Analysis Of Bearing Capacity Of Cement Deep Mixing Column In Soil Improvement

With the rapid growth of foreign trade, in order to satisfy the maritime freight transport demand, Vietnam in recent years has invested large amounts on deep water port construction. As the coastal geological weakness, it is necessary to adopt the appropriate method to improve the bearing capacity of foundations. Cement deep mixing method (DMM) has proved its applicability of the soft soil, construction speed, and economical advantages; therefore the application of DMM in soft soil improvement is more and more widely.The strengthening mechanism of Cement deep mixing method is the use of deep mixing machine to curing cement transported to the soft soil layer, while mechanical stirring, to form a composite foundation, significantly increase the strength of natural soil. Top load applied on composite foundation is supported by cement treated soil column and the soil between columns. The stress state of piles and soil decides the bearing capacity of foundation.Pile-soil stress ratio of composite foundation is the characteristic parameters of the stress state. Reasonable control of pile-soil stress ratio of composite foundation can increase soil improvement effect. In order to optimize design and improve the computation theory, this paper uses finite element method to make model of composite foundation for the analysis. The analysis is processed to specify two major effects of pile-soil stress ratio: cement ratio of composite foundation and pile spacing.The analysis processed with ABAQUS, powerful finite element software, which is applicable to solve both simple problems, e.g. linear analysis, neither complicated nonlinear problem. ABAQUS has powerful element libraries, able to simulate arbitrary geometry, and many types of material models that can simulate the performance of typical engineering materials, including rock and soil materials. ABAQUS has proved its calculation capacity and reliability in soil engineering researches and practices.