Effect Of Bison Grass Root System On Shear Strength Of Slope Soil

In recent years,the number of slope treatment using vegetation slope protection technology has increased significantly.Bison grass has strong adaptability and can be considered for vegetation slope protection.Therefore,this paper studies the influence of bison grass root system on soil.The pull-out strength of root system and tensile strength of bison grass root system of rooted soil,and the influence of bison grass root system on shear strength of rooted soil and slope stability are analyzed.The main aspects and results of this paper are as follows:Through the pull-out test of bison grass root system,when the moisture content of the soil containing roots is 9%-12%,most of the roots are pulled off because of the large friction between the roots and the soil;When the water content is 15%-21%,the vertical load and the diameter are different,which shows the pull-out and tensile failure;When the water content is24%-27%,the friction between roots and soil is small,and most of them are pulled out.In the root tensile test,the root tensile strength of bison grass increased with the increase of root diameter,and the trend increased exponentially.The root tensile strength decreased with the increase of root diameter,and the relationship was negative.Through the direct shear test of undisturbed soil,the growth time is 90d and 180d,and the direct shear test of undisturbed soil of bison grass under different precipitation conditions,it is found that the root content reaches 12-14.5g×10^-3/cm³,the shear strength and cohesion of soil mass reach the maximum;The shear strength index of undisturbed soil of bison grass roots grown under normal conditions was higher than that of the other two groups.Through the direct shear test of remolded soil,the shear strength is the largest when the root system is mixed（vertical and inclined 40°-45°）.Root content:11.67-15g×10^-3/cm³,There is an optimal value in the range of 10-3/cm3,which makes the soil shear strength reach the maximum.The water content is in the range of 16%-19%.The shear strength reaches the maximum value,and the root content is 13.33-16.67g×10^-3/cm³,and the cohesion reaches the maximum;The internal friction angle is less affected by the root content.Using ABAQUS finite element software,the slope stability is analyzed by strength reduction method.The 0.5m long root system can only reinforce the slope within the range of about 2.1m from the slope toe.In other locations,the safety factor of the slope with root system is not different from that without root system.With the increase of root length（root penetration depth）,the slope safety factor is improved.The slope stability with root system is generally higher than that without root system.Through the research on the soil containing bison grass root system,it is found that bison grass root system can effectively increase the shear strength and other indicators of soil.Bison grass can be used for vegetation slope protection.