Yuanyou Xia

Blast-induced seismic waves and air-shock overpressures pose substantial threats to the structural integrity and safety of adjacent buildings. Due to stringent experimental requirements and complex theoretical modeling, accurately characterization the blasting response patterns and detailed time-frequency characteristics remains a notable challenge. Vibration monitoring experiments shows that blast vibrations have obvious directional differences and frequency selectivity in amplitude and time-frequency distribution. The longitudinal and tangential components exhibit a remarkable elevation amplification, while the vertical component fluctuates periodically. Vibration amplitude decreases with increasing blast-source depth. The time-domain responses and high-frequency components distributions are primarily governed by the floor elevation. As blasting vibrations propagate from the ground into buildings, the dominant frequency (DF) decreases and vibration energy shifts toward the lower frequency bands. Subsequently, a kinematic model for wall structures is established. Wall deflection decreases with increasing elastic modulus and wall thickness, with a gradually diminishing reduction rate; by contrast, deflection increases nearly linearly with applied pressure. Degraded structural constraints and prolonged loading duration intensify damped-vibration responses and amplify structural deflections. Numerical simulation results show that wall damage caused by air shock wave is dominated by horizontal cracks propagating along mortar joints, exhibiting a dispersed failure pattern; in comparison, seismic waves trigger additional diagonal and vertical cracks. Damage evolution is further affected by pre-existing cracks and window openings.

The long-term dynamic characteristics of calcareous sand foundations under cyclic wave loading are directly related to the service safety of facilities such as artificial island revetments. Accordingly, drained cyclic triaxial tests with constant confining pressure were conducted on K0-consolidated saturated calcareous sand to investigate the long-term dynamic response. The effects of initial mean stress (p0), initial static stress ratio (ηc), cyclic stress ratio (ζ), and relative density (Dr) on the dynamic response characteristics were systematically studied, including the accumulated axial strain (εacc 1), accumulated axial strain rate ( ), accumulated volumetric strain (εacc v), accumulated volumetric strain at the phase transformation (εacc v,p), accumulated deviatoric strain (εacc q), and particle breakage. The test results indicate that: (1) With increasing ζ and ηc, εacc 1 increases significantly, whereas an increase in Dr effectively suppresses its development; the influence of p0 on εacc 1 is relatively limited. (2) Under the tested conditions, both εacc 1 and exhibit an evolutionary characteristic of rapid development initially followed by gradual stabilization. (3) εacc v undergoes three distinct stages: initial contraction, phase transformation, and stable dilation. An empirical formula linking εacc v,p to ζ, p0, and the void ratio (e) was proposed. Furthermore, the phase transformation state line (PTSL) was established in the e-(p/pa)0.7 plane. Its position depends strongly on the initial void ratio (e0), and it lies below the critical state line (CSL). (4) εacc q far exceeds εacc v, indicating that εacc q dominates long-term accumulated deformation. (5) Significant particle breakage did not occur under the simulated test conditions; instead, cyclic wave loading primarily induced inter-particle rearrangement and fabric adjustment. (6) Finally, an explicit prediction model for εacc 1 was developed, whose predictions agree well with measured data.

Liquid carbon dioxide (L-CO ₂ ) fracturing is recognized as an eco-friendly rock excavation technique. However, the lack of experimental evidence has limited quantitative evaluation of its advantages on shock wave and vibration control. Therefore, comparative experiments were conducted with monitoring the shock wave overpressure and vibration velocity. The results demonstrate that: (1) the overpressure and vibration induced by L-CO ₂ fracturing are significantly lower than those generated by emulsion explosive; (2) the L-CO ₂ overpressure curve can be divided into four phases: exponential rise, oscillatory decay, negative pressure zone, and multiple bubble pulsations; (3) the L-CO ₂ pulse exhibits lower peak overpressure, longer rise and decay times, and wider pulse width; (4) L-CO ₂ fracturing produces a higher proportion of medium- and large-sized fragments, with energy predominantly distributed in low-frequency bands, leading to slower vibration attenuation, greater dynamic response factor, and smaller damping ratio in engineering structures; and (5) barrier holes mitigate vibration with a reduction of up to 7.26%, and phenomena such as concentration, diffraction, and barrier effects can be observed around these holes. The successful application of L-CO ₂ fracturing technology in this reef removal project near buildings provides preliminary evidence supporting its feasibility and safety.

