Shear creep parameters of simulative soil for deep-sea sediment

MA Wen-bo(马雯波), RAO Qiu-hua(饶秋华), LI Peng(李鹏), GUO Shuai-cheng(郭帅成), FENG Kang(冯康)

(School of Civil Engineering, Central South University, Changsha 410075, China)

Abstract:Based on mineral component and in-situ vane shear strength of deep-sea sediment, four kinds of simulative soils were prepared by mixing different bentonites with water in order to find the best simulative soil for the deep-sea sediment collected from the Pacific C-C area. Shear creep characteristics of the simulative soil were studied by shear creep test and shear creep parameters were determined by Burgers creep model. Research results show that the shear creep curves of the simulative soil can be divided into transient creep, unstable creep and stable creep, where the unstable creep stage is very short due to its high water content. The shear creep parameters increase with compressive stress and change slightly or fluctuate to approach a constant value with shear stress, and thus average creep parameters under the same compressive stress are used as the creep parameters of the simulative soil. Traction of the deep-sea mining machine walking at a constant velocity can be calculated by the shear creep constitutive equation of the deep-sea simulative soil, which provides a theoretical basis for safe operation and optimal design of the deep-sea mining machine.

Key words:shear creep parameter; simulative soil; deep-sea sediment; shear creep test; Burgers model