Experimental Study On Preloading Of Dewatering And Loading Combined With Dynamic Consolidation Method In Reinforcing Soft Foundation Of Shantou

Based on a Highway foundation treatment project of Large-scale reclamation site inShantou coastal economic zone, the reinforcement mechanism of typical sections’ SoftFoundation is studied by using Preloading of dewatering and loading combined with dynamicconsolidation Method. The changes of foundation deformation and excess pore water pressurewith time, the dynamic characteristics of dynamic consolidation, the role dynamicconsolidation plays in, and the reinforcement effect after-treatment are analyzed. The finiteelement analysis model of soft soil consolidation is built. Through the comparison betweencalculation results and measured data, conclusions are obtained as follows:(1) Using step loading, Preloading of dewatering and dynamic consolidation to reinforcethe soft soil ground are used. After reinforcement, the cohesion values of②1silt stratificationincrease from8.7kPa to18.6kPa, the cohesion values of④1silt increase from17.2kPa to29.85kPa, the bearing capacity characteristic value is greater than120kPa.(2) The experiment lasts for210days, total consolidation settlement is527mm, where inthe first stage preloading filling is1.3m, lasts for95days, consolidation settlement is279mm.After compaction, consolidation settlement is428mm. The second stage preloading filling is2m, lasts for110days, consolidation settlement is62mm. After compaction, consolidationsettlement is99mm; After the end of the first compaction, maximum settlement is149mmwhich is28%of total settlement values. After the end of the first compaction, maximumsettlement is82mm which is15.7%of total settlement values. The effect of dynamiccompaction is obvious.(3) During the soft ground foundation treatment process, excess pore water pressureincrease up to a maximum value of about10kPa, then dissipate quickly fell back to normal in2day. The best interval time between twice point ram is greater than2d.(4) Under the action of dynamic compaction, the acceleration peak is continuousattenuation with the increasing distance between tamping points and measuring point. Verticalacceleration value is2.4times the horizontal direction the same measuring point. Levels rangeof compaction was about15~20m. From the same point repeatedly rammed tamping of view, the acceleration values of the third tamping is the largest. The first two tamping energy isconsumed in most on the surface soil compaction process.（5）The numerical results shows, the numerical simulation results is consistent with theon-site monitoring settlement curve in the filling stage. During the course of the twopreloading, Sedimentation value of the numerical simulation is2.8%larger than on-sitemonitoring data in the first filling, however when the second filling the sedimentation valueof the numerical simulation is13%smaller than on-site monitoring data.