Study on construction deformation prediction and disaster warning of karst slopes based on grey theory

The layout of deformation monitoring points on karst slopes is affected by the thickness of karst overburden soil, dissolution and fragmentation degree, karst development degrees, slope cracking degree, faults or weak interlayers, and other factors. In the study of deformation prediction and disaster warning during karst slope construction, the influencing factors and deformation trend should be comprehensively considered. Based on the error analysis principle and grey theory, grey upper and lower limit prediction models of slope deformation were proposed. These models were applied to the Damao slope, and the probability that the measured cumulative value at each monitoring point remains within the upper and lower grey limits ranged from 61.54 to 100%. The probability at D4, D5, and D11 was low, the probability at the other monitoring points was mostly concentrated between 70 and 90%, and the probability at some monitoring points even reached 100%. Therefore, grey upper and lower limit models are feasible for interval fitting prediction of karst slope deformation data. In addition, based on an empirical equation of the slope sliding limit deformation rate and the grey prediction model, the critical control warning value of slope deformation was obtained, which provides a basis for the quantification of the deformation index of risk evaluation. Through theoretical analysis and field data processing, it was proven that the established grey upper and lower limit prediction models of slope deformation and the critical control warning value of catastrophic deformation are scientific, reasonable, and effective.