Microstructure and Macromechanical Properties of Retaining Structure of Near-Water Reinforced Soil under Dry-Wet Cycle

Abstract

Reinforced soil-retaining structures that have been working in near-water environments for a long time are likely to affect their own mechanical properties due to the dry-wet cycle caused by changes in water level. In response to this problem, this paper uses a combination of macro- and microtests, selecting reinforced soil samples with four water content conditions, five overburden pressure conditions, three sets of dry-wet cycle conditions, and a total of 60 working conditions for testing. Scanning electron microscopy was used to observe the microscopic characterization of the reinforced soil particles under different times of the dry-wet cycle, and the pull-out test was used to study the mechanical properties of the interface of the reinforced materials and soils. The analysis results of the test show that the dry-wet cycles increase the porosity of the reinforced soil and the number of pores, among which the proportion of micro and small pores increases, the abundance and fractal dimension of reinforced soil particles increase, and the roughness of the particle surface is reduced. The change of the microstructure of the reinforced soil causes the cohesion of the soil to decrease in the macroscopic view. The friction coefficient and the ultimate pull-out force of the interface between the reinforced materials and the soils decrease with the increase of times of dry-wet cycle.