Development law of shallow karst in a rock slope based on equivalent antimagnetic transient electromagnetic method

The uncertainty and heterogeneity of karst dissolution occurrence space in slope are important factors affecting the stability of rock slope. First, the impact mechanism of karst development on the stability of rock slopes was analyzed from three aspects, that is damage to the integrity of rock structure, changes in hydrogeological conditions, and uneven distribution of rock stress. Then, a rock slope in a site in Shanxi Province was taken as an example. On the basis of the systematic analysis of the engineering geological conditions of the slope, the HPTEM-18 high-precision equivalent antimagnetic transient electromagnetic system was used to design and implement 6 geophysical detection lines with the acquisition frequency of 12.5 Hz, superimposing time of 300, and repeating time of 2. According to the detection and interpretation results, it could be seen that the upper part of the slope was seriously weathered with developed fractures, while the lower part of the slope was relatively intact. Karst phenomena were common in the upper part of the bedrock, and the structural concentrated development zone and water-rich area were not seen. The drilling verification results show that the rock cores in the abnormal area interpreted by geophysical exploration were broken, and the fissures were filled with mud. The sudden drop of drilling indicated that the karst development area interpreted by geophysical exploration was accurate and could meet the requirements of engineering design. The research results could provide important reference and guidance for the stability evaluation of karst developed rock slope of this type.