The Performance Of Soft Clay Based On Composite Reinforcedimproved Method

With the development of geosynthetics, reinforced soil has been used in retainingwalls, dams, revetments and other hydraulic and environmental engineering. Thecurrent research on reinforced soil suggests that only sandy soil can play a role of thefrictional resistance of interfaces between reinforcement and soil, which can enhancethe strength and stability of soil mass. Therefore, sandy soil is required in design, usedas filling in reinforced soil engineering. However, as is known to us all, it is difficult toget the soil conforms specification and plays the completely reinforcing role in manyareas of our country due to the scarcity of sandy soil. In the principle of protection ofenvironment and land resources, lots of susceptible soil, like the cohesive soil or softplastic clay, must be available for practical engineering. However, experience over thepast few years has proved that the reinforcing effect of reinforced clay soil is notobvious. This is because the reinforced cohesive soil or soft clay have received littleresearch attention, and the reinforcing mechanisms remain unknown, so directutilization of them into engineering may bring potential dangers. The treatment andmechanism of reinforced soil for viscous clay should be further researched.Based on plastic cohesive soil, improvement on soft plastic cohesive soil andreinforcement methods was studied in this paper. Then, a compound improvementwhich combined the methods of reinforcement and solidification was proposed, ease touse local materials, safety, security. In the research, first the experiments for researchingthe improvement mechanism of soft plastic clay by lime and polypropylene fiber werecarried out. A compound improvement was presented by comparing the experimentalresults under various conditions. Then, the reinforced mechanism of improved softplastic clay was researched by the mechanical properties and collapse mechanicsobtained from triaxial tests. Finally, by a numerical simulation on account of FLAC on ahypothetical example, feasibility of the improvement method mentioned above wasanalyzed and assessed. The main works of this paper are as follows:①Determine improvement programs on compound reinforcement. Lime andpolypropylene fibers in different proportions was added to improve soft plastic cohesivesoil. Experiments showed that: lime can raise the strength of the soil mass, as well as itsbrittleness; polypropylene has a light influence on enhancing soil’s strength, but a heavyinfluence on improving soil’s ductility. Thus, combining them provided a compound improvement method, which is adding lime and polypropylene fibers in differentproportions into soft clay. Polypropylene fibers with different mass ratio of0%,0.05%,0.15%,0.25%was mixed into37lime soil and triaxial experiments wereconducted to test shear strength and deformation failures. Results in those experimentsshowed that a polypropylene fiber with a mass ratio of0.25%was the best program.②Analysis on the performance of reinforcement of soil mass after improved.Selected aluminum foil as a reinforcement according to the tensile properties byanalyzing the problems existing in the triaxial test of reinforced soil, a series of triaxialtest had been carried out on studying the reinforced performance. From the results oftests, it is shown that the shear strength of the improved soils have been increased afterreinforced.③Numerical Simulation. Simulated in FLAC3D,it was shown that theimprovement of soil used for ground treatment is greatly increased on the foundationbearing capacity compared with soft clay, meanwhile, the settlement of foundation isgreatly reduced. Therefore, the reinforcement has remarkably reinforcing effect on theimproved soft plastic clay, it is applicable to reinforced soil engineering.