehicle load. This method employs point cloud reverse engineering technology to solve the difficult problem of converting the complex scour morphology around the foundation under flood scouring into a structural model, and investigates the multi-hazard damage behavior of shallow-buried foundations by coupling extreme hydraulic effects on the pier surface and placing the most unfavorable heavy vehicle loads on the bridge deck.

Buried steel gas pipelines are increasingly facing safety challenges due to the escalating traffic loads and varying burial depths, which could potentially lead to hazards such as leakage, fire, and explosion. This paper investigates stress mechanisms in buried steel gas pipelines subjected to vehicular loading through integrated analytical approaches. Theoretical modeling incorporates three key components: dynamic vehicle load characteristics, soil-pipeline interaction pressures, and stress distribution angles across pipeline cross-sections. Stress variations are systematically quantified under varying soil conditions and load configurations. A finite-element model was developed to simulate pipeline responses, with computational results cross-validated against theoretical predictions to establish stress profiles under multiple operational scenarios. Additionally, this paper employ fatigue accumulation damage and reliability theories, utilizing Fe-Safe software to evaluate pipeline reliability, determining fatigue life and strength coefficients for various loads and burial depths. Based on these analyses, this paper develop risk control measures and protective methods for buried steel gas pipelines, validated through finite-element and fatigue analyses. Overall, this paper offers insights for preventing and controlling risks to buried steel gas pipelines under vehicle loads.

During the operation period of a red clay low embankment, significant uneven settlement can occur due to vehicle loads, seriously threatening the smooth flow of roads and transportation safety. To better inform the design and filling of red clay low embankment road structures, this study combines model tests and numerical simulations to investigate the dynamic response characteristics of various pavement structures on red clay low embankments under vehicular loads. It examines how different moisture contents, embankment parameters, driving parameters, and pavement structures affect the vertical dynamic stress, acceleration, and deformation of red clay low embankments. The results show that the vertical dynamic stress and acceleration decrease rapidly along the depth and transverse width directions, and then slowly decrease. Increased vehicle loads and speeds lead to greater vertical dynamic stress and acceleration, whereas higher elastic modulus and embankment soil thickness result in lower values. Additionally, increasing water content intensifies the vertical acceleration response in red clay low embankments. The influence degree of different factors on the dynamic characteristics of red clay low embankment is: vehicle load > driving speed > embankment thickness > elastic modulus of embankment soil. The red clay low embankment under vehicular loading belongs to the deformation concentration area within 0 to 0.4 m from the top surface of the embankment. A comparative analysis of the dynamic characteristics of six common pavement structures for red clay low embankments shows that rutting-resistant pavement structures perform the best. The proposed new type of red clay low embankment upper pavement structure can effectively avoid the problem of base water damage caused by the capillary water rise of red clay.

A complete road-soft ground model is established in this paper to study the dynamic responses caused by vehicle loads and/or daily temperature variation. A dynamic thermo-elastic model is applied to capturing the behavior of the rigid pavement, the base course, and the subgrade, while the soft ground is characterized using a dynamic thermo-poroelastic model. Solutions to the road-soft ground system are derived in the Laplace-Hankel transform domain. The time domain solutions are obtained using an integration approach. The temperature, thermal stress, pore water pressure, and displacement responses caused by the vehicle load and the daily temperature variation are presented. Results show that obvious temperature change mainly exists within 0.3 m of the road when subjected to the daily temperature variation, whereas the stress responses can still be found in deeper places because of the thermal swelling/shrinkage deformation within the upper road structures. Moreover, it is important to consider the coupling effects of the vehicle load and the daily temperature variation when calculating the dynamic responses inside the road-soft ground system. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Urban road disasters occur frequently in northwest China.Vehicle dynamic load is an important factor causing pavement cracking, dislocation and subgrade settlement deformation. The long-term dynamic load exerted by vehicles on the subgrade has caused harm to the normal operation of urban roads and the safety of residents ' travel. On this basis, this paper uses Abaqus numerical analysis software to establish a 3D solid model of the actual road structure system. The indoor shear strength of the actual roadbed soil is tested, and the dynamic response law and settlement deformation characteristics of the loess subgrade under different moisture content, dry density, and vehicle load conditions are examined. Results show that under the action of vehicle load, the vertical strain and vertical displacement of the loess subgrade have an attenuation trend from shallow to deep. The attenuation rate shows a shallow, fast, deep, and slow change mode. The cumulative settlement deformation of the subgrade loess shows a gradual growth trend with the accumulation of cyclic vibration, demonstrating the phenomenon of large deformation in the early stage and stable development in the later stage. The loess structure of the subgrade will become more dense and the strength will be improved after multiple cycle vibrations. Under the action of vehicle load, the sedimentation deformation of loess subgrade increases with the growth of moisture content and load, and decreases with the growth of dry density. The above phenomenon shows that the water content of the loess roadbed can be controlled to effectively reduce the incidence of road disasters such as roadbed deformation and settlement. The research in this paper can provide a reference for the disaster prevention and mitigation of urban roads in the northwest loess area in the future.