Abstract Two important engineering design parameters, namely, dynamic energy dissipation and fragment size distribution, are closely associated with the crushing efficiency of the frozen soil in the cold regions. The crack distribution inside the frozen soil exerted a notable effect on its mechanical properties and energy dissipation characteristics under dynamic loads. In this study, a conventional split Hopkinson pressure bar with 50 mm diameter was used to conduct uniaxial impact compressive test in the frozen soil under different pre-existing crack conditions. The effects of pre-existing cracks on the energy dissipation and fractal dimension of the frozen soil were investigated based on the relationship among the energy absorbency rate, fractal dimension, and dynamic peak strength. The experimental results showed that energy absorbency rate and fractal dimension decreased as the growth of the number of pre-existing cracks, while both the energy absorbency rate and fractal dimension of frozen soil specimen with pre-existing cracks at the end surface remained less than those at the side surface. The effect of crack length on the energy absorbency rate and fractal dimension was larger than compared to the number and obliquity of cracks. In addition, the energy–time curves under different test conditions were also compared. Finally, the adaptability of the constitutive model was verified by comparing the theoretical and experimental curves based on the energy dissipation results.

中文翻译：

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单轴压缩冲击载荷作用下预存裂纹冻土的吸能特性及理论分析

摘要 动能耗散和碎片粒度分布两个重要的工程设计参数与寒冷地区冻土的破碎效率密切相关。冻土内部的裂缝分布对其动态载荷下的力学性能和能量耗散特性产生显着影响。在本研究中，采用直径为 50 mm 的传统分体式霍普金森压力杆在不同的预先存在的裂缝条件下对冻土进行单轴冲击压缩试验。基于能量吸收率、分形维数和动态峰值强度之间的关系，研究了预先存在的裂缝对冻土能量耗散和分形维数的影响。试验结果表明，吸能率和分形维数随着预存裂缝数量的增加而降低，而端面预存裂缝冻土试样的吸能率和分形维数均小于在侧面。裂纹长度对能量吸收率和分形维数的影响大于裂纹的数量和倾斜度。此外，还比较了不同测试条件下的能量-时间曲线。最后，基于能量耗散结果，通过比较理论曲线和实验曲线，验证了本构模型的适应性。而端面已有裂纹的冻土试样的吸能率和分形维数均小于侧面。裂纹长度对能量吸收率和分形维数的影响大于裂纹的数量和倾斜度。此外，还比较了不同测试条件下的能量-时间曲线。最后，基于能量耗散结果，通过比较理论曲线和实验曲线，验证了本构模型的适应性。而端面已有裂纹的冻土试样的吸能率和分形维数均小于侧面。裂纹长度对能量吸收率和分形维数的影响大于裂纹的数量和倾斜度。此外，还比较了不同测试条件下的能量-时间曲线。最后，基于能量耗散结果，通过比较理论曲线和实验曲线，验证了本构模型的适应性。还比较了不同测试条件下的能量-时间曲线。最后，基于能量耗散结果，通过比较理论曲线和实验曲线，验证了本构模型的适应性。还比较了不同测试条件下的能量-时间曲线。最后，基于能量耗散结果，通过比较理论曲线和实验曲线，验证了本构模型的适应性。