Insight into the Crushing Strength of Rockfill Grains at Different Temperature and Relative Humidity Conditions

The degradation of rockfill materials in certain surrounding environments is directly related to the deformation of many important geotechnical structures. This study aims to systematically reveal the effects of temperature and relative humidity on the crushing strength of rockfill materials at the particle scale. To this end, a series of single-particle crushing tests with controlled temperatures and relative humidities were carried out on rockfill grains. A crushing strength model, by combining an analytical solution and the Weibull statistics, was then proposed to predict the particle size and the environmental factors on the characteristic crushing strength of rockfill grains. The effects of temperature and relative humidity on the crushing strength were captured in the analytical solution by establishing the corresponding relationship between intensity criterion and energy criterion based on the fracture mechanics of idealized brittle solids. The Weibull statistics was adopted in the model to consider the influence of the random defects on the scale effect of crushing strength. The performance of the proposed model was verified by the experimentally obtained relationship between the characteristic strength and the average particle size at different temperature and relative humidity conditions. The result of this study provides a grain-scale insight into the water weakening or thermal weakening behavior of rockfill materials, as well as a quantitatively approach to consider the effects of particle scale and environmental factors in constitutive modeling of rockfill materials.