Compression characteristics of filled jointed rock under dry-wet cycles

In order to explore the effects of dry-wet cycles on the compressive mechanical strength and deformation and failure characteristics of filled jointed rock, the artificial jointed rock samples with various fillings were prepared and then pre-treated by 0 (drying state), 1, 5, 10, 15, and 20 dry-wet cycles, which resulted in certain cumulative damage. On this basis, static uniaxial compression tests and dynamic impact tests were carried out on filled jointed rock samples, and in the process of dynamic impact tests, the impact failure characteristics of filled jointed rock were observed with the help of a high-speed camera. Research results show that with the increase in the number of dry-wet cycles, the static and dynamic compressive strengths of the filled jointed rock continue to decrease, and the decrease rates gradually becomes smaller. After 20 dry-wet cycles, the total deterioration degree of the static and dynamic compressive strength of the rock samples is between 20% and 30%. The dynamic compressive strength reduction law of rock samples conforms to the exponential function distribution through fitting. With the increase in the number of dry-wet cycles, the static failure mode gradually develops from splitting failure to shearing failure. In the process of dynamic impact, the degree of fragmentation of filled jointed rock and the degree of smashing and spattering of the filled joint group are aggravated, verifying that the dry-wet cycles will seriously affect the deformation and failure characteristics and dynamic impact resistance of filled jointed rock. In addition, the stress wave transmission coefficient of the rock sample decreases continuously with the increase in the number of dry-wet cycles, and after 20 dry-wet cycles, the coefficient decreases by about 10%. It can be seen that the dry-wet cycle has a significant impact on the stress wave propagation ability.