Temperature is a key factor influencing the mechanical behavior of the static interface between marine silica sand (SS) and geogrid, which directly impacts the stability and bearing capacity of reinforced soil structures. Despite its importance, there is limited research on the temperature-dependent mechanical properties of the silica sand-geogrid (SG) interface. To address this, a self-designed temperature-controlled large-scale static shear apparatus was used to perform a series of static shear tests on the SG interface, utilizing marine SS particles ranging from 0.075 mm to 2 mm and testing temperatures ranging from -5 degrees C to 80 degrees C. The results revealed a non-linear relationship between shear strength and temperature: as temperature increased from -5 degrees C to 40 degrees C, shear strength decreased, then rose between 40 degrees C and 50 degrees C, before declining again beyond 50 degrees C. The sensitivity of interface shear strength to variations in normal stress remained low at both low and high temperatures. Moreover, the interface friction angle and cohesion showed temperature-dependent fluctuations, initially decreasing, then increasing, and finally declining again. These findings underscore the complex effects of temperature on SG interface mechanics and suggest that temperature must be carefully considered in evaluating the stability and performance of reinforced soil structures under varying environmental conditions.

The high-temperature climate, dynamic stress loading and soil particle dimension have non-negligible influence on the interface interaction between marine coral sand and polymer layer, which determines the stability of coral sand engineering facilities installed with polymers. However, currently, the relevant research is rare. In this paper, by using the self-developed large temperature-controlled interface dynamic shear apparatus, a series of cyclic shear tests were conducted on the interfaces between polymer layer and coral sand with the particle size range of 1 mm - 2 mm (S1 coral sand) and 2 mm - 4 mm (S2 coral sand) in the temperature ranging from 5 degrees C to 80 degrees C. The experimental results indicate that, from 5 degrees C to 60 degrees C, the peak shear strength, dynamic shear stiffness and damping ratio rise, while from 60 degrees C to 80 degrees C, the decline of the mechanical parameters occurs. Also, temperature has more significant influence on the dynamic mechanical properties of S1 coral sand interfaces than that of S2 coral sand interfaces. Additionally, except for 60 degrees C, the peak shear strength, dynamic shear stiffness and damping ratio of S1 coral sand interfaces is all higher than that of S2 coral sand interfaces in other test temperature.

There is a lack of research on the molecular interactions between clay minerals and geopolymers at the nanoscale, as well as the interfacial mechanism and mechanical behavior of geopolymers, as a highly promising sustainable soft soil reinforcement stabilizer (grouting reinforcement method). In this study, molecular dynamics simulations were used to reveal the interfacial characteristics and the molecular behavior of geopolymer stabilizers and clay minerals. Molecular models of two geopolymers (calcium aluminosilicate hydrate (C-A-S-H) and sodium aluminosilicate hydrate (N-A-S-H)) and two major minerals (montmorillonite and illite) in soft Hangzhou clays were developed. Then, the interfacial characteristics, interaction mechanisms and mechanical behaviors of different geopolymer/clay mineral interface systems were compared. It was found that montmorillonite and illite attract water molecules to aggregate on the mineral surfaces and promote the migration and diffusion of Ca2+ and Na+ at the interfaces. The interfacial interactions of the geopolymer/clay mineral system mainly consisted of electrostatic interactions. Stronger hydrogen bonding interactions occur at the interface of the geopolymer/clay mineral system. The metal cations and the geopolymer stabilizer between the clay mineral layers form a complex ion nest in concert with the aggregated water molecules to stabilize their interfacial interactions. In terms of the mechanical properties, the C-A-S-H stabilizer has a stronger interfacial shear strength. The shear strength of the illite system is stronger than that of the montmorillonite system, but montmorillonite can produce stronger interfacial bonding with the ground polymer stabilizer, and the curing effect is more obvious.