The fine particles deposition/detachment process under liquid flow shear shock or forced periodic operation conditions in a high pressure/temperature trickle-bed reactor was analyzed theoretically using a dynamic multiphase flow deep-bed filtration model. The model incorporates physical effects associated with detachment of the fine particles from the collector surface as a result of colloidal forces in the case of Brownian particles or by the hydrodynamic forces for non-Brownian particles. An important finding of the work was that for non-colloidal fine particles, forced periodic operation procured improvements (assessed in terms of reduction in specific deposit and pressure drop) in the mitigation of plugging in trickle-bed reactors. However, due to the highest critical shear stress values for fine particles in the colloidal range, forced periodic operation did not substantiate useful practical effect. In the circumstances when Brownian fine particles are involved, reduction of plugging may take place under liquid flow shock conditions. (c) 2005 Elsevier Ltd. All rights reserved.