Abstract:

Due to the complexity of the reinforced soil interface, the empirical methods are often used when laying geogrid in reinforced soil engineering construction, which largely causes the waste of geogrids and engineering safety hazards. Clarifying the influence range of the interfacial action of reinforced soil with different fillers is helpful to determine the reasonable reinforcement spacing of reinforced soil structures. In order to reveal the influence range of interface action between reinforcement and soil of different fillers, a series of pull-out tests was carried out with four types of sand and geogrid under different normal stresses. By combining with digital image measurement technology, the evolution laws of interfacial shear band thickness, particle displacement vector, peak pullout resistance, and strain of geogrid for different types of sand were analyzed. The results show that the thickness of interfacial shear band H increases with the increase of normal stress σ_v and the average particle size of sand d₅₀. Through the multivariate fitting method, the function expressions among the thickness of the interfacial shear band H, the normal stress σ _v and the average particle size of the sand d ₅₀ are obtained. In the pull-out process of geogrid, the displacement vector of sand particles is significantly different when the geogrid is taken as the boundary. The displacement vector of particles above the geogrid is significantly larger than that below the geogrid, and there is a concentration band of particle displacement vectors in a certain range above and below the geogrid. The peak pullout resistance increases with the increase of normal stress σ _v and the average particle size of sand d ₅₀. The geogrid strain of each section of different types of sand shows a decreasing trend from the front to the rear.

Key words: types of sand, pull-out test, geogrid strain, interface shear band, displacement vector