Shear strength and meso-pore characteristic of saturated compacted loess

Abstract

Abstract With the increasing demand for filling engineering construction in the Loess Plateau, the engineering problems related to saturated loess caused by rainfall and irrigation are also increasingly prominent. This work studied the shear characteristics of saturated compacted loess by experiments, and qualitatively and quantitatively explained the meso-mechanism of the effect of compaction degree on the shear characteristics combined with the meso-pore characteristic parameters. The study shows that the stress–strain curve of saturated loess under 80 and 85% compaction degree is strain softening, it is strain weak softening under 90% compaction degree, and strain hardening under 95% compaction degree. The failure strength and pore water pressure have a good fitting linear relationship with compaction degree, and the fitting correlation coefficients are more than 0.97. Under 95% compaction degree, the pore water pressure increases with the development of axial strain, then decreases after the peak, and may appear negative. With the increase in compaction degree, the micro and small pore content of the saturated loess soil increases, the medium, large and super large pore content decreases, the proportion of pore area decreases, the pore shape becomes uniform and smooth, the complexity of pore shape decreases, the pore arrangement tends to be regular and neat, and the directionality increases. The research results can provide references for engineering design, construction, and numerical calculation of filling engineering in loess area.