Subgrade Settlement Comprehensive Control Technology Research In Soft Soil Area Of Shanghai-Nantong Railway

Soft soil with high water content,high compressibility,low permeability,long consolidation time and other characteristics,attracted researchers' wide attention in the field of special soil.Build subgrades in the soft soil can easily lead to settlement,lack of bearing capacity and other issues,which will bring great harm to a project.There are a lot of soft soil areas along the route of Shanghai-Nantong railway,where the soft soil are distributed became uneven along the depth.A single roadbed settlement control technology is difficult to meet the engineering quality requirements.In this paper,study about comprehensive control technology of roadbed settlement in soft soil area of Shanghai-Nantong railway is carried out by means of geotechnical test,numerical simulation and site subsidence monitoring of soft soil subgrade.First of all,conducted a number of on-site research,selected to take the land,collected the original soil samples shipped to the school laboratory.Through the geotechnical experiment,the basic physical characteristics,deformation and strength characteristics of soft soil were studied.The distribution of soft soil in Taicang area and the physical and mechanical properties of each layer were obtained.The physical properties of the soft soil were measured by the water content and density,the specific gravity of the particles and the limit water content.The compressive coefficient of soft soil was calculated by consolidation test.The shear strength index of soft soil was obtained by direct shear test.The above indicators provided the calculation parameters for the numerical simulation.Then,the finite element software ABAQUS was adopted to simulate the surcharge preloading in the soft soil subgrade of the working point,calculatd the consolidation settlement of soft soil subgrade without re einforcement measure,got the consolidation settlement characteristics and settlement deformation law of soft soil subgrade in this area.Then,the automatic settlement monitoring system was used to monitor the subsidence of the subgrade,and the settlement and deformation law of the soft soil subgrade is obtained;Through the comparison of numerical simulation,artificial observation and the results of automatic settlement monitoring,the treatment effect of settlement control technology of soft soil subgrade is discussed,and the reliability of automatic settlement monitoring data was verified.Given the advice that automatic settlement monitoring system had the characteristics of high precision,large amount of data,real-time data acquisition,which was more conducive to the soft soil subgrade settlement deformation control.At last,this paper had discussed the advantages and disadvantages of different soft foundation treatment methods along the Hutong railway line,and analyzed its applicability in this area.The typical roadbed model under different subsidence control technology is established,and the reinforcement effect of different treatment measures was contrasted from the numerical analysis level,and the rationality of various settlement control methods was demonstrated,which could provide reference for similar engineering construction.