天然沉积软黏土渗透系数随应力水平的变化规律

以天然沉积温州软黏土为研究对象,进行了一系列的固结渗透试验,探讨天然沉积土压缩过程中渗透系数的变化规律。研究结果表明:天然沉积土由于沉积过程中受到土结构性的影响,存在明显的固结屈服压力,当固结压力小于屈服压力时压缩性小,渗透系数变化不明显;当固结压力大于屈服压力后压缩性激剧增大,渗透系数呈现明显的变小趋势,渗透系数与固结压力的关系与压缩曲线一样存在明显的拐点。基于ln(1+e)与lgσv’以及ln(1+e)与lg kv所呈的双对数坐标系下的线性化分析,提出了压缩过程中渗透系数随应力水平变化的相关关系式。

Change in Hydraulic Conductivity of Natural Clays during Compression

A series of falling head hydraulic conductivity tests were performed on natural Wenzhou clays consolidated at different stress levels using modified oedometric apparatus to investigate the change law of hydraulic conductivity of natural clays during compression. It is found that both the compression behavior and the hydraulic conductivity behavior are significantly affected by the yield stress caused by the soil structure formed during the depositional and post-depositional processes. When the consolidation pressure is less than yield stress, the compressibility is small and the variation of hydraulic conductivity is not obvious; when the consolidation pressure is larger than yield stress, the compressibility increases dramatically and the hydraulic conductivity varies clearly with the stress level. The change in hydraulic conductivity with the increase in stress level is discussed, and a method of predicting hydraulic conductivity during compression is proposed.