Abstract: A total of 78 sets of one-dimensional compression data were collected for various types of saturated/unsaturated intact loess(including sandy,silty,and clayey loess). Based on these data,a model was developed to calculate the collapse coefficient using elastoplastic theory. The model incorporates five readily available parameters: initial void ratio,initial water content,vertical stress,void ratio at the liquid limit state,and plasticity index. First,the void ratio,water content,and vertical stress were selected as variables to establish the equation for the saturated/unsaturated compression curve. Second,the compression curves of various loess types were normalized using the void ratio at the liquid limit state,plasticity index,and initial void ratio. Finally,the collapse coefficient was calculated using the established equation via the double-line method. Compared with results from the double-line method(200 data points)and the single-line method(110 data points),the model achieves an accuracy of over 93% in evaluating collapsibility. Quantitatively,the absolute errors for over 90% of the data calculated by the model fall within±0.01,±0.02,and ±0.05 for slight,moderate,and strong collapsibility degrees,respectively. This level of accuracy meets the requirements for quantitative analysis of loess collapsibility in practical engineering applications.