两种吹填超软土压缩固结特性试验研究

Experimental Study on the Consolidation Characteristics of Two Dredged Ultra-Soft Soils

吹填超软土含水量高、压缩性高、低强度、低渗透性等特点,压缩固结过程不同于一般的软土,表现出非线性变化的特点。对上海两种吹填超软土采用压缩固结试验,通过试验研究其压缩、固结特性,试验结果表明:①两种吹填超软土第一级荷载压缩量最大,压缩系数最大,而且随着固结压力增大压缩系数逐渐减小,同时孔隙比与荷载的对数近似呈线性关系。②两种吹填超软土其固结系数随着所加荷载的增加而增大,而其渗透系数随着所加荷载的增加而减小。③渗透系数随孔隙比呈非线性变化,采用非线性函数拟合lgK_v-e关系,为类似吹填超软土非线性固结提供参考。

The dredged soil has the engineering properties of high moisture content, high compressibility, low shear strength and low permeability. With a nonlinear characteristic, the consolidation process of the dredged soil is different from the conventional soft soils. This paper presents the results of consolidation tests on two types of dredged ultra-soft samples. The following conclusions can be obtained: 1) Under the first loading increment, the highest compression(highest compression coefficient) was observed in both types of samples. Lower compression coefficient was found in higher consolidation load. A linear relationship between the void ration and the logarithmic consolidation pressure. 2) The coefficient of consolidation in both types of soil samples increased and the coefficient of permeability decreased with the increase of the consolidation pressure. 3) non-linear relationship can be found between the logarithmic coefficient of permeability and the void ratio and this relationship(log kv-e) could be established by using a nonlinear curve fitting.