深圳湾吹填淤泥非线性压缩性及参数测定

Laboratory determination of nonlinear compressibility and parameters of dredged fill in Shenzhen bay

采用GDS固结试验系统对深圳湾吹填淤泥进行分级加载固结试验,对3种孔隙比与有效应力之间的非线性关系进行回归拟合,获取相应的拟合参数。结果表明：在6-400 kPa的固结压力下,吹填淤泥的压缩系数、体积压缩系数、压缩模量随孔隙比的减小呈现非线性变化,变化幅度达数十倍;压缩指数随孔隙比的减小而非线性减小,减小近1倍;在较小的第1级固结压力下吹填淤泥的压缩应变高达24.44%,占整个固结压力范围内累计压缩应变的一半以上;3种孔隙比与有效应力之间的非线性压缩关系对于深圳湾吹填淤泥都是适用的,其中孔隙比与有效应力之间的幂函数关系形式简单,拟合效果最好,适用性较强,可应用于吹填淤泥等超软土非线性与大变形固结性状数值分析与压缩特性研究。

Incrementally-loaded consolidation tests were performed on dredged fill in Shenzhen Bay by GDS consolidation test system. Regression fitting analyses on three kinds of nonlinear relationships of void ratio-effective stress for soft soil were performed, and some fitting parameters were also obtained. The obtained results show that：After a certain consolidation pressure between 6 kPa and 400 kPa, with the decrease of void ratio, a nonlinear variation in compression coefficient, volume compression coefficient and compression modulus of dredged fill is shown, which varies several tens of times of magnitude. A nonlinear decrease in compression index of dredged fill is also shown, which decreases one twice with the decrease of the void ratio. Compression strain of dredged fill is as high as 24.44% under the first stage of small consolidation pressure, which is half of that compression strain at the entire consolidation pressure.Three kinds of nonlinear function relationships of void ratio-effective stress for soft soil are conformable with dredged fill in Shenzhen Bay. Because of the characteristics by a simple form, good applicability and best fitting,the power function relationship of void ratio-effective stress can be used in the study on compression characteristics and the numerical analysis on nonlinear and finite-strain consolidation behaviors of ultra-soft soil such as dredged fill.