高原湖相泥炭土渗透特性研究及机制分析

为明确高原湖相泥炭土渗透特性并建立渗透模型，采用固结-渗透联合试验装置对取自6个场地20余组土样天然状态及一维压缩过程中渗透系数进行测定，并分析了加载时长、应力水平以及烧失量、残余纤维含量等因素对其渗透性的影响。试验结果表明：分别加载条件下，泥炭土渗透系数 随加载时长T增大而减小并趋于稳定，稳定时长在10 d左右；分级加载条件下， 随固结应力 的增大呈非线性减小， - 关系曲线为反S型；高原湖相泥炭土渗透模型可用e- 表示，其渗透指数 与初始孔隙比 满足关系式 0.25 ；初始渗透系数 和烧失量 、残余纤维含量 及 关系较为离散， 和 、 及初始含水率 有一定的正相关性。通过电镜扫描试验，从土中孔隙特征角度探讨了高原湖相泥炭土渗透特性的机制。

Hydraulic conductivity of lacustrine peaty soil in plateau areas and its mechanism analysis

To explore the hydraulic conductivity of lacustrine peaty soil in plateau areas, the permeability coefficients of 20 groups of soil samples from 6 sites were measured under one-dimensional compression conditions through oedometer tests. The effects of loading time, stress level, loss-on-ignition and residual fiber contents on the permeability coefficients are analyzed. The experimental results show that under the conditions of separately loading, permeability coefficient decreases with the elapsing time and tends to be stabilized in about ten days; under the conditions of stepwise loading, the permeability coefficient decreases nonlinearly with increasing consolidation pressure, and the curves of - resemble a reverse “S”. A permeability model for lacustrine peaty soil in plateau areas can be represented by expression e- , and the relations between the permeability index ( ) and initial void ratio can be described by 0.25 . The relationships among initial permeability coefficient and loss-on-ignition , residual fiber content and are more discrete, and there clearly exits a positive correlation among , , and the initial water content . Through scanning electron microscope, the mechanism of the peaty soil permeability is discussed from the pore characteristics of soil.