Influence of water contents on shear strength of coal-bearing soil

Coal-bearing soil is weakened when encountering water and its strength is sharply dropped down with increasing water content.Taking coal-bearing soil which ranges along with Guang-Wu Expressway for example,and based on analyzing the physical properties of coal-bearing soil,its shear strength is measured through direct shear test;influence of water contents on shear strength of coal-bearing soil is analyzed;and some suggestions are put forward to treat coil-bearing soil.The results indicate that the shear strength and initial water content of coal-bearing soil have marked correlationship;and the bigger initial water content of coal-bearing soil is,the smaller its shear strength is.With water content increasing,cohesion of coal-bearing soil decreases overall;but its changing trend is of marked characteristic of stage.When water content of coal-bearing soil is under some value,its cohesion changes in small ranges;after water content of coal-bearing soil is over the value,its cohesion decreases with water content increasing;and the interrelationship between the logarithm of its cohesion and water content is linear.Water content of coal-bearing soil has no marked effect on its internal friction angle;but its internal friction angle firstly increases and then decreases,so it has marked peak value.