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.

Modal parameters are important parameters for the dynamic response analysis of structures. An output-only modal parameter identification technique based on Hilbert Vibration Decomposition (HVD) is developed herein for structural modal parameter identification to (1) obtain the Free Decay Response (FDR) of a structure through free vibration or ambient vibration tests, (2) decompose the FDR into modal responses using HVD, and (3) calculate the instantaneous frequencies and instantaneous damping ratios of the modal responses to obtain the modal frequencies and modal damping ratios. A series of numerical examples are examined to demonstrate the efficiency and highlight the superiorities of the proposed method relative to the empirical model decomposition-based (EMD-based) method. The robustness of the proposed method to noises is also investigated and proved to be positive effect. The proposed method is proved to be efficient in modal parameter identification for both linear and nonlinear systems, with better frequency resolution, and it can be applied to systems with closely spaced modes and low-energy mode.

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Arch‐chord coupled anti‐sliding structure is a new type of anti‐sliding structure composed of multiple single piles in a specific form. The coupling effect of pile and soil is the most important key point. In this article, the factors that affect the coupling bearing capacity and load sharing ratio of the arch‐chord coupled anti‐sliding structure are screened out, and the rule that the evaluation index is affected by each factor is analyzed. The results show that, with the increase of pile diameter, the value of structural coupling ultimate bearing capacity increases exponentially, but the growth rate slows down gradually. With the increase of pile spacing, the value of structural coupling ultimate bearing capacity decreases. With the increase of soil cohesion around the pile, the value of structural coupling ultimate bearing capacity increases linearly. The coupling ultimate bearing capacity and load sharing ratio of the anti‐sliding structure are the most sensitive to the change of the internal friction angle of the soil around the pile, and the pile diameter has little effect on the evaluation indexes.

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