Influence of wet-dry cycles on uniaxial compression behavior of fissured loess

The stability of slopes of China's Loess Plateau, where fissured loess is abundant, is affected by wet-dry cycles. Uniaxial compression tests and the PCAS system were used to analyze the development of visible cracks and mechanical behavior of fissured loess over wet-dry cycles. Results show that the wet-dry cycles and the fissure angle both influence the development of cracks in fissured loess samples. The failure of fissured loess samples manifests as four main modes such as fracture failure, slip-fracture failure, slip failure, and compression-shear failure. Wet-dry cycles had a negligible effect on the failure mode in samples with fissure angles of 0 degrees, 15 degrees, 45 degrees, and 60 degrees, but were more noticeable at fissure angles of 30 degrees and 90 degrees, ranging from compression-shear failure to fracture failure. The initial elastic modulus and uniaxial compressive strength of fissured loess both decline after wet-dry cycles. After various wet-dry cycles, the associations between uniaxial compressive strength and fissure angle all display a double-V shaped pattern, with abrupt shifts in 45 degrees-90 degrees and the minimum value at a fissure angle of 60 degrees. After wet-dry cycles, the uniaxial compressive strength of fissured loess decreases, while the amplitude of change decreases.