东太平洋多金属结核研究区海底沉积物土工特性研究

Geotechnical Characteristics of Seabed Sediments in the Study Area of Polymetallic Nodules in the East Pacific Ocean

对大洋50航次获取的大洋插管柱状沉积物样品进行了土工力学参数测试,统计分析不同深度沉积物的含水量、湿密度、贯入阻力、剪切强度等土工特性与其取样层位之间的关系,以及各特性指标之间的关系。结果表明:研究区表层沉积物的含水率介于215.10%~284.90%,压缩系数介于5.53~6.21 MPa~(-1),天然密度介于1.20~1.24 g/cm~3;表层沉积物呈流塑状态。研究区表层沉积物的贯入强度和抗剪强度,随深度的增加而增大,在距沉积物表面15 cm处,沉积物的抗剪强度迅速增大至18 kPa,在15 cm深度以下,抗剪强度增加趋于平缓,表明沉积物抗剪强度相对稳定;在表层沉积物30cm深处,抗剪强度最大达到28 kPa,贯入强度最大达到58.7 kPa。

The soil mechanics test was carried out on the ocean sediment samples collected in the 50 voyages of the ocean. The relationship between the geotechnical characteristics of the sediment at different depths, such as water content, wet density, penetration resistance, shear strength and so on, was statistically analyzed, as well as the relationship among the characteristic indexes. The results show that the surface sediments in the study area have the characteristics of high water content, high compressibility, low density and low strength, and they are in flow plastic state. The penetration resistance and shear strength of surface sediments in the study area increase with the increase of depth.At the area which 15 cm from the sediment surface, the shear strength of the sediment increases significantly to 18 kpa. Below the depth of 15 cm, the shear strength is in the high value area with little fluctuation.