Dynamic Behavior and Fatigue Damage Evolution of Sandstone under Uniaxial Cyclic Loading

Abstract

The mechanical response characteristics of sandstone specimens under different stress amplitudes and loading frequencies were tested by a TAW-2000 rock triaxial testing machine. The characteristics of the stress-strain curve and the evolution process of strain damage under cyclic loading are analyzed. Based on creep theory and the disturbance state concept, a theoretical model between the axial compressive strain, axial compressive stress, and cycle number is established. The results show that there exists an upper threshold value of stress in cyclic loading above which the specimen will be damaged. As peak stress increases, the energy loss and irreversible deformation caused by damage gradually increase. When loading to an unstable peak stress under cyclic loading, the fatigue damage of sandstone under cyclic loading undergoes three characteristic stages: the initial stage; the stable stage; and the accelerated failure stage. The parameters of the strain damage model based on the disturbance state concept of sandstone are identified by test data, and the rationality of the model is validated by comparing theoretical values with experimental measurements.

Energy and Fatigue Damage Evolution of Sandstone under Different Cyclic Loading Frequencies

“…An indoor test is an effective method to quantitatively measure rock deformation and failure. Researchers carried out uniaxial and triaxial cyclic loading and unloading tests on rock salt, sandstone, and marble under different confining pressures, stress amplitudes, and cyclic loading frequencies, respectively, to study the deformation law, strength characteristics, fatigue characteristics, damage evolution law, and damage accumulation model of rock [8][9][10]. In recent years, some scholars [11][12][13][14][15] studied the behavior of energy dissipation and release in the process of rock deformation and failure under uniaxial compression and revealed the evolution of volume energy, elastic energy, and dissipated energy during rock mass failure; subsequently, they obtained the characteristics of energy accumulation and dissipation before and after the peak compressive force.…”

Dynamic Behavior and Constitutive Relationship of Mudstone Slip Zone of Landslide with Weak Interlayer

“…In recent years, there have been an increasing number of studies on the dynamic deformation characteristics of rocks and soil [8][9][10][11]. Anupam et al [12] used fly ash and rice husk ash to investigate the deformation behavior of subgrade soil mixtures under repeated triaxial loading.…”

Energy dissipation and fatigue damage evolution of sandstone under different upper limit stresses

“…Under the action of cyclic load, rock material repeatedly accumulates and dissipates energy, and rock breaks down under the drive of energy (Liu et al 2012;Yin et al 2012;Xie et al 2005;Li et al 2018). In recent years, many scholars have studied the mechanical properties, fracture failure mechanism, and long-term stability of rocks from the perspective of energy, where some scholars studied the behavior of energy dissipation in the process of rock deformation under uniaxial compression and graded cyclic loading and unloading, proposed the calculation method of the total input energy of the specimen under each cyclic loading and unloading, and established the evolution equation of the dissipated energy (Wang et al 2019a, b;Wu et al 2020;Gong et al 2020;Sun et al 2020;Liu et al 2020). Other scholars studied the change of energy in cyclic loading by analyzing the area change of hysteretic curve, established the empirical equation of hysteretic energy, proposed the modified calculation method of energy parameters, and established the constitutive equation of stress-strain evolution curve under cyclic loading (Sun et al 2017;Du et al 2019;Yang et al 2017;Deng et al 2016;Sun et al 2020).…”

“…In recent years, many scholars have studied the mechanical properties, fracture failure mechanism, and long-term stability of rocks from the perspective of energy, where some scholars studied the behavior of energy dissipation in the process of rock deformation under uniaxial compression and graded cyclic loading and unloading, proposed the calculation method of the total input energy of the specimen under each cyclic loading and unloading, and established the evolution equation of the dissipated energy (Wang et al 2019a, b;Wu et al 2020;Gong et al 2020;Sun et al 2020;Liu et al 2020). Other scholars studied the change of energy in cyclic loading by analyzing the area change of hysteretic curve, established the empirical equation of hysteretic energy, proposed the modified calculation method of energy parameters, and established the constitutive equation of stress-strain evolution curve under cyclic loading (Sun et al 2017;Du et al 2019;Yang et al 2017;Deng et al 2016;Sun et al 2020). The above studies have a unified understanding of the energy conversion for rock materials: The work done by external force on rock is mainly converted into elastic energy and dissipative energy, most of the work done by external force before yield point is converted into elastic strain energy and stored in the rock sample, the dissipative energy increases slightly, the dissipative energy increases rapidly after yield point, and the growth rate of elastic energy slows down.…”