Study On The Influence Of Herbs In Different Growth Periods On The Stability Of Shallow Slopes

In order to study the influence of herb roots in different growth periods on the stability of the shallow slope,the Haizhou Mine was taken as the research site to conduct on-site investigations.The research objects were determined to be Viola philippica,Chenopodium album,and Setaria viridis.Three kinds of herbaceous plants were cultivated,and the tensile force of roots at different growth stages was measured by tensiometer.At the same time,the vernier caliper and the image pixel conversion method were used to determine the root area ratio of the three herbs in different growth stages.The root reinforcement effect of herbs at different growth stages was quantified by the revised WWM model.A slope model was built,and the reinforcement effects of herbs in different growth periods was added to the surface of the slope model.The limit equilibrium method was used to calculate the safety factor of the slope under different slope lengths and angles under different growth periods with herbaceous plants,and analyze the variation law of the safety factor.Further combined with the actual engineering and the growth distribution characteristics of plants,species weights are introduced,and the calculation scheme of root additional cohesion during planting of various herbs in different growth periods is given.The research results show that:(1)The tensile force of plant roots has a positive correlation with the growth period,and the tensile force and diameter of plant roots in any growth period have a power-law function relationship;(2)With the increase of the growth period,the root area ratio of the three herbs gradually increased,and at any growth period,the root area ratio decreased with the increase of the soil profile depth;(3)With the increase of the growth period,the reinforcement effect of the three herbs gradually increased.(4)With the increase of the growth period of the herbs,the safety factor of the slope in any working condition increases gradually,and the reinforcement effect of Viola philippica of the three herbs is better.(5)In any growth period,herbs can improve slope stability.In order to calculate the root additional cohesion under the planting of multiple herbs at different growth stages,a scheme to quantify the root additional cohesion of multiple herbs was proposed using the weighted Topsis method combined with the revised WWM model.The herb growth characteristics at one-time point in the mine herb growth area verified the feasibility of the scheme.This study can provide a reference for ecological slope fixing engineering.