Field Test Study On Strengthening Soft Soil Foundation By Gas Injection Improved Drainage Method

With the rapid development of the economy,the coastal land reclamation project has been carried out on a large scale in the coastal areas,conventional foundation treatment methods are difficult to meet the requirements of short construction period,highly settlement control requirements,etc..The gas injection improved drainage method is a new method formed by the improvement of the conventional surcharge preloading method in combination with the gas pressure splitting technology.In this paper,the field test of the soft soil foundation reinforced by the gas injection improved drainage method was carried out,and the three-dimensional model was established by numerical analysis software ABAQUS for numerical simulation analysis.The main contents are as follows:(1)Field trials were conducted on the improved gas drainage method and the conventional surcharge preloading method to reinforce the soft soil foundation.The consolidation effects of the two foundation treatment methods were compared and analyzed.The results show that the gas injection improved drainage method can effectively accelerate the soil consolidation rate without destroying the structural properties of the soil,and can reinforce the deep soil more effectively.(2)The conventional surcharge preloading method was studied by numerical simulation.Selecting the Mohr-Coulomb model as the soil constitutive model and combining with Biot consolidation theory,a three-dimensional numerical model was established using ABAQUS numerical analysis software to simulate the conventional surcharge preloading test section.The numerical simulation results and field test data were compared to study the variation of settlement and excess static pore water pressure in various construction stages.(3)The gas injection improved drainage method was studied by numerical simulation.Combining the theoretical analysis of the pressure splitting process and the actual conditions of the field test,a simplified simulation method for the gas injection process was proposed.A three-dimensional numerical model was established to simulate the gas injection improved drainage test section.The numerical simulation results and field test data were compared to study the variation of settlement and excess static pore water pressure in various construction stages.