Analysis On Air Pressing Consolidated Drained Method

Air Pressing Consolidated Drained Method is a new method of soft foundation consolidation, which obviously has more advantage than traditional ones. The air cells could be recycled. The method is low in energy consumption, sand-rock dosage and total cost. And the method is also good at giving more pressure on solid, shortening the time of consolidation, resulting in better effect and especially suiting consolidation of deep soft foundation. Therefore, it's necessary to analysis the feasibility of Air Pressing Consolidated Drained Method (short for Air Pressing Method: APM), to carry forward application of it.The paper firstly introduces the device and operation flow of APM and analyses the mechanism of APM and the time interval of air refilling to air cell. Then based on finite element theory of software PLAXIS, the finite element model of AMP is founded, combination of loading and interval of air cell is optimized, and the consolidation effect of optimized model is analysed. Several methods to enhance the effect of AMP are proposed. At last, combining with engineering project, through finite element calculation, the consolidation effects of AMP and vacuum preloading are compared with each other, which demonstrate the feasibility and advantage of AMP.The analysis result shows, the more the longitudinal sections of air cells are, the more equal the compression of solid will be and the higher the consolidation rate of disposed solid will be. As the air cell spacing decreases, the consolidation rate of disposed solid increases first and then decreases. The more the vertical drainage pipes are, the higher dissipating speed the excess pore pressure will have and the shorter consolidation time. Multistage loading, adding vertical drainage pipes and adding load will do good to AMP effect in varying degrees. AMP is better in deeper solid layer and suitable for deep solid consolidation; meanwhile the vacuum preloading is better in superficial solid layer. Therefore, these two can be combined together.In conclusion, AMP is a feasible way to consolidate soft foundation. The paper gives a certain consult for further study and application of AMP.