In order to understand the mechanical properties and energy dissipation law of frozen sandstone under impact loading, the cretaceous water-rich red sandstone was selected as the research object to conduct impact tests at different freezing temperatures (0°C, −10°C, −20°C, and −30°C). The test results suggested the following: (1) the peak stress and peak strain of frozen sandstone are positively correlated with strain rate and freezing temperature, and the strain rate strengthening effect and the low-temperature hardening effect are obvious. (2) The strain rate sensitivity of dynamic stress increase factor (DIF) is negatively correlated with temperature. Water-ice phase change and the difference in the cold shrinkage rate of rock matrix under strong impact loading will degrade the performance of rock together, so DIF is less than 1. (3) In the negative temperature range from −10°C to −30°C, DEIF is always greater than 1. The energy dissipation rate of red sandstone specimens fluctuated between 10% and 25% under the impact loading, and the data are discrete, showing obvious strain rate independence. The failure form changes from tensile failure to shear and particle crushing failure. (4) Combined with the micromechanism analysis, the difference in dynamic mechanical properties of red sandstone at different temperatures is caused by the water-ice phase change and the different cold shrinkage rates of the frozen rock medium. When the temperature drops from 0°C to −2°C, water migrates to the free space of the pore of frozen rock and freezes into ice crystal, resulting in frozen shrinkage. At −30°C, the expansion of ice dominates and the migration of water will stop, leading to frost heave.

中文翻译：

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冲击载荷作用下冷冻砂岩的力学性能和耗能研究

为了了解冷冻砂岩在冲击载荷下的力学性能和能量耗散规律，选择白垩纪富水红砂岩作为研究对象，在不同的冷冻温度（0°C，-10°C，- 20°C和-30°C）。试验结果表明：（1）冻结砂岩的峰值应力和峰值应变与应变率和冻结温度成正相关，应变率的强化作用和低温硬化作用明显。（2）动态应力增加因子（DIF）的应变率敏感性与温度呈负相关。在强冲击载荷下水冰的相变和岩石基体的冷收缩率差异会共同降低岩石的性能，因此DIF小于1。（3）在-10°C至-30°C的负温度范围内，DEIF始终大于1。在冲击载荷作用下，红砂岩样品的能量耗散率在10％至25％之间波动，数据为离散，表现出明显的应变率独立性。破坏形式从拉伸破坏变为剪切破坏和颗粒破碎破坏。（4）结合微观力学分析，红砂岩在不同温度下的动态力学性能差异是由水冰相变和冻岩介质的不同冷收缩率引起的。当温度从0°C降至-2°C时，水迁移到冻结岩石孔隙的自由空间并冻结成冰晶，导致冻结收缩。在−30°C，冰的膨胀占主导地位，水的迁移将停止，