Study of Wetting Behaviors of Gravel Soil Based on Specific Fracture Energy

ABSTRACT In many engineering applications such as dams, tunnels, and mines, soil is often affected by groundwater, resulting in various geological disasters, such as landslides and collapse of goaf. The deformation that occurs when rocks and soil are immersed in water without applying external loads is defined as wetting deformation; therefore, it is crucial to studying the wetting deformation of gravel soil when encountering water. At high stress levels, the wetting deformation is mainly attributed to reducing particle breakage strength caused by the wetting. This study conducted a series of loading tests on dry and wet limestone particles and obtained the distribution of specific fracture energy of gravel soil particles with different particle sizes before and after wetting. The variation of specific fracture energy after particle wetting was used for assessment of particle breakage strength. This study improved the cumulative distribution model of particle specific fracture energy by adding morphology parameter β. The improved model solves the problem of large deviation in the initial curve segment of the original model and is more suitable for fitting experimental data of single-particle crushing test. And the test results indicate that particles’ specific fracture energy is significantly related to their particle size. As the particle size increases, the specific fracture energy of particles decreases. After wetting, the maximum specific fracture energy Em,max and median specific fracture energy Em50 of the limestone particles after wetting decrease to varying degrees. Compared with Em50, the decrease in Em,max is more significant, meaning that water reduces the energy required for the limestone fracture process and causes homogenization of the limestone.