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In recent years, highway infrastructure in the Ningxia region of China has rapidly advanced. Cement–loess is extensively utilized in the roadbed and foundation reinforcement. It is necessary to conduct micro–macro-analysis and model derivation of the electrical resistivity on Ningxia cement–loess, which are beneficial for both the practical application of electrical resistivity and the evaluation of the geotechnical properties of cement–loess. Therefore, a series of electrical resistivity measurements, microstructural observations (scanning electron microscopy), mineral analyses (thermogravimetric analysis), and theoretical analyses were adopted on the cement–loess. The following conclusions can be drawn: The electrical resistivity is negatively related to dry density and water content, while it is positively related to cement dosage and curing age. A cement dosage of 6% exhibits a lower hydration reaction potential compared to 12%, causing a slower increase in electrical resistivity. The formation of calcium silicate gel around particles results in particle clustering and pore filling, reducing the pore area and increasing electrical resistivity. Increased hydration also decreases microscopic orientation, contributing to a higher electrical resistivity of cement–loess. Finally, a new three-dimensional electrical resistivity model was created, finding that the electrical resistivity of Ningxia cement–loess was determined by the dry density, water content (ρd·w), cement dosage, and curing age (aw·T) in an exponential function form. The new three-dimensional electrical resistivity model could be used in the high-efficiency evaluation of the cement–loess geotechnical parameter, offering valuable insights for the monitoring and maintenance of road infrastructure. [ABSTRACT FROM AUTHOR]

Understanding the primary and secondary relations of influencing factors is crucial for predicting deformation and controlling collapse in cutting slopes. Using a cutting slope along the Shuangcheng to Dalijia expressway in Gansu Province as the research object, this research utilized the FLAC3D finite element software platform to establish dynamic correlations between saturation, gravity, and soil shear strength through FISH language. Based on this, safety factors of the cutting slope were calculated under different rainfall intensities, slope ratios, and rainfall duration. Grey relational theory was applied to determine the primary and secondary relationships of key factors affecting shallow collapse of cutting slopes under rainfall conditions. Indoor rainfall experiments and on-site ecological protection tests were conducted to summarize the shallow collapse mechanism and propose the environmental control measures. The study revealed that the failure mode of cutting slopes transitioned from deep overall sliding to shallow local sliding during rainfall. As the slope ratio decreased, the shallow collapse area gradually shifted from the slope shoulder to the foot of the cutting slope. Cumulative erosion rates of shallow soil in cutting slopes decreased initially and then increased over time during rainfall. Installing arch skeletons and reducing the slope ratio enhanced the cutting slope's resistance against shallow collapses. Among with the protective materials, polypropylene fiber-reinforced soil protective materials exhibited the best timeliness and ecological control effect for shallow collapses of cutting slopes compared to HP-FGM and EFM materials. [ABSTRACT FROM AUTHOR]