Bayer red mud (RM)-based geopolymers are economical and ecofriendly alternatives to cement because of their superior performance. This study investigated alkali-activated cementitious materials by combining RM, fly ash (FA) and slag, and the mixtures were used to produce ecofriendly composites. The influence of the Si/Al molar ratio (3.30–3.79) on the initial properties (setting time and flowability) and hardened properties (compressive strength, drying shrinkage and water permeability) of the composite materials was studied. The Na₂O content was fixed at 4 wt%, and the thermal activation temperature was 800 °C. The phase evolution and geopolymerization mechanism of the effect of the initial Si/Al molar ratio on the material properties was investigated by FTIR, XRD, TG–DTG and SEM–EDS. The results of M1.2Si333 indicated that the compressive strength of the blends can reach 33.5 MPa at 28 days, with a drying shrinkage rate of 1.20%. Compressive strength decreases, while drying shrinkage increases with a higher initial Si/Al ratio. Microstructural analyses revealed that a low Si/Al ratio and alkali activator modulus enhance the dissolution of precursors to form C–(A)–S–H gels, which increase the compressive strength. The results promoted the application of RM-based geopolymer-engineered cementitious composite and enhanced the resource efficiency of the bauxite residue.

Engineering geological conditions in our country are complex and diverse. Many high-rise buildings, bridges, and launch towers are inevitably built on high and steep slopes. Heavy rain, earthquake, human engineering activities, and other factors lead to frequent landslides, soil creep deformation, and overall sliding, resulting in a certain bending moment and flexural deformation of foundation piles, may cause damage to the substructure and foundation pile failure, and then endanger the safety of the superstructure. In the past, bridge pile group foundation was used in bridge pile foundation engineering to improve the impact situation, but the stress environment of bridge pile foundation in landslide is obviously different from that of bridge pile foundation in the flat area. The large deformation of soil in front of the pile will easily cause the phenomenon of soil sliding and peeling, which will increase the technical difficulty of antislide pile construction. Based on this, this study firstly briefly introduces the relevant theories and technologies of railway landslide antislide pile technology and then establishes the static model of railway landslide antislide piles with different nanomaterials. Finally, the reinforcement technology of different nanomaterial antislide piles for railway landslide is expounded, which can provide guarantee for the application of different nanomaterial antislide piles for railway landslide. The results show that the preloading is carried out according to 1/10 of the design load to reduce the void between the soils. After the load is maintained for 2 hours, the load is unloaded to 0, and good skid resistance can be obtained.

This paper investigates earth pressure and load transfer of a novel Surrounding Pile Soil Coupling–Anti-slide Chord (SPSC-AC) structure for railway slope reinforcement under dynamic train loading through physical model experiments. The study systematically analyzes the synergistic effects of the connecting beam rise-to-span ratio (f/L) and anchoring ratio (η) on the structural load redistribution mechanism and pile–soil interaction. The results show that the SPSC-AC structure forms a three-dimensional (3-D) soil arch via the curved connecting beams. The inter-row earth pressure follows a pattern of rear row > middle row > front row, while the earth pressure on corner piles exhibits a reverse increase owing to the soil arching effect. The rear pile thrust sharing ratio δ (0.58–0.68) and the pile–soil stress ratio n (1.16–1.37) are defined as two key performance parameters reflecting load distribution efficiency, and quantitative δ–f/L and δ–η relationships are established. The bending moment distribution along the pile body corresponds closely with the earth pressure pattern. Based on these results, the present study proposes optimal parameter ranges (f/L ∈ [1/4, 1/3] and η ∈ [5/11, 7/13]) along with recommendations for corner pile strengthening and differential stiffness design. These findings provide a theoretical basis for optimal anti-slide structure design.