STUDY ON STRENGTH PARAMETERS OF SOFT INTERLAYER FOR LARGE AND SMALL DIRECT SHEARS

Soft interlayer in rock mass is the most important boundary condition to stability of rock mass. So it is instructive to obtain an accurate and reasonable mechanical parameter of these layers, especially in selecting a good dam base and evaluating the stability of the dam base. For some deep-seated soft interlayer, it is difficult to obtain its mechanical parameter by testing of large-size samples, whereas the shear strength of this layer can be obtained by small-size direct shear of small samples. Therefore, we can calculate the parameters for soft interlayer according to the relationship of experimental value between large and small direct shears.