Abstract: According to geological situation of the Manjiazhai open-pit project, more representative rock-soil layer at west slope confirmed through field investigation, in-situ direct shear test was done by using artificial digging and soil-stone bags load method. Through analysis of experimental data, τ~ε curve obtained, shear strength σ~τ relationship curve and corresponding shear strength parameters c, Φ value and correlation coefficient r were obtained by using least squares regression. The test indicates that in-situ direct shear test of west slope has the important value to slope stability evaluation of open pit and engineering optimization.

Key words: Slope, In-situ direct shear test, Shear strength, Deformation