Abstract: Model tests were carried out in laboratory to get the relationship between the vertical load and the horizontal soil pressure in the surface of soft mucky soil.The thickness of the crust overlying soft mucky soil was less than one fourth of the width of the loaded area.Being limited by the current experimental ability,the horizontal and vertical stresses of one point in ground couldn’t be measured at once.It was the difficulty for the further analysis of the closure effect.PFC software was used to establish mechanical model for the analysis of stress distribution in soft soil during the elastic stage considering the closure effect.Based on the analysis of stress distribution in soft soil during the elastic stage,the stress path method was used to clarify how the critical edge pressure of the two-layered ground was affected by the closure effect.Then it was concluded that K0 in the surface of the soft mucky soil was increased due to the closure effect,so that the development of plastic state of the soft clay was delayed,and the critical edge load of two-layered ground was increased.