Characteristics and mesoscopic mechanics of vegetation roots damage induced by mining in western mining area

Roots damage is an important inducement of vegetation degradation in western arid and semi-arid mining ar- ea when mining. Based on field investigation and related literatures on the background of Shendong mining area,this paper proposes two phenomena of roots damage induced by mining,strain controlling and stress controlling. Through building the interfacial shear debonding model of single equal-diameter root,the “ elastic-slipping-debonding” three stages of root-soil interface stress deformation process induced by mining are studied. The shear stress-strain curve of root-soil interface is deduced,and then the mesoscopic mechanics of three typical roots damage are revealed. Further- more,by simplifying the dominant plants salix psammophila and artemisia desertorum into full length anchorage unit and root-soil composite layer,the force-deformation zoning characteristics of macroscopic response to mining is modeled with FLAC3D . The results show that high tensile stress is the control factor for full length anchorage unit above the gob span and that non-consistency and non-integral of force is the control factor for full length anchorage unit near the boundary of gob. The shear stress level on the bottom of root-soil composite layer above the gob is higher than that on the top,hence,it is easier to form a large area of shear damage area on the bottom of root-soil composite layer above the gob. The tensile stress level on the bottom of root-soil composite layer along and outside the boundary of gob is low- er than that on the top,hence,it is easier to form a large area of tensile damage area on the top of root-soil composite layer along and outside the boundary of gob.