As a kind of important engineering material, steel fiber‐reinforced concrete was used widely in civil engineering. Up to now, steel fiber‐reinforced concrete was usually produced by the traditional mixing method. For the reason of uniform distribution of fiber, the reinforcement of mechanical properties of concrete was inadequately performed. In this paper, C50 steel fiber‐reinforced concrete and C60 steel fiber‐reinforced concrete were manufactured by traditional mixing and vibratory mixing methods, respectively, and then, the cube compression test, flexural test, splitting tensile test, and the bending test were carried out. The reinforcement effects of mechanical properties were analyzed by comparing the traditional mixing and vibratory mixing methods. The results show that vibratory mixing can effectively improve the distribution of steel fibers in concrete and can increase the density of steel fiber concrete, and therefore, it effectively improves the mechanical properties of steel fiber‐reinforced concrete when compared to the traditional mixing method.

The polymer antiseepage wall is a new technology for the reinforcement of earth dams. It has the advantages of being efficient, ultrathin, minimally invasive, and economical, which makes it even more popular and widespread in many applications. However, research on the seismic response of the polymer antiseepage wall is lacking. Because most earth dams are damaged by seismic loads and the antiseepage system is the weakest part, the related dynamic studies are of great significance for this new type of polymer antiseepage wall. In this study, two physical centrifuge models manufactured with prototype materials were used to investigate the seismic response characteristics of a prototype structure. The results of the seismic response characteristics of the earth dam with a polymer antiseepage wall are presented, along with a comparison of the response characteristics for earth dams with a concrete core. The results show that the earth dam with a polymer antiseepage wall had a good capacity for seismic damage resistance.

This work addresses how vibration stirring, steel-fiber volume ratio, and matrix strength affect the mechanical properties of steel-fiber-reinforced concrete. The goal of the work is to improve the homogeneity of steel-fiber-reinforced concrete, which is done by comparing the mechanical properties of steel-fiber-reinforced concrete fabricated by ordinary stirring with that fabricated by vibration stirring. The results show that the mechanical properties of steel-fiber-reinforced concrete produced by vibration mixing are better than those produced by ordinary mixing. The general trend is that the mechanical properties of steel-fiber concrete have a linear relationship with the matrix strength and the volume ratio of steel fiber. The best mechanical properties are obtained for a steel-fiber volume ratio of less than 1%. We have also established calculation models for the mechanical performance index of vibration, mixing steel-fiber concrete based on the test results. Microscopic studies show that vibration stirring optimizes the microstructure of the transition zone between the concrete interface and the slurry, and improves the homogeneity of the steel-fiber-reinforced concrete, and enhances the adhesion between the mixture components.

The application of polymer grouting in underground pipeline rehabilitation is increasing gradually. The leakage and subsidence of buried pipelines could be repaired by polymer grouting technology. In order to analyse the calculation theory of the pipeline repairing process, the Winkler model and the Vlazov model of the pipe‐soil‐polymer interaction based on the elastoplastic theory are established, the calculation formulas of the pipe‐soil interaction under polymer grouting are derived, and the MATLAB calculation program based on the transfer matrix method is compiled. Then the calculated values are compared with the pipeline experimental values, and the influence of different factors on the internal force and deformation of the polymer‐repaired pipeline under different work conditions is discussed. The results show that the values and trends of the pipe deformation and circumferential bending moment calculated by the models are consistent with the experimental results, and the results obtained by the Vlazov model are closer to the experimental values. In addition, the void at the bottom of the pipeline has a large impact on the mechanical properties of the pipeline. However, polymer grouting can repair disengaged pipelines effectively and restore their mechanical properties. The proposed methods and calculation results are valuable for pipeline polymer repairing analysis and pipeline void repairing design.

As a common water conveyance structure, aqueduct is widely used in cross‐regional water conveyance and diversion projects. However, large double‐trough aqueduct structures are prone to damage under earthquake, resulting in water leakage and even interruption, endangering the safety of people’s lives and property in surrounding areas. In this paper, the nonlinear reinforced‐concrete material program is compiled based on the FORTRAN language. Taking the Shuangji River aqueduct project as an example, the numerical model of the fiber beam element of the double‐trough aqueduct structure is established, and the nonlinear dynamic time‐history response analysis of different ground motion inputs is carried out. Based on the midspan displacement and acceleration time history, pier bottom bending moment and shear force time history, the nonlinear response law of large aqueduct structure is studied. A criterion for determining the overall collapse of aqueduct structure based on effective energy is proposed. The correctness and feasibility of the nonlinear numerical model of the aqueduct structure and the dynamic catastrophe analysis method are verified by focusing on the overall seismic response of the aqueduct structure and the material yield status of key parts, and comparing with the collapse criterion based on the limit value of pier top displacement angle. The conclusions will provide a basis for seismic analysis, optimization design, and operation and maintenance safety assessment of large aqueduct structures and have important theoretical significance and engineering application value.