Use two special soil of southwest mountainous areas of red clay soil and powdered coal as research object

by conventional direct shear test

to study the influence of moisture content on these two soil of cohesion and internal friction angle

shear strength and other characteristics parameters. The results indicate that the red clay and powered soil of coal measure strata have water sensitivity

and the red clay water have larger sensitivity. With increase of water content

the cohesion of red clay decreases in segments. When water content approaches saturation moisture content

the cohesion of red clay is stable. The internal friction angle of red clay keeps stable at the beginning and then sharply declines with water content increasing. With increase of water content

the cohesion of powered soil of coal measure strata and its water content decreases in the form of exponential function

while its internal friction angle decreases in the form of linear function. The research results provide a reference for the region of soil mechanics calculation parameter selection.