吹填泥浆中土颗粒沉降-固结规律研究

Study of sedimentation and consolidation of soil particles in dredged slurry

吹填泥浆中土颗粒沉降-固结过程十分复杂,其中土颗粒的沉降固结规律并不明确。室内沉降试验采用一种改进的方法——分层抽取法,先得到土颗粒体积分布规律,再利用体积通量函数法计算不同粒组颗粒平均沉速。计算结果表明,吹填泥浆在沉降过程中会出现3个区域,分别是干涉沉降区、絮体压缩沉降区和自重固结区;在沉降初期0～1 h和1～7 h内,干涉沉降区内土颗粒沉速远小于Stokes公式沉速计算值,颗粒沉速分别与颗粒直径的0.488 1和0.111 7次方有关。絮体压缩沉降区和自重固结区内颗粒基本不出现分选现象,均属于泥浆颗粒的沉积物;该试验中絮体压缩沉降区的密度约为1.04 g/cm3。

The process of sedimentation and consolidation of soil particles in dredged slurry is very complex, and it is not clear about the sedimentation and consolidation of soil particles. A modified experiment method which is called multilayer extraction sampling is adopted in laboratory test. The volume distribution regularity of soil particle is firstly obtained, and then the average settlement velocities of soil particles in different soil fractions by using volume flux function method are calculated. The result reveals that： there are three different zones existing during the sedimentation and consolidation of soil particles in dredged slurry. They are hindered settlement zone, floc compression settlement zone and self-consolidation zone separately. During the first hour and the next 6 hours, the velocity of soil particles is much smaller than the velocity calculated by using Stokes equation in hindered settlement zone, and it is related to the particles diameter of 0.488 1 and 0.111 7 th power. There is no separation of soil particles in floe compression settlement zone and self-consolidation zone. All soil particles in these two zones are belong to the sediments. The density of floc compression settlement zone is about 1.04 g/cm^3.