The soft-hard interbedded structure represents a key contributor to rock mass anisotropy. This study examines the dynamic response of such formations under blasting loading through impact tests on six soft-hard interbedded configurations and four groups of rock-like specimens with varying hard rock ratios. Systematic analysis was conducted on dynamic mechanical properties, energy dissipation characteristics, and failure mechanisms in these composite rock systems. Results demonstrate that: (1) Specimen peak stress exhibits progressive enhancement with increasing hard rock content ratio, while displaying a marginal declining trend as layer quantity increases. (2) Increasing hard rock content reduces the energy reflection coefficient while enhancing both the energy transmission coefficient and absorption rate. Conversely, greater layer thickness increases energy reflection but diminishes the transmission and absorption coefficients. Notably, specimens impacted from the hard rock side demonstrate lower reflection coefficients but higher transmission coefficients and absorption rates compared to those impacted from the soft rock side. (3) As the hard rock content increases, the specimens exhibit progressively reduced overall damage severity, with the predominant failure mode transitioning from multi-directional conjugate shear fractures to tensile splitting. Conversely, increasing the number of layers markedly amplifies the intensity of specimen damage.

To further investigate the influence of surrounding rock mass damage on the rock burst mechanism, material selection for simulating the damage zone was carried out, and a test piece containing the damage zone (1000 mm×600 mm×400 mm) was fabricated. Using the self-developed rock burst model test system′s drilling device, caverns were excavated in the specimens(with a hole diameter of 110 mm). Rock burst model tests were then conducted on specimens with varying damage zone thickness through step loading, considering the damage effects on the surrounding rock. During the tests, cameras monitored the damage process of the tunnel wall. Image expansion was performed based on the rubber paper model principle, and the box dimension of the expanded image was calculated and analyzed. The results show that the macro-failure process of a rock burst consists of crack initiation, particle ejection, crack propagation, and debris avalanche stages. As the thickness of the damage zone increases, the failure depth of the specimen chamber′s side wall gradually increases. In the stage of slow increase and sharp increase in the box dimension of the left and right tunnel walls, the growth rate of the box dimension decreases linearly with the increasing thickness of the damage zone. With the increase in damaged zone thickness, cracks in the tunnel wall primarily concentrate within the damaged zone during loading, and the damage depth of the tunnel wall increases when the cavity is damaged. The findings further elucidate the breeding and failure mechanism of rock bursts in deep-buried caverns under the condition of surrounding rock damage.

The presence of joint fractures significantly influences the dynamic performance of the rock mass. To investigate the effects of joint angles and filling materials on the dynamic response of filling joint samples under impact loading, a series of impact tests were conducted using a split Hopkinson pressure bar (SHPB). Samples with seven different joint angles and three types of filling materials were tested. The relationships between dynamic characteristics, energy dissipation, joint angles, and properties of the filling material were systematically analyzed. The results indicate that:(1) The stress-strain curves of the joint samples of different filling media are significantly different. The stress-strain curves of sediment and lime filling samples show plastic failure characteristics at joint angle α≤45° and brittle failure at joint angle α>45°, while gypsum filled samples primarily display brittle failure, except at joint angle α=45°, where plastic failure occurs due to stress wave propagation effects. (2) The dynamic compressive strength of joint samples with the same filling material initially decreases and then increases with the increasing joint angle α, reaching a minimum value at α=45°. Among the three filling materials, gypsum-filled joints exhibit the highest compressive strengths. (3) Energy dissipation characteristics vary with joint angle. The reflected energy ratio increases initially and then decreases, peaking at α=45°, while the transmitted and absorbed energy ratios decrease initially and then increase, reaching their lowest values at α=45°. These findings provide critical insights into the dynamic behavior of jointed rock masses and have practical implications for engineering applications involving impact or blast loading.