Research On The Application Of Vacuum Combined Surcharge Preloading In The Treatment Of Deep Soft Soil Foundation

With the rapid economic development,the speed of infrastructure construction in China’s coastal areas has increased rapidly.However,large areas of soft foundation are widely distributed in coastal areas.The soil has a high water content,high compressibility,and difficult to consolidate.The foundation has shortcomings such as poor stability,which in turn affects the stability of the engineering structure,which brings great harm to the construction of the construction and pavement construction.The vacuum combined surcharge preloading has numerous advantages such as easy construction,low cost,low noise and short construction period.Under the combined effect of surcharge and vacuum pressure,the soft foundation can quickly consolidate.The main settlement can be completed in the construction,which greatly reduces the post-construction settlement,so it is widely used in the treatment of soft soil foundation in coastal areas.Based on previous research results,this paper summarizes and analyzes the reinforcement principle,calculation method,monitoring method,and index results of the vacuum combined surcharge preloading based on a large-scale field test.Comparing with the finite element analysis results,this paper explores the relevant construction parameters of vacuum combined surcharge preloading.The main research content and results are as follows:(1)The similarities and differences between the vacuum preloading and the surcharge preloading are compared and analyzed.The characteristics of the two methods in the reinforcement mechanism,stress path and strength growth are compared and analyzed.Based on this,the vacuum combined surcharge preloading is analyzed.The mechanism of reinforcing soft foundation by vacuum combined surcharge preloading is studied and analyzed.The vacuum combined surcharge preloading can achieve the offset of the positive and negative pore pressure,and help to promote the rapid consolidation,which helps shorten the construction period.(2)By summarizing and analyzing field test data,the development of vacuum degree,pore water pressure and surface settlement during the test process were analyzed.The reinforcement mechanism of vacuum combined surcharge preloading was revealed,and the mechanical properties of soil before and after reinforcement were compared.The obvious improvement of the strength and stability of the deep soil has verified the advantages of the vacuum combined surcharge preloading in the reinforcement of deep soft ground.(3)The numerical simulation is used to simulate the vacuum combined surcharge preloading,and the results of the numerical simulation are compared with the field monitoring results to verify the consistency.The influences of the construction parameters such as permeability coefficient,drainage board arrangement and vacuum pressure distribution were investigated,and corresponding optimization suggestions were proposed.