The effects of dry density and moisture content on the shear characteristics of clay-type muddy interlayer

Clay-type muddy interlayer is a key control factor leading to the instability of layered slopes, and it is of great significance to carry out the research on the shear characteristics of clay-type muddy interlayer for the safety and stability of layered slope projects. In this paper, the shear characteristics of clay-type muddy interlayer under different conditions of dry density and water moisture content are investigated by improving the test apparatus and data processing method. The results show that: the internal friction angle of clay-type muddy interlayer decreases with the increase of dry density under the condition of low moisture content, while the cohesion increases with the increase of dry density; at medium moisture content, both of them fluctuate with the dry density, but the amplitude is not large; at high moisture content, the response effect with dry density is not obvious. Therefore, higher dry density improves the shear properties of the soil by strengthening the friction and occlusion between particles, while increasing moisture content tends to weaken the shear properties, mainly due to the reduction of the lubrication effect of water, which gradually reduces the cementation between soil particles and the force of water film connection. On the one hand, the research results can enrich the complex mechanical response mechanism of clay-type muddy interlayer in different conditions, and on the other hand, it also provides a certain theoretical basis for the disaster prevention and early warning assessment of this kind of slope engineering.