The Research On Soil Anti-shear Strength Of Different Forest Plant Communities In The Simian Mountain, Chongqing

Soil anti-shear strength is the research on soil erosion from the point of mechanical properties of the soil, which is one of the quantitative indicators and measure the anti-erosion ability of forest plant communities.Performance is mainly determined by the soil physical properties,soil density, moisture, porosity, clay content and the forest root such as other factor.Soil resistance and pastes cohesion and internal friction angle, is the two indicators which evaluate the performance of soil shear.Through undisturbed soil direct shear tests and triaxial tests of remolded quantitative analysis on soil anti-shear strength of six forest plant communities in the simian mountain and through principal component analysis and multiple regression analysis on the relationship between soil shear strength and soil physical properties, root density.The results showed that:the direct shear tests, the largest of soil cohesion and pastes the value of resistance is evergreen and deciduous broad-leaved mixed forest, warm bamboo forest is minimum; Internal friction angle of warm needle-leaved forest showed the largest, followed by warm bamboo forest, temperate needle-leaved forest showed the smallest.reconstruction of soil using triaxial test, soil cohesion and pastes the value of resistance showed the largest mixed evergreen and deciduous forest, warm bamboo forest minimum; internal friction angle showed the largest evergreen broad-leaved forest, temperate coniferous forest minimal.A certain pressure range, the performance of forest plant communities and vertical shear stress is linear.Anti-forest plant communities and pastes cohesion value of the friction angle increased with soil depth, the change is different.The main effect of soil shear Factors:natural water content, soil density, porosity, non-capillary porosity and clay/silt, the main factor on forest plant communities in different shear effects.Root density and soil shear strength of a linear relationship, particularly as the root diameter≤1mm of the increase in density of fine roots, soil shear performance was enhanced.