基于GDS固结渗透试验吹填土固结系数研究

基于一维大变形固结方程,给出了不同描述方法时大变形固结系数的表达式,采用软黏土渗透系数及有效应力与孔隙比间的半对数线性关系和幂函数关系,探讨了大变形固结系数随孔隙比的变化规律,提出了大变形固结系数随孔隙比变化的条件关系式,并应用于GDS固结渗透试验吹填淤泥固结系数变化特征分析.研究结果表明:1)存在临界孔隙比,将3种定义的大变形固结系数分成不同变化特征的单调区间,利用条件关系式能较好地判断大变形固结系数的变化规律.2)深圳前湾吹填淤泥大变形固结系数随孔隙比的减小变化幅度达1~2个数量级,比小变形固结系数的变化幅度更大,在对吹填淤泥等超软土进行大变形固结计算时,应先明确大变形固结系数的变化规律.

Study on Coefficient of Consolidation of Dredged Fill Based on GDS Consolidation and Permeability Test

Based on one dimensional large-strain consolidation equations,the expressions of large-strain coefficient of consolidation in different coordinates and variables are given in this paper.In order to study the variation regularity of large-strain coefficient of consolidation with void ratio,it is introduced that the coefficient of permeability-void ratio and effective stress-void ratio follow the semilogarithm linear and power function relation for soft clay soil.The condition relationship formulae of variation of large-strain coefficient of consolidation with void ratio is proposed,which is applied to the analysis on coefficient of consolidation of dredged fill in GDS consolidation and permeability tests.The obtained results verifies that: 1) Three kinds of large-strain coefficient of consolidation are divided into different monotony intervals by the critical void ratio.The condition relationship formulae can be applied preferably in determining the variation regularity of large-strain coefficient of consolidation.2) the large-strain coefficient of consolidation of dredged fill varied 1-2 orders of magnitude with the decrease of the void ratio in Shenzhen Qianwan area,of which the variation is more larger than small-strain coefficient of consolidation.The variation regularity of large-strain coefficient of consolidation should be understood before large-strain consolidation calculation of dredged fill is conducted.