Abstract:

To study the shock compression behavior and equation of state of shallow coral reef limestone subjected to high-intensity dynamic loadings, we conducted plate impact tests using a one-stage gas gun technique at impact velocities ranging from 200 m/s to 500 m/s. Based on the particle velocity histories of samples free surface which were obtained by all-fiber displacement interferometer system for any reflectors, the interaction between the shock wave propagation and the evolution of internal pores was analyzed. The dynamic strength and the shock adiabatic relationship of shallow coral reef limestone under one-dimensional strain shock wave loading were determined. The results indicate that the shock wave expands into a two-wave configuration, comprising an elastic precursor wave and a deformation wave, within the tested samples. This phenomenon arises from irreversible plastic deformation mechanisms, including pore collapse and matrix slippage, under shock wave compression. The propagation speed and energy of deformation waves increase with rising impact pressure. The Hugoniot elastic limit value and dynamic yield strength of shallow coral reef limestone are 0.109±0.03 GPa and 0.074±0.02 GPa respectively under the strain rate range from 2.9×10⁴ s⁻¹ to 7.5×10⁴ s⁻¹.    A Hugoniot linear relationship for shallow coral reef limestone was established within the pressure range of 0.4 GPa to 1.2 GPa, and the corresponding pressure-specific volume curve exhibits distinct elastic and compaction stages. It is also found that compared with the shock adiabatic data of terrigenous porous limestone, the shallow coral reef limestone shows greater compressibility under intensive dynamic loadings. Eventually, the P-a QUOTE

Key words: rock dynamic mechanics, coral limestone, plate impact, pore evolution, shock response, equation of state