Research On Indoor Experimental Model Of Reinforced Dredger Filling By Vacuum Preloading Combined With Dynamic Compaction Method

In recent years,with the rapid development of China’s economic construction,urban construction is changing with each passing day,and land resources are increasingly scarce in coastal areas,which makes largescale land reclamation projects and wharf projects vigorously carried out in China’s coastal zone.The soil of this kind of project site is mostly silt,silty soil and sandy soil with high water content,which must be treated to become available land resources.The vacuum preloading method and the dynamic compaction method are widely used in practical engineering as two soft soil foundation treatment methods.However,due to the "clogging" phenomenon of the drainage board and the soil column effect around the drainage board,the vacuum preloading method is not effective in treating the high water content dredger fill.The dynamic compaction method is suitable for the treatment of soft soil foundations with a certain strength on the surface layer,which is used to transmit impact loads and meet mechanical construction,and cannot be used for direct treatment of newly-filled foundations.This paper intends to use the indoor model research method to explore how to effectively combine the two methods,using the slamming load to alleviate the soil column effect,accelerate the discharge of pore water,and cause the soft soil to be quickly consolidated.The main research results obtained in this paper include:(1)When the vacuum preloading method is used to treat the landfill,the soil column around the drainage board can be appropriately slammed to alleviate the "soil column" effect.(2)Vacuum preloading combined with dynamic compaction method to treat the landfill,the interval of the strong compaction phase can be controlled by the dissipation rate of pore water pressure,and the practicability and economy are higher when the pore water pressure dissipation rate is 80%;The pore water pressure dissipation rate can not be lower than 20%,and below 20% will cause the upper soil to form a “rubber soil” phenomenon and reduce the effect of strong sputum.(3)Vacuum preloading combined with dynamic compaction method to reinforce the foundation of the dredger fill,the initial start of the strong tamping load can be controlled by the settlement rate of the surface before the initial strong shovel,and the vacuum preloading combined with the strong tamping reinforcement is carried out when the sedimentation rate is not more than 1 mm/day.The effect of filling is the best;in order to ensure the reinforcement effect of the soil,the settlement rate is not more than 3mm/day when the concrete is strong.