Background <p>Catastrophic issues, such as ecological damages triggered by internal erosion in bare model test within subtropical monsoon climates, are becoming increasingly severe under the combined influence of persistent anthropogenic disturbances and the rapid response of bare model test. However, the mechanisms and critical thresholds governing internal erosion in these settings remain poorly understood, hindering the development of effective long-term prevention and control strategies.</p> Results <p>This study developed natural sample-based synthesis techniques for model test models to establish an optimized ratio parameter system that simulates internal erosion in bare model test under subtropical monsoon conditions. Comprehensive model tests elucidated the patterns of deformation and failure, the dynamics of elemental composition, and the evolution of ecological performance associated with the internal erosion. Furthermore, the study revealed the evolutionary mechanisms and defined the critical state thresholds for internal erosion in these settings.</p> Conclusions <p>The geologically accurate reconstruction of the physico-mechanical properties of bare model test affected by internal erosion within subtropical monsoon climates was achieved. This work provides a theoretical foundation for analyzing the causes of related hazards and for developing targeted prevention and control measures.</p>