海底麻坑内外土体物理力学特性差异研究

Study on the differences in physical and mechanical properties of soil inside and outside a seabed pockmark

为了研究海底麻坑内外土体物理力学特性的差异,以杭州湾口外软土海底发现的大型麻坑为研究对象,分别在麻坑内外进行了4站15m孔压静力触探(CPTU)测试、2口钻孔共48个柱状样样品的常规土工试验,结果表明麻坑内土体相较麻坑外土体抗剪强度高、压缩模量大,饱和度、孔隙率和含水量低,而浅层气在海底土体中的赋存形式是造成这种差异的主要原因。

To analyze the differences in the physical and mechanical properties of soil inside and outside a pockmark, a 15-m pore pressure cone penetration test at four stations and the borehole column geotechnical test at two stations were conducted. The results showed that the soil phase in the pockmark had a higher shear strength, higher compressive modulus, lower saturation, porosity, and lower water content than those outside the pockmark. The occurrence of shallow gas in the subsea soil was the main reason for this difference.