Large span steel structures are widely used in large-scale engineering construction such as high-speed railway stations, large conference centers, bridges, sports venues, etc. due to their advantages of light weight, large span, good seismic performance, and flexible shape. The installation accuracy directly determines the load-bearing stability, safety, and service life of the structure. Due to the large size, heavy weight, complex spatial shape of large-span steel structural components, and the influence of multiple factors such as construction environment, lifting technology, and temperature changes, the difficulty of controlling installation accuracy is relatively high. If the precision control is not in place, quality hazards such as component misalignment, node connection deviation, and structural deformation are prone to occur. This not only affects the aesthetic appearance of the structure, but may also lead to stress concentration, exacerbate structural damage, and even cause safety accidents.

The connection between railway bridges and tunnels is a key node in railway engineering, connecting two different structural forms of bridges and tunnels. It undertakes the core functions of transmitting loads, adapting to structural deformation, and ensuring smooth driving. It is widely used in railway construction in complex terrains such as mountainous areas and hills. Due to the complex geological conditions, uneven structural stress, limited construction space, and the need to balance the construction accuracy and connection quality of bridges and tunnels, various technical problems are prone to occur during the construction process. If not handled properly, it can lead to quality hazards such as settlement, cracking, and misalignment at the connection site, affecting railway operation safety and structural durability. Based on industry standards and engineering practices such as the "Technical Specifications for Construction of Railway Bridges and Culverts" (JTG/T 3650-2020) and the "Quality Acceptance Standards for Construction of Railway Tunnels" (TB 10417-2018), this article focuses on the core technical difficulties of railway bridge tunnel connection construction, sorts out targeted solutions, and provides professional reference for quality control of railway bridge tunnel connection construction, promoting high-quality construction of railway engineering.

As the core carrier of transportation, highway pavement is subjected to multiple effects such as vehicle loads, temperature changes, rainwater erosion, and geological settlement for a long time. Cracks are one of the most common diseases of pavement. If road cracks are not treated in a timely manner, they can cause rainwater and debris to seep into the interior of the road structure, erode the base and roadbed, exacerbate road damage, cause secondary diseases such as potholes, subsidence, and cracks, reduce road bearing capacity and traffic comfort, shorten the service life of the highway, increase maintenance costs, and even affect traffic operation safety.