Similarity Evaluation of Transparent Sand and Natural Sands Based on Simulation of a Hypoplastic Constitutive Model

In transparent soil model experiments, fused quartz stands out as the most promising substitute for natural sand. However, there is still a lack of a comprehensive evaluation system to assess the similarity of its mechanical properties to natural sand. Therefore, a similarity evaluation method based on constitutive model simulation is proposed. First, due to the high friction angle characteristic of fused quartz in transparent soil model tests, multiple oedometer compression and shear box tests were conducted on various gradations of fused quartz. Subsequently, a hypoplastic sand model, which is abundant in natural sand data, stable, and has a straightforward calibration process, was then selected for parameter calibration of fused quartz. Finally, the substitutability of fused quartz for natural sand was evaluated by comparing constitutive parameters and shear box simulation, considering factors such as initial void ratio and confining pressure. The results indicate that the hypoplastic sand model accurately captures the shear behavior of fused quartz. Particles with grain sizes ranging from 0.5 to 2 mm weaken the strength of well-graded fused quartz. The findings also suggest that well-graded fused quartz maintains consistent shear behavior with various natural sands. By contrast, the applicability of single-sized fused quartz is limited.