Experimental and Numerical Investigation of the Disintegration Behavior of Remolded Lishi Loess Under Different Initial Water Contents

With the implementation of the Western Development Strategy and the Belt and Road Initiative, engineering activities on the Loess Plateau have expanded substantially in both scale and depth. Consequently, the disintegration of Lishi loess, which has received relatively limited attention, has become an increasingly important concern in relation to geological hazards and engineering stability. This study investigated the disintegration behavior of remolded Lishi loess specimens with different initial water contents under controlled dry-density conditions and developed a mathematical model to characterize the disintegration process. In addition, three-dimensional particle flow code (PFC3D) simulations were performed to provide a particle-scale mechanical interpretation of the observed behavior. The experimental results showed that the disintegration curves of the specimens exhibited a typical asymmetric S shape at all tested initial water contents. The Gompertz model provided a compact empirical description of these curves, with coefficients of determination ranging from 0.993 to 0.999. In the model, α denotes the upper asymptote of the disintegration curve, λ characterizes the growth-rate behavior, and β represents the characteristic time associated with the inflection point. These parameters should be interpreted as empirical descriptors of the disintegration process rather than direct measures of the microscopic properties of loess. Although the model closely reproduced the experimental curves, further validation using independent datasets is required before it can be applied predictively to other specimens or test conditions. The PFC3D simulations provided an equivalent mesoscopic representation of contact-network weakening, bond breakage, and progressive particle detachment at different initial water contents. The simulated evolution qualitatively reproduced the progression from boundary-particle detachment to the gradual loss of specimen integrity and final particle accumulation. These findings characterize the water-content-dependent disintegration behavior of remolded Lishi loess and provide a preliminary basis for understanding the water sensitivity of disturbed or reworked Lishi loess in engineering applications.