Analysis of triaxial shear properties of mudstone coarse-grained soils considering penetrating erosion effects

Abstract

This investigation aims to elucidate the effects of penetrating erosion on the triaxial shear properties of mudstone coarse-grained soil (MCGS). The consolidated drained (CD) triaxial tests were conducted on medium-strong weathered siliceous MCGS specimens treated by various penetrating erosion stresses, comparing them with untreated specimens. The main outcomes are as follows: First of all, as the escalation of penetration erosion stress, peak shear strength diminishes, shear deformation intensifies, and the improved relative breakage potential B_r* of particles escalates, the critical state line rotates downward in the p − q plane, while it shifts downward in the e − (p/p_a)^ξ space. Meanwhile, the MCGS specimens treated by penetration erosion exhibit pronounced deterioration characteristics, and those variations induced by changes in penetrating erosion stress are more significant at low confining pressures, while these differences diminish progressively with increasing confining pressure. In addition, the structural stability of MCGS specimens was greatly affected by penetration erosion and dictates the susceptibility of MCGS to particle breakage, which in turn influences the triaxial shear features of MCGS. Furthermore, the equivalent correspondence between particle breakage and critical state under different treatments of penetration erosion enables the normalization of these test patterns, providing a foundation for developing a constitutive model that uniformly accounts for the influence of penetration erosion.