Experimental research on the influence of mica on strength of cement-reinforced soft clay

Soft clay is of the characteristics of strong compressibility and low bearing capacity. Cement is used as curing agent to strengthen soft clay in engineering. Mica is a kind of mineral widely distributed in soft clay, and its content and particle size will affect the strength of the cement-reinforced soft clay. The influence law among the mica content and mica mesh number on strength of the cement-reinforced soft clay is studied based on direct shear tests and unconfined compressive strength tests. Based on the experimental data, the mathematical relationship between the content and mesh number of mica and soil-cement strength is established. The number of mica meshes in the experiment is 10, 20, 40 and 80 mesh, and the mica content is set as 0%, 8%, 16% and 32%. The results show that as the content of mica increases or the number of mica meshes decreases, the unconfined compressive strength and shear strength of the cement-reinforced soft clay show a decreasing trend, and the effect of mica on the unconfined compressive strength is more significant. When the number of mica mesh in the cement soft clay is 10 mesh and the content is 32%, the strength of the cement soft clay decreases the most. In this case, the unconfined compressive strength of 0.33 MPa is 25.5% of that of the cement soft clay without mica, the cohesion is 76.5 kPa, which is 12.24 kPa less than that of the cement soft clay without mica, and the internal friction angle decreases from 23.71° to 21.77°. It is speculated that the lamellar morphology of mica and adverse effect on cement hydration are the main reasons for the decrease of the cement soil strength.