Abstract: The clay content in red clay is very high. In order to explore the influence of clay content on the physical and mechanical properties of the red clay, the Guilin Red Clay samples are used as the research object. The tested clay content in the soil samples is 42.3%. The clay sample is prepared by using the principle of clean water sedimentation. Different clay contents are added to different Guiling Red Clay samples, and the specific gravity test, water content test and triaxial shear test are performed on these samples. The results show that, the specific gravity of soil particles first decreases and then increases with the increase of clay contents. The water content ratio gradually increases with the increase of clay contents and the cohesion increases step by step with the increase of clay contents. The internal friction angle decreases step by step with the increase of clay contents. The specific gravity curve and water content ratio curve are fitted, and the results are close to the form of power function.

Key words: Geotechnical Engineering, Red Clay, Clay Content, Specific Gravity of Soil Particles, Water Content