离子型土壤固化剂改性淤泥排水固结试验研究

Experimental Study on Drainage and Consolidation Properties of Muck Modified by Ionic Soil Stabilizer

通过自主研制的真空预压与堆载预压模拟试验装置,对原状淤泥土样品与不同浓度离子型土壤固化剂(ISS)改性淤泥土样品开展了排水固结模拟试验,结合改性前后淤泥土样品的阳离子交换量、塑性指数和渗透系数变化数据,探讨了ISS改性淤泥加速排水固结过程的机理。试验结果表明:与原状淤泥土样品相比,经ISS改性后淤泥土样品的排水固结速度加快64.7%,最终固结沉降量增大13.4%,阳离子交换量降低66%,塑性指数下降38%,渗透系数提高2个数量级;ISS改性淤泥加速排水固结过程的机理包括两个方面,一是ISS的作用使土颗粒表面结合水量降低,黏滞性水膜减薄,转换为更容易排出土体的毛细水及自由水;二是土颗粒表面结合水膜减薄使大部分封闭的无效孔隙开放连通,成为有效的渗流通道,显著提高了土体的渗透性。

Drainage and consolidation properties of muck with and without modification by ionic soil stabilizer(ISS) are tested by self-developed vacuum and surcharge preloading simulating devices.The mechanism of accelerating drainage and consolidation process by modified muck is discussed in combination with the change data of the cation exchange capacity, plasticity index and permeability coefficient of samples before and after modification.The test results indicate that after modification, the drainage and consolidation speed of mud samples increases by 64.7%,the final consolidation settlement increases by 13.4%,the cation exchange capacity decreases by 66%,the plasticity index decreases by 38%,and the permeability coefficient increases by 2 orders of magnitude.The mechanisim of ISS-modified muck accelerating drainage and consolidation process includes two aspects.Firstly, ISS reduces the bound water on the surface of soil particles, reduces the viscous water film, and converts it into capillary and free water easier to drain from soil.Secondly, the thinning of the bound water film on the surface of soil particles makes the closed void pores open and connected, which becomes effective seepage channels and significantly improves the permeability of soil.