The disintegration characteristics of soft rock under water immersion condition are closely associated with various geological hazards.To further investigate the disintegration properties of soft rock,this study focuses on the soft rock of the Pinglu Canal.Indoor soaking disintegration experiments are conducted to observe the disintegration behavior of soft rock at different soaking times and analyze its disintegration patterns.The study incorporated X-ray diffraction (XRD) and scanning electron microscopy (SEM) to examine the mineral composition and microstructure changes of the samples.Additionally,the discrete element method is utilized to simulate the disintegration process of the soft rock and explore its disintegration mechanism.The results indicate that soft rock undergoes significant disintegration in the initial stages of soaking,followed by a deceleration in the disintegration rate.As soaking time extends,the internal pores of the samples gradually enlarge,and changes in mineral composition exacerbate the disintegration.During the disintegration process,friction and collision between particles lead to a rapid increase in kinetic energy,while elastic potential energy also rises due to the deformation of the internal structure.This study reveals the disintegration patterns and microstructure changes of soft rock under water immersion condition.Combined with discrete element modeling,it analyzes the disintegration mechanism,providing some reference for engineering construction in the area.