To investigate the dynamic characteristics, energy dissipation patterns, and failure modes of granite with filled joints of varying thicknesses under impact loading, we utilized the Split Hopkinson Pressure Bar (SHPB) test setup for impact tests on both unfilled and filled granite samples. Additionally, a high-speed camera was used to capture the dynamic failure and crack propagation processes of the rock samples in real time. The results indicate that the thickness of the filling material significantly affects the stress–strain behavior of jointed rock masses, particularly in terms of characteristics of stress variation and post-peak morphology. In comparison to unfilled jointed rock samples, a distinct “stress bimodal” phenomenon is present, and the rebound of strain following the peak gradually decreases. The fracture patterns observed in the jointed rock samples are primarily characterized by tensile failure. Damage is notably more pronounced on the left side of the samples (near the incident bar), the lower side, and in the areas filled with gypsum. The most severe degree of damage occurs when the filling thickness is 7.56 mm. As the thickness of the filling increases, the dynamic compressive strength of the rock mass diminishes, and the peak strain first increases and then decreases. Concurrently, the energy reflection coefficient of the rock mass increases linearly, while the energy transmission coefficient declines linearly. Furthermore, the energy dissipation ratio first increases and then decreases. The test data reveal that the critical filling thickness influencing the dynamic properties, energy absorption characteristics, and damage degree of jointed rock samples falls within 4.91 mm to 7.56 mm.

Shallow-buried cavities and underground structures are inevitably subjected to transient perturbation from earthquakes or engineering activities during their life circle, leading to the occurrence of dynamic failure. The investigation presented by this paper concentrates on the dynamic responses triggered by an aperiodic transient [ ] wave around a circular lined tunnel with an imperfect interface in a half-space and the spring model is employed to describe the interface between rock mass and liner. Resorting to the wave function expansion scheme, the large arc assumption, the Graf’s addition theorem and the numerical inversion algorithm of Laplace transformation, the dynamic responses around a circular shallow lined tunnel with an imperfect interface are evaluated theoretically. The good agreement of time–history curves and contour snapshots for stress between the theoretical solutions and the numerical counterparts validates the analytical scheme. The effect of disturbance direction, embedment depth, thickness of liner and interface coefficients on the dynamic responses around the shallow-buried lined tunnel is analyzed. The results indicate that the positions of peak hoop dynamic stress concentration factor (DSCF) are approximately perpendicular to the perturbation direction. The DSCF distributions converge to be stable when the ratio of embedment depth to excavation radius exceeds 10.0. The thickness of the liner mainly affects the dynamic responses around the interface. Increase of elastic coefficient induces a decreasing DSCF in rock mass and an increasing counterpart in the liner. The results may provide the theoretical basis for the transient responses and aseismic design of underground tunnels.

Based on practical construction experience, it is observed that a significant number of rockburst-prone regions exhibit structural surfaces of varying scales that exert a controlling influence on rockburst. Therefore, it is crucial to review the progress and hotspots in research on structure rockburst from a macroscopic perspective. This paper utilized CiteSpace software to summarize the references on structure rockburst research from the Web of Science Core Collection database from 2003 to 2022. The results include keyword cooccurrence and evolution analysis, and co-citation and cluster analysis. Through the in-depth analysis of structure rockburst literature, the research progress of structure rockburst in indoor experiments, numerical simulation, and on-site micro-seismic monitoring progress, the development trend and research hotspots were evaluated, and the current structure rockburst was discussed. The shortcomings of current research on structure rockbursts are discussed, and future development directions are proposed from the perspectives of structure rockburst mechanism, prediction and prevention measures.