大变形自重固结理论可广泛应用于堆场设计和堆场吹填淤泥处理等方面,但对于沉积柱试验中淤泥的自重固结性质,尤其是非线性压缩关系和非线性渗透关系,并没有进行详细深入地研究。利用研制的沉积固结试验方法研究了太湖和白马湖吹填淤泥的自重固结性质。该方法由沉积柱、孔隙水压力测试装置和分层真空取样装置组成,利用该方法可得到淤泥自重固结过程中泥水界面、超静孔隙水压力、密度、有效应力、颗粒分布、压缩关系和渗透关系等参数的变化规律。压缩关系试验结果表明:两种淤泥压缩关系是非线性的。在较低的有效应力时随有效应力的增大孔隙比迅速减小,在较高的有效应力时随有效应力的增大孔隙比减小趋势趋缓。存在一个有效应力的分界点,低于此点不同时间时有效应力与孔隙比的关系较为分散,此时淤泥的压缩性很大,高于此点不同时间时有效应力与孔隙比的关系可认为是唯一的。两种淤泥渗透关系是非线性的。淤泥的非线性压缩关系和渗透关系可采用幂函数关系。
The large-strain self-weight consolidation theory is widely used for the design of dredged material disposal sites and the treatment of hydraulically dredged slurries in the disposal sites. The self-weight consolidation behavior of hydraulically dredged slurries in settling column experiments, especially nonlinear compressibility relationship and nonlinear permeability relationship, is still unclear. The self-weight consolidation behavior of hydraulically dredged slurries from Taihu Lake and Baimahu Lake is studied by using a new sedimentation and consolidation experimental method which consists of a settling column, a pore pressure measurement apparatus and a multi-layer vacuum extraction sampling apparatus. It can test the changing rules of the interface height, excess pore pressure, density, effective stress, grain size distribution, compressibility relationship and permeability relationship in self-weight consolidation. The experimental results show that the compressibility relationship is nonlinear. Under low effective stresses, the void ratio changes significantly with a small increase in the effective stress, while under higher values of effective stress, change of void ratio with effective stress is more limited. When values of effective stress are greater than one value, a unique relationship is visible, and when the stresses are below this value, the data points cover a triangular shaped area, so the compressibility is large. The permeability relationship is nonlinear. The compressibility relationship and permeability relationship can be represented by a power function equation.