Analysis Of Settlement Characteristics Of Soft Soil Foundation Under Wide Embankment Loading

Soft soil is widely distributed in China.Due to its special engineering properties,it is necessary to focus on the settlement and deformation of soft land embankment.With the increasing traffic volume,the construction of wide embankment is increasing day by day.Wide embankment covers a wide area and has a large amount of filling,which will lead to serious consequences if it is not designed properly.Therefore,it has prominent theoretical significance and application value to study the settlement and deformation characteristics of soft soil foundation wide embankment and then take targeted engineering countermeasures.Based on the settlement characteristics of soft soil foundation under the load of wide embankment,this paper mainly carried out the following work:（1）Through literature research and engineering research,typical cases of new wide embankment projects in soft soil foundation of highway,railway,subway,airport and other industries at home and abroad were sorted out,and settlement characteristics of these projects obtained through field observation and centrifugal model test were investigated.The settlement of soft soil foundation of wide embankment is significantly different from that of narrow embankment.The settlement of soft soil foundation of wide embankment presents obvious"saddle"type at the center line of embankment,while the settlement of narrow embankment foundation surface presents typical"bended basin"type.（2）The evaluation method,index and standard of new wide embankment for soft soil foundation are analyzed.The characteristics of these methods,indexes and standards are compared by an example,and it is recommended to use the range of one-dimensional compression zone to judge the type of wide and narrow embankment of soft soil foundation.（3）This paper expounds the technical challenge for the soft soil embankment settlement calculation,the PLAXIS,BCF two models based on Biot consolidation theory and finite element software development,including pretreatment,including material model,element subdivision,initial conditions,boundary conditions,construction simulation,etc.),calculation process and post-processing application level,discusses their features,recommended priority choose PLAXIS subsequent numerical simulation software.（4）Based on the PLAXIS finite element software,a nonlinear numerical model for calculating the settlement of wide and narrow embankment in soft soil was built.The stability,settlement of foundation surface,settlement of subgrade surface,lateral displacement of foundation section at the foot of embankment slope,and overpore water pressure in soft soil foundation were analyzed under the action of load of wide and narrow embankment.（5）Using the finite element software PLAXIS,on the basis of the numerical model of wide and narrow embankment established above,the parameter sensitivity analysis was carried out,and the influence law of cross section geometric parameters,soft soil material parameters and embankment construction parameters on the settlement of soft land foundation of wide embankment was discussed.（6）Organizing the domestic highway industry technical specification on embankment settlement calculation of soft soil foundation,combined with a specific example,demonstrated the standard analytical method,the general principle is geotechnical software and Settle^3D software,the feasibility of the application in the wide embankment settlement,discussed the Tang Zhicheng,Zhang Limin proposed the characteristics of the wide embankment settlement analytic formula.Although the two software can calculate the consolidation settlement of soft soil embankment,it cannot describe the typical characteristics of the settlement law of soft soil foundation wide embankment.The analytical formula of wide embankment settlement put forward by Tang Zhicheng and Zhang Limin still needs to be improved.