In order to improve the ability of the flexible support structure to resist, recover and adapt to the failure of expansive soil slope, it is necessary to analyze and study its structural resilience systematically. Based on the long-term field monitoring test of expansive soil slope with flexible support along the south line of the Guinan key project, combined with the whole life cycle assessment (LCA), this paper discusses the theory and method of resilient design of expansive soil slope with a flexible support structure. The results show that the variation trend of geogrid strain is basically consistent with that of soil pressure at the side of the slope. It increases gradually with the increase in rainfall in the rainy season. When the rainfall decreases significantly in the dry season, the geogrid will shrink accordingly to realize the periodic regulation of lateral deformation of expansive soil. The life cycle assessment analysis shows that the carbon emission of the flexible support structure is 10% of that of the rigid support structure, and the resource and energy consumption of the flexible support structure is about 50% lower than that of the rigid support structure.

Expansive soils exhibit directionally dependent swelling that traditional isotropic models fail to capture. This study investigates the anisotropic swelling characteristics of expansive soil with a medium swelling potential through the use of modified oedometric testing. Vertical swelling strains can reach up to 1.71 times that of the horizontal movements, confirming intrinsic anisotropy. A nonlinear elastic constitutive model incorporates vertical and horizontal elastic moduli with respect to matric suction to characterize anisotropy. Three elastic parameters were determined through the experiments, and predictive equations were developed to estimate the unsaturated moduli. The constitutive model and predictive techniques provide practical tools to better assess expansive soil pressures considering anisotropy, offering guidelines for utilization and design. The outcomes advance understanding of these soils’ directionally dependent behavior and stress–strain–suction response.

The distribution of seepage field in embankment dams is an important aspect of the safe operation of in-service embankment dams. The distributed optical fiber temperature monitoring technology has some advantages of high sensitivity, strong real-time performance, and rich data. This is a problem worthy of study for the monitoring of seepage field in embankment dams. This paper takes a certain embankment dam as an example. It sets up some optical fiber temperature measurement sections near the traditional seepage monitoring section. It elaborately introduces the optical fiber layout, on-site construction, long-term monitoring, and simulation. The result shows that the position of the infiltration line can be measured by using heated distributed optical fibers; the error is within the range of 0.1 to 0.2 m. The monitoring results are basically consistent with the traditional seepage monitoring results, indicating that it is feasible to use distributed optical fiber temperature measurement technology for dam seepage monitoring. Long-term monitoring and numerical simulation have obtained the infiltration lines, velocity vectors, and streamlines at different water levels, verifying the reliability of the distributed optical fiber temperature monitoring technology. As summarized, the distributed optical fiber temperature measurement technology can accurately obtain the seepage information inside the dam body, providing a new idea for the analysis and safety assessment of the seepage field of embankment dams.

The pile foundations of hydraulic crossing structures are vulnerable to scour, which can significantly reduce bearing capacity and threaten structural safety. In existing studies, simplified assessment approaches have mainly been used, such as pre-defined scour holes or instantaneous scour, which cannot fully capture the progressive development of scour holes. In addition, there are limited systematic comparisons of the lateral responses of piles with different cross-sectional shapes under scour conditions. To address these issues, a series of finite element simulations were carried out in this study and the numerical model was validated against centrifuge test results. The “model change” technique was then used to simulate the progressive development of general scour. Circular and square piles with equal cross-sectional areas were considered under scour conditions, and the effects of instantaneous and progressive scour were compared at the same depth. The load–displacement response, pile–soil deformation and failure mode, bending moment, and pile displacement were analysed, with the results showing that square piles exhibited a higher lateral bearing capacity than circular under both no-scour and two types of general scour conditions. Scour altered the pile–soil failure mode and reduced the extent of the wedge-shaped failure zone around the pile, with that induced by square piles being larger than that induced by circular. At the same scour depth, the difference between the effects of instantaneous and progressive scour on lateral bearing capacity was not significant. The results indicate that the pile cross-sectional shape is a key factor affecting scour resistance and that square piles show a relative advantage. The findings provide useful guidance for the cross-sectional selection and lateral bearing capacity assessment of pile foundations in scour-prone areas.