Based on the microphysics of deep-sea sediment, preparation of simulated sediment with bentonite, diatomite and water as principal ingredients was proposed and vane shear tests were carried out to investigate the shear properties of the simulated sediment with different formulations. Based on tests, a shear characteristic curve of the stress and rotation was obtained from the macroscopic view. Based on the theory of particle flow and contact bonding model, a particle flow model of sediment with the characteristics of high porosity ratio, high water content and cohesive force was established, and a shear characteristic curve of the stress-rotation was obtained by numerical simulation of the vane shear test from mesoscopic point of view. Results show that the simulated sediment also has the low shear strength and shear thinning properties, similar to the deep-sea sediment, and the numerical simulation curve is consistent with the experimental curve, which verifies the correctness of the particle flow model and the numerical simulation method. The exploration of mesoscopic parameters of the sediment indicates that the bond strength determines the macroscopic shear strength, which provides a solid foundation for test on the walking performance of seabed mining vehicle and the mesoscopic study of the shear properties of deep sea sediment.%基于深海沉积物的微观物理性质,提出以膨润土、硅藻土和水等物料为主成分的模拟沉积物配方,配制了与深海沉积物相似的模拟沉积物,并开展其十字板剪切实验,从宏观上获得其应力-转角的剪切特性曲线.基于颗粒流理论,采用接触粘结模型,构建了具有高孔隙比、高含水率和粘聚力等特性的沉积物颗粒流模型,开展其十字板剪切过程数值模拟,从细观上获得其应力-转角的剪切特性曲线.研究表明,模拟沉积物具有与深海沉积物相同的极低剪切强度和剪切变稀特性,其剪切特性的细观数值模拟曲线与宏观实验曲线吻合,验证了粘性的沉积物颗粒流模型和数值模拟方法的正确性,探明了沉积物颗粒的细观参数,表明粘结强度决定沉积物宏观的剪切强度,为海底采矿车行走性能实验和从细观层面研究深海沉积物剪切特性提供了坚实基础.
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