| The denti-geogrid is a new type of three-dimensional reinforced structure.It absorbs the advantages of the friction characteristics of the traditional horizontal geogrid,and its vertical denti-reinforcement can play a good role in lateral resistance.Compared with the traditional geogrid,the denti-geogrid can greatly improve the bearing capacity of soil and improve the overall stability of the project.At present,the research on the working mechanism and calculation method of three-dimensional reinforcement is still imperfect,which needs further exploration.Based on the indoor pull-out test and the upper bound theory of limit analysis,this paper systematically studies the pull-out characteristics and working mechanism of geogrid reinforced structures with teeth.The main research contents and achievements include the following three aspects:(1)Through 100 groups of indoor drawing tests,the characteristics and working mechanism of the reinforcement-soil interface of the reinforced structure with denti-geogrid are analyzed,and the working performance of the reinforced structure is compared with that of the traditional horizontal geogrid,which verifies the feasibility and effectiveness of the reinforced structure with denti-geogrid.The test results show that due to the lateral resistance of the denti-reinforcement,the interface strength between the denti-geogrid and sand is significantly improved.Under the same test conditions,the reinforcement effect of denti-geogrid is better than that of traditional horizontal geogrid.(2)The influence of upper coating load,denti-reinforcement height and filler particle gradation on the interface friction characteristics between two kinds of three-dimensional reinforcement with dentied plastic/warp knitted geogrid and sand filler was studied.The results show that the peak shear stress and shear strength parameters increase gradually with the increase of overlying load,while the friction coefficient decreases gradually.The peak shear stress,shear strength parameters,quasi-friction coefficient and drawing coefficient increase with the increase of the height of the reinforcement.For the four particle gradations tested in this paper,the average particle size d50 has a good linear correlation with the ultimate drawing force of the denti-reinforcement.(3)Based on the upper bound analysis method and referring to the failure mode of Prandtl foundation bearing capacity,the calculation model of ultimate pullout force of geogrid reinforced structure with teeth considering the actual buried depth is established,and the corresponding calculation formula is derived.The reliability of the model is verified by comparing with the existing research results. |
