برآورد ميزان افزايش مقاومت برشي ساحلي كارون با استفاده از ژيومتري ريشه هاي درختان گز و پده

Investigation of the effects of tamaricaceae and popoluse roots on the stability of Karoon banks by root geometry

Bio-technique methods, use of vegetation especially tree for stability of river banks or natural slopes, have been received more attention by many river engineers nowadays. The most notable effects of tree roots are: increase of soil strength through reinforcing the soil. Roots of tree and other vegetation provide a reinforcing effect to soil through tensile resistance and frictional or adhesion properties. The reinforcing effect or increase of shear strength in soil due to presence of root can be quantified by Barkerʹs type equation. In this study attempt have been made to investigate the effects of two common tree species in the stability of Karoon riverbanks. For the purpose of this study, the geometry, and the characteristics of these tree roots were collected. Applying these data and a computer model, which developed for this study, the distribution of roots and the ratio of root cross-section relative to the total shear cross section were computed for any depth and distance. The maximum root tensile force measured for 59 root samples was correlated to the root diameter. Using Barkerʹs type equation, the amount of soil shears strength for these trees were computed in different depth. The results show that the roots of tamaricaceae has increased the soil shear strength more than the popoluse roots especially for depth up to 40 cm. The amount of soil shear strength increased is higher for the popoluse at deeper depth and reaches to a maximum of 21.6 Kpa at depth of 150cm.