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With the increase in the mileage of high‐speed railways around the world, subgrade problems related to the same have been emerging in large numbers. In view of the shortcomings of slow construction speed and large disturbance caused by conventional anti‐slide piles during emergency reinforcement of subgrades, an “arch–chord coupled anti‐slide structure” is proposed in this study, based on the three‐dimensional characteristics of the subgrade creep, and its anti‐slide mechanism is analyzed; furthermore, a theoretical calculation method for the same is proposed. The results show that the arch–chord coupled anti‐sliding structure can form a coupled body containing multiple surrounded piles when subjected to thrust, thus offering a pile–soil composite structure similar to a retaining wall. This results in a large anti‐sliding force. By setting a virtual pile to regularize the layout of the structural pile, the pile internal force can be accurately computed. The findings of this study provide a theoretical basis for the analysis and design of coupled anti‐sliding structures in future.

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Although vegetation is increasingly used to mitigate landslide risks, how vegetation roots affect the landslide threshold of slope has rarely been explored, particularly in the case of lateral runoff. In this study, we established a two-dimensional saturated-unsaturated infiltration equation considering the hydraulic effects of vegetation roots. The analytical solution for the shallow unsaturated two-dimensional coupled infiltration of vegetated slope (VS) was obtained by a Fourier transform technique. The numerical method was used to evaluate the stability of VS caused by four root architectures, the rainfall amount, and the rainfall duration. Subsequently, the transformation law in runoff, vegetation evaporation, and landslide threshold was analyzed. The results indicate that the factor of safety (FOS) increases with increasing drying time and decreases with increasing depth; the minimum FOS is at the junction of the root-rootless zone. Runoff and vegetation evaporation are favorable for the shallow stability of VS. The time of the safe area is 35 h for rainfall amount 500 m in the uniformly root clay slope. Moreover, four landslide threshold curves that reflected the root architecture, rainfall amount, and rainfall duration are developed, which are more realistic than those created using one-dimensional instability modeling.

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Strength of vegetated coal-bearing soil is of great significance to evaluate the shallow stability of vegetated slopes in coal-bearing soil regions. This paper takes D-W cycles, dry density, water content, and vegetation root (VR) content as four factors and carries out the triaxial test for the orthogonal design of vegetated coal-bearing soil in southern China. The strength curves of vegetated coal-bearing soil under four factors were obtained. The Taguchi method was used to quantitatively analyse the effects of four factors. The microstructure of coal-bearing soil under D-W cycles and the theory of soil reinforcement by VR were discussed. The results indicated that D-W cycles had a significant effect on the cohesion and internal friction angle ( P < 0.05 ). The internal friction angle was little affected by the water content and VR content, which had considerable influence on the cohesion. The cohesion could be improved with less than 2% VR content. The cohesion was the largest for no D-W cycles, 10% water content, and 2% VR content. The links between mineral particles go from a stable layered structure to unsteadiness chain structure with the increase in the number of D-W cycles.