Studies On Interface Properties Of Geosynthetics And Construction And Demolition Waste

The use of construction and demolition waste(C&DW)as filler for reinforced earth structures can not only effectively utilize the resource of C&DW,but also reduce the environmental pollution caused by C&DW.The interface properties of C&DW and geosynthetics can directly affect the application of C&DW in reinforced earth structures.In this paper,the influence of physical parameters and moisture content of C&DW on the mechanical index of C&DW and the interface properties of C&DW and geosynthetics are studied through laboratory experiments,and the numerical simulation analysis of large-scale direct shear tests is carried out by using ABAQUS software.The following research results were obtained:(1)The effects of moisture content and particle gradation on the shear propreties of C&DW were studied by 6 groups large-scale direct shear tests.The results show that with the increase of moisture content,the peak shear stress,cohesion and internal friction angle of C&DW decrease gradually,the vertical compression value increases gradually;and three types of particle gradation C&DW used in this study have similar peak shear stress.(2)The effects of the C&DW moisture content,the particle gradation of C&DW and the types of geosynthetics on the interface shear properties of C&DW and geosynthetics were studied by 16 groups large-scale direct shear tests.The results show that with the increase of moisture content,the interface peak shear stress and friction angle between C&DW and geosynthetics gradually decrease,and the vertical compression value increases gradually;for woven geogrid and non-woven geotextile,the interface cohesion increase with the increase of moisture content;for extruded geogrid,the interface cohesion decrease with the increase of moisture content;for the three types of particle gradation C&DW used in this study,with the decrease of uniformity coefficient,the interface peak shear stress and interface cohesion between C&DW and geosynthetics gradually decrease;the interface peak shear stress of C&DW and extruded geogrid is the largest;the range of interaction coefficient between C&DW and geosynthetics is 0.86-1.46.(3)Numerical simulation of large-scale direct shear test was carried out by ABAQUS software,the distribution of the interface shear stress in the process of test and the influence of ratio of the transverse rib area to the area of shear interface and moisture content on the interface properties of C&DW and geogrid are studied.The results show that in large-scale direct shear tests,the interface shear stress and the tensile stress of geogrids decrease gradually along the shear direction;when the ratio of transverse rib area to the area of shear interface increases from 0% to 18%,the interface peak shear stress between geogrids and C&DW increases by 26.4%,while when the ratio increases from 18% to 36%,the interface peak shear stress between geogrids and C&DW increases by only 9%;for the geogrids with the ratio of transverse rib area to shear interface area of 36%,18% and 0%,when the moisture content of C&DW increases from 18% to 30%,the interfaces peak shear stress decreases by 17%,20.1% and 26.7% respectively.