离子土固化剂固化淤泥的微观机理研究

MICROSCOPIC MECHANISM OF SOLIDIFIED SILT WITH IONIC SOIL STABILIZER

采用离子土固化剂对武汉典型淤泥进行化学加固,通过阿太堡界限试验获得不同配合比加固土的塑性指数;对离子土固化淤泥前后的样品开展了压缩性能、微观结构、比表面积、化学成分、能谱分析和阳离子交换等试验,研究离子土固化剂对淤泥加固的宏观表现与微观作用机理。试验结果表明:经离子土固化剂处理后的淤泥压缩性减小,孔隙变小,离子土固化剂促使土颗粒之间聚集、凝结,团聚体明显增大,比表面积减小,比表面能降低,土体结构更致密。淤泥固化前后其化学成分并没有发生改变,离子土固化剂与淤泥胶体颗粒表面的反离子层发生了阳离子交换反应,固化剂稀释液中部分K+、Na+离子被淤泥土截获吸附,黏土颗粒表面的Ca2+、Mg2+离子被解析出,使扩散层厚度变薄,ξ电势降低,黏土胶体颗粒聚结,提高了土颗粒之间的联结强度和稳定性,从而达到土壤改性加固的目的。

The typical silt in Wuhan is solidified with Ionic Soil Stabilizer(ISS).The plasticity index of soil with different mix proportions is obtained through the test of Atterberg limits.The compressive properties,microstructure,specific surface area,chemical composition,energy spectrum analysis and cation exchange test are carried out before and after the solidification of silt with ISS.The macroscopic and microscopic mechanism of the solidification of silt with ISS are studied.The test results show that the compressive strength of silt treated with ISS decreases and porosity decreases.Ionic Soil Stabilizer promotes aggregation and condensation of soil particles,aggregates obviously increase,specific surface area decreases,specific surface energy decreases,and soil structure is denser.There is no change in the chemical composition of the silt before and after solidification.Cation exchange reaction occurs between the ISS and the counter ion layer on the surface of the silt colloid particles.The K+and Na+ions in the diluents of the curing agent are captured and adsorbed by the silt.The Ca 2+and Mg 2+ions on the surface of clay particles are resolved,which makes the thickness of the diffusion layer thinner,theξpotential decreased,and the clay colloid particles coalesced.ISS improves the strength and stability of the soil particles,so as to achieve the purpose of soil modification and solidification.