Study on the Strength Characteristics of Polypropylene Fiber Modified Smuck

With the construction of more and more tunnels, the amount of shield muck will continue to rise, and the shield muck gradually becomes the main source of solid waste in developed cities. The fiber can effectively improve the strength of soil, so the shield muck can be utilized by the fiber to improve the shield muck. This paper takes the shield muck of a large diameter shield tunnel project in Beijing was taken as the research object, the independent development of curing agent and polypropylene fiber improvement were used for soil improvement. The strength characteristics of polypropylene fiber modified soil blocks and pure curing agent modified soil blocks were compared and analyzed indoors, and the microstructure of the samples was studied by SEM. The results show that: When the polypropylene fiber content of the modified shield muck fiber is 0.5%, the maximum lateral confined compressive strength value is 1026 kPa, which is 77.5% higher than the lateral unrestricted compressive strength of the soil modified with pure curing agent. The cohesive force of fiber modified soil is 304 kPa, which is 36.9% higher than that of pure curing agent. The friction angle in the fiber modified soil is less affected by the fiber content. And the polypropylene fiber forms a very strong physical connection with the modified soil, which improves the integrity, strength and stability of the soil.