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Dynamic compressive properties of dry and saturated coral rocks at high strain rates
Engineering Geology ( IF 7.4 ) Pub Date : 2020-07-01 , DOI: 10.1016/j.enggeo.2020.105615
Linjian Ma , Jiawen Wu , Mingyang Wang , Lu Dong , Houzhen Wei

Abstract Coral rock is characterized by a high porosity of 48.51 ± 5.43% and a low compressive strength of 9.91 MPa due to its biological origin. To experimentally investigate the uniaxial compressive behaviors of both air-dried and fully saturated coral rocks, the quasi-static and dynamic compression tests were performed employing an electro-hydraulic servo-controlled device and a split Hopkinson pressure bar (SHPB) apparatus. The combined effects of strain rate and water saturation on the mechanical properties of coral rock were assessed in terms of the uniaxial compressive strength, Young's modulus, brittleness, energy dissipation as well as the failure pattern. The dynamic uniaxial compressive strength and Young's modulus of saturated coral rocks is consistently lower than those under dry condition, while the losses in them reduces with an increase in stain rate. The coral rock behaves in a more brittle manner in dry state than in saturated state, which is validated by the digital image correlation (DIC) in conjunction with high-speed camera images. Likewise, the change in brittleness or specific energy absorption (SEA) with strain rate under dry and saturated conditions exhibits a similar trend to the dynamic compressive strength. Furthermore, the dynamic failure of dry coral rock appears to be more dependent on the inherent flaws and defects than the saturated one, as the failure pattern doesn't follow a fixed shearing or splitting fracture mode. Overall, the difference of dynamic behaviors between dry and saturated coral rocks are mainly controlled by the coupling weakening and strengthening effects induced by free water. The strengthening effect of water saturation is manifested by making the strength and deformability of coral rock more sensitive to the loading strain rate.

中文翻译:

高应变率下干燥和饱和珊瑚岩的动态压缩特性

摘要 珊瑚岩由于其生物成因具有48.51±5.43%的高孔隙度和9.91 MPa的低抗压强度的特征。为了对风干和完全饱和珊瑚岩的单轴压缩行为进行实验研究,采用电液伺服控制装置和分体式霍普金森压力棒 (SHPB) 装置进行了准静态和动态压缩测试。从单轴抗压强度、杨氏模量、脆性、能量耗散以及破坏模式方面评估了应变率和水饱和度对珊瑚岩力学性能的综合影响。饱和珊瑚岩的动态单轴抗压强度和杨氏模量始终低于干燥条件,而随着染色率的增加,它们的损失会减少。珊瑚岩在干燥状态下比在饱和状态下表现得更脆,这通过数字图像相关性 (DIC) 结合高速相机图像进行了验证。同样,在干燥和饱和条件下,脆性或比能量吸收 (SEA) 随应变速率的变化表现出与动态抗压强度相似的趋势。此外,与饱和珊瑚岩相比,干珊瑚岩的动态破坏似乎更依赖于固有的缺陷和缺陷,因为破坏模式不遵循固定的剪切或分裂断裂模式。总体而言,干燥和饱和珊瑚岩之间动力行为的差异主要受自由水引起的耦合减弱和增强作用控制。
更新日期:2020-07-01
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