Particle initiation is the foundation of cuttings transport research, and existing critical velocity models have room for improvement in cuttings bed scenarios. This paper analyzes the mechanical equilibrium of particles under critical conditions, proposes a new mechanical model for cuttings transport, establishes an iterative model for cuttings bed thickness, and investigates the laws of cuttings transport patterns based on particle initiation. The study finds: (1) When the drill pipe does not contact the cuttings bed, the dimensionless cuttings bed height is approximately 1.15, and the cuttings bed thickness is significantly influenced by the interaction between well inclination angle and transport patterns. (2) During partial contact, the drilling fluid flow field becomes turbulent due to local interference from the drill pipe, leading to differentiated responses in cuttings bed accumulation under different transport patterns, resulting in curve mutations. (3) When the drill pipe is fully submerged in the cuttings bed, the dimensionless cuttings bed thickness is approximately 1.6. In highly deviated well sections, the efficiency of the lifting mode is limited, and the cuttings bed thickness gradually becomes independent of transport patterns, instead being determined by wellbore geometry and total cuttings volume. These findings provide important guidance for predicting cuttings bed height and studying the laws of cuttings transport patterns.