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To study the deformation and settlement characteristics of tunnel lining structures, a tunnel lining structure model was designed based on distributed fibre optic sensing technology. Compared to the cylindrical model used in traditional tunnel lining structural model experiments, in this study, a reinforced concrete structural model was adopted, which can embed fibre optics in the structure, which is closer to actual tunnel engineering conditions. Central and symmetrical concentrated loading experiments were carried out with a simply supported reaction frame. The results of the distributed fibre optic monitoring were compared and analysed with those of traditional monitoring methods to verify the reliability of the distributed fibre optic monitoring results. The numerical simulations of the experiments were conducted by using finite element analysis. By comparing and analysing the simulation and experimental results, the correctness of the simulation calculation results were verified. On this basis, the impact of concrete strength, circumferential reinforcement spacing, and longitudinal reinforcement strength on the deformation and settlement of the tunnel lining structure were analysed. The results show that the hierarchical effect of the strain monitoring results obtained by the embedded fibre optic is more obvious, indicating that the radial monitoring effect of the embedded fibre optic on the tunnel structure is less affected by other external factors than the strain gauge, and the monitoring data are more accurate and effective, with good engineering characteristics. Improving the concrete strength, appropriate circumferential reinforcement spacing, and increasing the longitudinal reinforcement strength can effectively enhance the ability of the structure to resist deformation at the stress location. These factors play a significant role in improving the overall resistance to deformation and safety of the structure. The research results provide a theoretical basis and experimental data for the application of distributed fibre optics in monitoring the deformation and settlement of tunnel lining structures. [ABSTRACT FROM AUTHOR]

In this study, the dynamic process of soil landslides is investigated using the material point method (MPM). A basal friction algorithm is developed based on the MPM, and the pore water pressure is considered for calculating the basal friction. A large‐scale debris flow experiment is performed to validate the effectiveness of the MPM in simulating the dynamic process of soil landslides. The calculated depths of the debris flow using the MPM are consistent with the experimental results. The effects of the basal friction angle and internal friction angle on the debris flow depths are discussed. Moreover, a landslide case is simulated using the MPM, and the calculation results are consistent with the measured results. The horizontal velocity, vertical velocity, velocity direction, and kinetic energy of the landslide are analyzed. Finally, a case involving a different slope near a landslide is evaluated using the MPM. The distributions of velocity in different directions and changes in the average velocity, kinetic energy, and sliding distance are analyzed. By setting a retaining wall, the accumulation height of a landslide accumulated at the retaining wall and the normal force on the retaining wall can be estimated. [ABSTRACT FROM AUTHOR]

The Wufengshan Yangtze River Bridge, a thousand-meter scale high-speed railway suspension bridge, is located in Zhenjiang, Jiangsu Province, China. The construction of the bridge surpasses the technological limits of the thousand-meter scale railway bridge. To accomplish this feat, a new type of plate-truss steel beam was adopted for the first time, along with a full penetration welding method employed between the U-rib and the top deck. These innovative methods fill the gaps in high-speed railway suspension bridge construction technology in China and the world. This paper describes the design method, calculation theory, and the corresponding technical standards of high-speed railway suspension bridges in China, which together provide the information necessary for the construction of the subsequent bridges. [ABSTRACT FROM AUTHOR]

Crushing fresh waste concrete that collects from ready‐mixed concrete plants to prepare aggregates for new concrete production reduces the carbon dioxide footprint. This study intends to predict the mechanical properties of recycled concrete with fresh concrete waste aggregate (FCWA), including compressive strength development over time, elastic modulus, and shrinkage. Current available experimental studies were first summarized to investigate the impact of FCWA incorporation on the mechanical properties of resulting concrete. Prediction expressions were proposed for compressive strength development over time for recycled concrete accounting for FCWA replacement (r) ratio. Elastic modulus and shrinkage prediction models were theoretically derived for recycled concrete accounting for the residual cement paste content (CRCP) of FCWA and benchmarked against available experimental results. Results showed that concrete decreased its mechanical properties with increasing FCWA r ratio. 35.7‐58.7% reductions in the compressive strength and 36–55% reductions in the elastic modulus for FCWA concrete could be observed, while 66–108% increases in the shrinkage could be obtained for concrete with FCWA r ratio of 30%. The models proposed in this study well predicted the mechanical properties for FCWA concrete. [ABSTRACT FROM AUTHOR]