The Fluid Solid Coupling Analysis Of Vacuum Preloading

The paper is based on the field engineering of the Xingheng expressway and the centrifuge test to study the vacuum-surcharge preloading,which is aimed to reinforce the soft soil subgrade.It shows that, by the results of settlement,the settlement curve of the centrifuge drops very quickly firstly,but it reduces also very fast.The settlement curve of the field engineering also drops fast firstly,but the velocity of reduction is slower than the centrifuge.In the angle of water pore press and the effective stress of soil, with the increasing of depth,the water pore press gets bigger and the effective strss is smaller.The dissipation of water pore press of the filed engineering is more than the centrifuge test,and the increasing of the effective strss is also more than the centrifuge.Above all,the reinforcement effect is better than the centrifuge.The uses the Discrete element software to make the fluid solid coupling analysis for the centrifuge test.In both of the two situation of distance 2.6m and 1.3m,the water in the of seepage field is downward and the particles velocity of the in the displacement is downward too.It shows by the comparsion of two kinds of the results,the reinforcement effect of the distance 1.3m is better than the distance of 2.6m.By studying the results of the distance 2.6m,the paper derives the scene model.It shows that, the water in the of seepage field is horizontal and the particles velocity of the in the displacement field is also downward,but they also have the weak horizontal velocity because of fluid solid interaction.The settlement of the subgrade surface is close to the measured value of the field engineering and the the change of porosity is more clear. Above all,it shows that,both of the measured value and analog value,the reinforcement effect of the silty clay layer is the best,and the aim of focusing on the soft soli is reached.