Analysis On Tensile Behavior Of Triaxial Geogrid Reinforced Sand Under Tension With Different Loading Directions

Geogrid is a main kind of geosynthetic material with strong strength,good toughness,strong bearing capacity,high tensile strength,corrosion resistance,anti-aging,large friction coefficient,convenient construction and long service life.It is widely used in highways,railways,water conservancy,airports,municipalities and other fields.In the engineering with complex terrain and structure,the direction of the reinforced soil is not clear,which easily affects the strength of the geogrid,and thus poses a major safety hazard to the quality of the reinforced soil.As a new type of reinforced material,the triaxial geogrid has better performance than the biaxial geogrid,but there are few studies on the triaxial geogrid.In order to study the tensile behavior of the triaxial geogrid under different loading directions,the numerical analysis on the triaxial geogrid reinforced sand was done based on the test results of model pullout test.The numerical model of biaxial geogrid reinforced sand was also simulated for the comparison purpose.Meanwhile,the factors such as normal stress,relative density,and types of geogrid on the tensile behavior of geogrid reinforced sand were investigated.The simulation results show that:(1)Before the biaxial and triaxial geogrid stress reached the peak value,the relationship of stress-strain the geogrid followed a clearly linear relationship.The stress-strain curve is approximately straight.The deformation was elastic.(2)The normal stress has a great influence on the peak drawing stress of the biaxial and triaxial geogrid and the drawing friction coefficient on the interface.As the normal stress increases,the peak drawing stress of the geogrid increases,and the drawing friction coefficient decreases with the increase of the normal stress,and when the normal stress is small,The coefficient of friction reduction is large,and under high normal stress,the magnitude of the decrease in friction coefficient becomes small.(3)Compared with the biaxial geogrid,the peak pull-out stress of the triaxial geogrid under various influencing factors and the drawing friction coefficient on the interface are large,and the tensile stiffness distribution of the three-way geogrid in each tensile direction Also more uniform,the performance of the three-way geogrid is better than that of the biaxial geogrid.(4)The tensile direction and the grating type have little influence on the peak drawing stress of the geogrid and the friction coefficient on the interface,but have a great influence on the tensile stiffness of the geogrid.(5)The different degree of compaction of sand has little effect on the peak drawing stress of the geogrid,the drawing friction coefficient on the interface and the tensile stiffness of the geogrid.