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The strength of loess in seasonal frozen soil areas decreases evidently due to the freeze-thaw cycle, which even leads to some engineering and geological problems. Fibre reinforcement is very effective in improving the mechanical properties of soil. Triaxial tests under different water contents, freezing temperatures, and number of freeze-thaw cycles were carried out for fibre-reinforced loess to study the ability of fibre reinforcement to improve the resistance of loess to freeze-thaw damage; scanning electron microscopy (SEM) was also conducted. The effects of freeze and thaw deterioration and reinforcement were discussed by comparing the strength parameters under different test conditions, and the influence mechanism of freezing temperature, number of freeze-thaw cycles, and reinforcement on loess strength was explained. Results show that a lower freezing temperature indicates a more evident decrease in strength after thawing. Under the action of the first five freeze-thaw cycles, the degree of decrease is more prominent. The fibre reinforcement can reduce the fragmentation of aggregates in loess, thereby effectively restraining the deterioration effect of loess during freeze-thaw cycles. Finally, the strength parameter prediction model under different freeze-thaw cycles of reinforced loess is established, thereby providing theoretical support for engineering application and numerical simulation of fibre-reinforced loess. [ABSTRACT FROM AUTHOR]

With the development of ultrahigh voltage transmission line construction in northwest China, an increasing number of overhead transmission lines are crossing the loess regions. Ensuring the stability of electricity transmission towers and mitigating the risk of collapse are crucial prerequisites for the construction of transmission lines. Taking the 750 kV demonstration electricity transmission line in Guanting–Lanzhou East as an example, representative loess samples were selected for compression and collapsing sensitivity tests. Four foundation treatment schemes were designed, and the wetting deformation characteristics were investigated through numerical simulation of the rainfall infiltration process. Corresponding optimisation schemes were proposed. The collapsing process was divided into four stages through laboratory collapsing tests. The relationship function between saturation and the Duncan–Chang model parameters of loess was established, which was introduced into the finite element model to consider the rainfall infiltration process. The analysis of the displacement field, and loess saturation field with time after rainfall infiltration for the four schemes showed that adding a lime-stabilised soil cushion layer and waterproof layer to the inclined column foundation had the best effect. Given that the design scheme needs to consider safety and economy, the thickness of the cushion layer was optimised, thereby reducing the use of lime-stabilised soil by 20%. Research findings provide meaningful guidance for the design of transmission tower foundations in loess areas. [ABSTRACT FROM AUTHOR]

Lightweight is one of the most important research subjects in modern manufacturing. However, the research on lightweight of shell models is rare, and most limited in topological changes. This article proposes a local heat sensor–based lightweight framework of shell models that consists of model analysis, lightweight modeling and analysis, and three-dimensional printing and practical validation in an optimum iterative procedure. Specifically, first, both geometric features and empirical features are introduced to construct a frame structure. Second, a local diffusion–based heat sensor network is exploited to simulate the stress distribution due to two reasons: one is that they have the similar physical transmissibility and the other is that the heat diffusion is smooth, and it guarantees that the thickness variation is smooth and natural without restriction on the degrees of freedom. Then, a local iteration consists of heat simulation and stress analysis is utilized to further improve the efficiency. Finally, we use three-dimensional printer to manufacture testing models and apply them to practical verification and feedback. Our extensive experiments have exhibited many attractive properties, including the flexibility and freedom of the thickness variation, the effectiveness, and credibility of the lightweight. [ABSTRACT FROM AUTHOR]