Study On Friction And Anchorage Characteristics Between Root System And Soil

The key of retaining soil of roots is the friction and anchorage between root system and soil. In order to explore the friction characteristics between root and soil, the influence of different conditions such as spices, root burial depth, soil moisture content, dry density of soil, loading rate and root diameter were examined by using direct pulling out tests with the self-developed roots pulling test machine. Based on this and the formula:F=1/2μπDρd(1+ω)gL2, the influence of friction coefficient between root and soil by the conditions mentioned above were studied. And the results show that:The single root tests have two main failure modes:pulled out and broken, the group root system tests have three main failure modes:pull out, broken and split. The L-S curves of broken single roots have two steps:steep rose and steep declined, the L-S curves of pulled out single roots have three steps:steep rose, steep declined and gentle declined, the L-S curves of group root system are similar to the curves of pulled out single roots.The friction of single root-soil increased with the increase of root diameter, root burial depth, loading rate and dry density of soil. The friction of single root-soil increased and then declined with the increase of moisture content of soil. The smallest friction belongs loPinus tabulaeformis root-soil, and the largest friction belongs to Larix gmelini root-soil.The peak slippage increased with the increase of root burial depth and loading rate, the other conditions have no remarkable effection to peak slippage.The friction coefficient of root-soil increased with the increase of loading rate and dry density of soil, increased and then declined with the increase of moisture content of soil. Root diameter and burial depth have no remarkable effection to friction coefficient.The friction between group root system and soil increased with the increase of included angle, the sum of the roots diameter and the decrease of the deviation of the roots diameter.