台州地区吹填土的工程特性及土性指标分析

Analysis of engineering properties and soil indexes of dredger fill in Taizhou region

作为地基处理设计的基本参数,吹填土的土性指标具有很强的地域特征和不确定性。为了更好地研究吹填土的工程特性,取台州东部新区经过一次真空预压处理后的吹填土作为研究对象,对其进行现场和室内土工试验,得到预压处理后吹填土的基本物理力学性质指标和固结变形特性,以及土性指标间的相关性。研究结果表明:台州地区吹填土主要由淤泥质粉质黏土组成,含有少量贝壳碎屑和腐殖质;经一次预压处理后的吹填土含水量高、孔隙比大、渗透系数小、压缩变形大,其工程性质仍然很差;预压处理后吹填土的天然含水量、天然孔隙比、液限和塑性指数间有很好的线性相关性,液限和塑限间的线性相关性不明显;吹填土试样的固结压应力—应变等时曲线和蠕变曲线表现出明显的非线性特性,其应变速率—时间双对数曲线具有较好的线性相关性。研究成果可为沿海地区吹填土地基处理和工程建设提供参考。

As the basic design parameters of foundation treatment,the soil indexes of dredger fill have strong regional characteristics and uncertainties.In order to better investigate its engineering characteristics,the dredger fill treated by primary vacuum preloading in the eastern new area of Taizhou city is taken as the research object.The basic physical and mechanical properties,the consolidation deformation characteristics,and the correlation of physical and mechanical parameters of the dredger fill after primary preloading treatment are obtained through indoor and field tests.The results show that the dredger fill in Taizhou region is mainly composed of silty clay with a small amount of shell debris and humus.The engineering properties are still poor due to its high water content,large void ratio,small permeability coefficient,and large compression deformation.After primary preloading treatment,there is a good linear correlation among the natural water content,natural void ratio,liquid limit,and plastic index of dredger fill.But the linear correlation between the liquid limit and the plastic limit is not obvious.The compressive stress-strain isochronal curves of consolidation and the graded loading creep curves through lateral compression test exhibit show a non-linear correlation.The strain rate-time logarithmic curves have a good linear correlation.The research results can provide a reference for foundation treatment and engineering construction of dredger fill in the coastal region.