Abstract:Shixia Basin is located at north of Miyun Reservoir, it is the first level nature reserve as well as an important water source of Beijing area, but suffering from serious soil erosion and debris flow. Slope engineering measures may decrease soil loss of the slope, accumulate aggregates, and increase slope stability. Terrace and horizontal bar are two kinds of engineering measures well adopted in Beijing area. To investigate the effects of engineering measures on slop stability, and understand the effects of soil physical properties (soil bulk density, soil moisture, total porosity, capillary porosity, non-capillary porosity, firmness and liquid limit) on soil shear strength, the changes of soil shear force with depth under different engineering measures, soil shear characteristics and the affecting factors were studied. The results showed that soil critical shear force increased with soil depth. The relationship between soil shear strength calculated by Coulomb formula and soil critical shear force measured in situ fitted with the equation: σ=0.0123τf+0.6308. Cohesion and angle of internal friction on and down the channel of irrigation differed slightly, but shear strength differed significantly. The effects of soil physical characteristics varied, among which soil compaction, volume-weight and moisture content had the most significant effects. The anti-shear ability ranked as follows: terrace>horizontal bars>bare land, and the anti-shear ability of the horizontal bars with conifer was better than the one with deciduous trees. In the area of Miyun, Beijing, when carrying out engineering measures, it is important to increase the width of terrace, and establish mingled forest of conifers and deciduous trees.