Analysis On Mechanism Of Reinforcement Of Soft Soil Foundation By Air Injecting Drainage Method

With the large-scale development of coastal land reclamation projects in China’s coastal areas,the high bearing capacity of low-water-filled soils has a low bearing capacity and high compressibility characteristics,which has become the key problem affecting the construction of the project.Gas injection disturbance drainage method is a kind of new soft soil foundation treatment method which takes into account the technical characteristics of surcharge preloading and gas injection disturbance.In this paper,the aerodynamic cleavage mechanism of gas injection disturbance method is analyzed by using indoor simulation test,theoretical analysis,field test and numerical simulation.Mathematical model and 3D finite element model are established based on pneumatic splitting mechanism.The main contents and conclusions are as follows:(1)The feasibility and effectiveness of the gas injection disturbance method are verified by the indoor model test.The influence of the gas injection parameters on the reinforcement effect is studied.The gas injection disturbance method can significantly accelerate the consolidation of the foundation and improve the soil strength.In addition,increasing the gas injection cutting surface and gas injection pressure,can improve the reinforcement effect of the soil.(2)The mathematic model of aerodynamic fracture diffusion was established by using MATLAB.The influence of gas injection parameters on the characteristics of aerodynamic fracture was studied.The fracture radius was positively correlated with gas injection and gas injection depth,but negatively correlated with gas injection pressure.Gas pressure and gas pressure are positively correlated,but negatively correlated with gas injection depth.(3)The numerical model of soft soil treated by gas injection disturbance was established by PL AXIS.By analyzing the changes of super-static pore pressure,stress-strain and settlement of soft soil during consolidation,the gas-Soil micro-mechanism:plastic drainage board and the formation of high pressure gas permeability of the disturbance surface of the common role,increase the super-static pore pressure dissipation channel to speed up the soft soil drainage consolidation,improve soil strength.