Study On Structural Characteristics Of Tenon Geogrids And Its Reinforcement Mechanism Of Coarse Grained Soil

Tenon geogrid is a new type of geosynthetic material.It has a mesh structure and a tenon structure.The tenon structure can provide greater friction resistance than traditional geogrids.At present,the research on reinforced soil is mainly based on indoor model test and field test.Due to the complexity of the interaction between reinforced soil,the research on the reinforcement mechanism has not formed a set of systematic theories,which limits the development of reinforced soil technology to a great extent.This paper takes the interfacial characteristics of tenon geogrid and coarse grained soil as the main research object,and conducts pull-out tests of tenon geogrid and tenon-less geogrid in different coarse grained soils to analyze and compare whether there is.The influence of tenon structure on the characteristics of the reinforcement-soil interface;FLAC3D finite element software is used to analyze and compare the influence of the different structural characteristics of tenon geogrids on the interface between the reinforcement and soil,and the PFC3 D discrete element software is used to study the tenon geogrid from a meso-level perspective.Pull-out test between grid and coarsegrained soil and the interaction mechanism between reinforcement and soil.The research in this paper will help to further improve the understanding of the interaction between reinforcement and soil,and draw the following understanding:(1)Through the indoor pull-out test,the shear stress of the tenon grating is increased by11.7% ～ 36.9% compared with that of the non-tenon grating.The contribution of the tenon structure to the interfacial cohesion is about 2.04 k Pa～5.13 k Pa,and the contribution to the interfacial friction angle is about 1.61°～2.25°。(2)The numerical simulation of the structural characteristics of tenon geogrid shows that:with the increase of tenon thickness,the interface strength of reinforcement and soil is improved,and the effect of interface strengthening is better in the filler with smaller soil particles;with the increase of tenon side length,although the interface strength is improved,the interface strength calculated according to the area of reinforcement is reduced,and the joint tenon and middle tenon are the same With the increase of grid size,the interface strength calculated according to the area of reinforcement gradually increases,and the interface friction coefficient of 250 mm × 200 mm grid size is the largest.(3)The numerical simulation analysis of tenon geogrid and coarse grained soil pull-out test from meso perspective shows that the tensile force inside the geogrid decreases obviously at the first transverse rib and tenon;and the soil stress is also in the first transverse.The ribs are concentrated,and there is obvious dilatancy behavior at the interface between the reinforcement and the soil;the initial drawing resistance is mainly borne by the tenon resistance and the friction resistance,and then the friction resistance and the cross-rib resistance.The tenon grid is better than the tenon-less.The shear stress of the grid increases by 11.7%～36.9%;the pullout resistance increases with the increase of the particle size of the soil particles,but the increase rate decreases.