Numerical Investigation On Application Of Stone Column To Improving Soft Ground In The Mekong Delta

In the Mekong Delta,construction troubles may be encountered due to the soft ground with very low bearing capacity,and high compressibility.As a result,the soft ground shall be treated to improve its engineering properties as per design requirements for the bearing capacity and the settlement.In this work,stone columns are utilized to reinforce the soft ground and improve its engineering properties.Firstly,theoretical aspects on the stone column-reinforced soft ground are introduced,and then numerical simulations are performed using the commercial finite element software PLAXIS to study the characteristics of stone column-reinforced soft ground.Based on the numerical results,the following conclusions or observations can be achieved:(1)With the stone columns,the bearing capacity of soft ground can be improved by 30%?150%,and the settlement decreased by 2?3 time,however,the improvement extent shall depend on those parameters,including the area replacement ratio,the length,diameter,and spacing of stone columns.(2)The material properties of stone columns may significantly affect the overall bearing capacity and the settlement of soft ground,since it can be observed that by increasing the stiffness and strength of column,the bearing capacity of the composite ground increases and the settlement decrease significantly.(3)The analytical results for the engineering properties of the composite ground were compared to those attained from 3D and 2D finite element simulations and it was found that the 3D numerical model is general superior to the 2D model for predicting the work performance of the composite ground.(4)The ground improvement method with stone column was successfully applied to an actual project in Mekong Delta,Vietnam.Both the analytical results and finite element analysis results indicate that stone columns not only can reduce the total settlement,but also can accelerate the ground settlement rate under the applied load.The treated ground can reach 53%?93%of the degree of consolidation just after construction stage.(5)Finally,compared to other ground treatment methods such as method of soil-cement columns and deep foundations,the stone column-reinforced soft ground improvement method are lower in construction cost and flexible in technical treatment.