Due to the seasonal permafrost thawing, the Qinghai–Tibet Highway has a depression and instability of the roadbed. In order to obtain the ablation interface and water content characteristics of seasonal permafrost areas, non-destructive ground penetrating radars using electromagnetic wave detection methods are widely used. Regarding the imaging of the ablation interface in permafrost regions, this paper proposes a high-precision procedure for seasonal permafrost media using waveform difference analysis, electromagnetic wave attenuation attribute calculation and relative wave impedance conversion. It improves the resolution and division accuracy of the imaging. In addition, the study demonstrates a method to calculate the temperature and water content of the ablation zone by mining attenuation attribute, relative wave impedance attribute, absolute instantaneous amplitude attribute and the weighted average frequency attribute parameters under the constraints of the measured data. This method has high accuracy and high efficiency and can be used in the rapid calculation of temperature and water content of seasonal permafrost on the Qinghai–Tibet Highway.

Air-boosted vacuum preloading, composed of anticlogging vertical drains and an outer booster system, is a new foundation treatment method that is beneficial to accelerating soil consolidation by applying different pressures between soil and vertical drains. Based on the assumption of equal strain, the present paper has simplified the calculation model of the air-boosted vacuum preloading method. Combined with the Newman-Carroll equation, the analytical solution for the consolidation of the double-layer soil foundation is proposed using separation of variables. Moreover, the theoretical solutions of consolidation without well resistance and ideal wells were given, and a chart convenient for engineering practice was acquired. Results show that the setting of well diameter ratio should not be more than 10 in engineering practice. At present, the consolidation theory of air-boosted vacuum preloading is imperfect and only focuses on the reinforcement mechanism of single-layer foundation. Therefore, it is of great significance to perfect the consolidation theory of air-boosted vacuum preloading with multiple layers.

In recent years, a series of leakage accidents have been caused by the destruction of water leakage of water supply pipelines in urban areas. In order to determine the leakage characteristics of underground pipelines, GeoStudio was used to simulate the leakage areas in different pipeline diameters. Based on the finite difference method and the Maxwell equation of the electromagnetic wave propagation, signal characteristics of the ground penetrating radar (GPR) wave were analyzed for different ground conditions through forward simulation. Additionally, the properties of the data were analyzed by applying the technology of trace integration and frequency dividing on S-transform to fully determine the location and extent of the leakage. The correctness of the forward simulation results as well as the validity of attribute analysis were verified by field experiments where the different characteristics of morphological and moisture content distribution are proposed in different soils, pipeline diameters, and damage points. The relationship between soil moisture content and dielectric constant showed a three-dimensional function through Topp model, thereby establishing a standard electromagnetic wave reflection of the GPR for pipeline leakage. The trace integration and frequency dividing on S-transformation are used to improve the accuracy of detection. The results would provide a reference for an accurate evaluation of pipeline leakage in the future.

Horizontal frost damage is a significant hazard threatening the safety of structures in cold regions. The frozen fringe represents the transitional zone between unfrozen and frozen soil. Its formation and migration not only directly influence the distribution of water during freezing but also play a significant role in the frost heave behavior. This study employed self-developed horizontal frost heave equipment to conduct seven experiments, exploring the effects of initial water content and dry density on the development of the frozen fringe in kaolin clay. As the initial water content increases, the water migration speed accelerates, and frost heave increases. The experimental results show that for every 5% increase in initial water content, the frost heave increases by an average of 3.43 mm. With increasing initial dry density, frost heave decreases, and the water migration speed decreases. For every 0.1 g/cm³ increase in initial dry density, the frost heave increases by an average of 3.26 mm. The study also found that the frozen fringe does not strictly advance in the vertical direction, which may have a potential impact on the structural integrity. Based on these experimental results, this study proposes an improved method for predicting the frozen fringe using the freezing point, building upon the Mizoguchi model, and validates its accuracy with field data. The research provides a theoretical basis for the design of slopes, retaining walls, and foundation pits, as well as for the implementation of frost heave prevention measures in cold regions.