从流动到可塑状态软黏土的一维固结特性试验研究

软土在固结过程中含水率的减小将导致其物理状态从流动态进入可塑态,为研究物理状态变化对软黏土的压缩性和渗透性的作用影响,采用饱和重塑黏土,配制高于液限含水率和接近液限含水率的试样,分别开展不同压力作用下的一维固结试验,依据位移和孔压测试数据,对比分析了固结过程中的位移发展、孔压消散、压缩系数以及渗透系数的变化特性。结果表明:在流动状态下,位移快速发展,而孔压却存在明显的滞消现象;进入可塑状态后,压缩系数和渗透系数的对数随孔隙比的变化关系均发生明显的转折。这意味着,在软土固结问题的理论分析中,应考虑物理状态的变化对土体压缩性和渗透性参数变化规律的影响。

Experimental study on one-dimensional consolidation behavior of soft clay from liquid state to plastic state

Decrease in the water content of soft soil under consolidation will lead to a change from liquid state to plastic state. An experimental study is conducted to investigate the effects of change in the physical state on the compressibility and permeability of soft clay. The saturated and reconstituted clay specimens are prepared with water contents higher than and close to the liquid limit. One-dimensional consolidation tests are carried out under different vertical pressures. Based on the test results, a comparative analysis is conducted on the deformation, dissipation of pore-water pressure, and changes in the coefficient of compressibility and the hydraulic conductivity during the consolidation process. It is shown that in the liquid state, the deformation increases quickly, but the stagnation phenomenon of pore-water pressure dissipation appears clearly. There is an evident change in the relations between the logarithms of the coefficient of compressibility and the hydraulic conductivity and the void ratio when the soil state is transited to the plastic one. It is implied that the effects of the transition of physical state on the changes in the compressibility and permeability parameters should be taken into account in the theoretical analysis of consolidation problems of soft soil.