红岗新河流域粉砂岩物化作用下循环加卸载力学劣化试验研究OA

To investigate the impact of water quality on the mechanical degradation of underlying siltstone in the Honggang New River Basin,mechanical loading and unloading tests were conducted under two physicochemical factors—wet-dry cycles and saline solution concentration—using indoor mechanical testing equipment.The stress-strain curves,mechanical characteristic parameters,and microscopic features of the specimens were analyzed.The study revealed that the stress-strain curves of siltstone specimens exhibit a"memory effect,"remaining unaffected by physical and chemical factors,which only alter the amplitude of loading and unloading cycles.The mechanical degradation effect of saline concentration gradually intensifies,while the wet-dry effect remains relatively balanced.As the physicochemical influence strengthens,irreversible deformation increases during the loading and unloading process of siltstone,and the elastic modulus decreases.Microscopically,physicochemical effects alter the formation path of failure fractures,while macroscopically,they lead to reduced stress levels.The stronger the physicochemical effect,the lower the fractal dimension of the specimens,resulting in more regular and orderly formation of failure fractures.These findings provide insights into the evolution of cyclic loading and unloading mechanical characteristics of siltstone specimens under physicochemical coupling effects.