Damage Evolution Analysis of Loess Slope under Dynamic Compaction Based on the Multielectrode Resistivity Method

Under continuous dynamic compaction and vibration, slope instability and failure in the Loess Plateau region may occur. Many previous studies focused on the overall stability of the slope, but the damage mechanism of the loess slope seldom discussed. To analyze the cause and degree of loess slope damage under dynamic compaction, this paper proposes the basis of judging slope soil damage by analyzing its porosity–resistivity relationship. Unlike previous studies focusing on postfailure analysis or overall stability, this study proposes a nondestructive, in situ method to quantify progressive internal damage during the compaction process itself. Combined with the field test, the soil mass of two different loess slopes in the field was tested by the multielectrode resistivity method, and the change in internal resistivity of slope soil before and after dynamic compaction was analyzed. The results revealed that the damage degree of different parts of a slope caused by different tamping positions is different. The resistivity of slope soil can reflect the degree of soil damage and deterioration. The resistivity of some measuring points decreases in the early period of dynamic compaction, because the fine particles in the soil gradually fill the pore space under vibration, and the density of soil particles increases. Under continuous dynamic compaction, the resistivity of the particles inside the slope increases gradually, and the damage and deterioration degree of the soil is greater than zero. This level of deterioration indicates significant structural weakening that may precipitate failure under subsequent environmental loading. According to the test results, the maximum damage and deterioration degree of slope soil can reach 27%. The pore volume of the soil increases, the cohesiveness weakens, the cement between the soil particles gradually breaks, and the damage in the slope is intensified, which further reduces the stability of the slope soil. Compared to intrusive methods, the high-density electrical method provides a rapid, spatial assessment of subsurface damage, offering real-time guidance for optimizing construction sequencing and mitigating slope instability.