阳离子半径对电化学法加固软黏土效果的影响试验研究

Experimental study on the influence of cationic radius on the effect of reinforcement of soft clay by electro-chemical treatment

在电化学法加固中,注浆试剂种类一直是主要研究课题之一。化学试剂的注入对土体电动特性存在一定影响,主要影响因素为注浆溶液的阳离子种类、离子浓度、离子价位、离子半径等,土体的电动特性改变对电渗加固效果的影响不可忽视。因此,为研究注浆试剂中的阳离子半径对电化学法加固软土地基效果的影响,以同价位不同半径的二价金属离子Ca^(2+)、Mg^(2+)、Cu^(2+)为研究对象,进行电渗固结试验研究。对试验过程中的电流、排水量、电渗透系数变化及试验后的含水率与抗剪强度分布进行分析,并结合扫描电镜(SEM),深入探究阳离子半径对电化学加固效果的影响。结果表明:在电化学法中,提高注入试剂中阳离子的离子半径,电渗过程中的电流、排水量、排水速率、电渗透系数及处理后的土体抗剪强度均有明显提升,其中,钙离子的离子半径最大,加固效果最好,试验后的土体SEM微观图像也表明,钙离子处理后土体密实度更高。

In the electro-chemical reinforcement method,the type of injecting solutions has been one of the main research issues.The injection of chemical solution has a significant impact on the electrokinetic properties of the soil,and the main influential factors include the types of cation,ion concentration,cation valence,cation radius,etc.of the injecting solutions.The change of the electrokinetic properties of the soil has a non-negligible impact on the electro-osmotic reinforcement effect.In order to study the effect of cation radius in injecting chemical solutions on the effect of electro-chemical reinforcement of soft soil foundation,taking the divalent metal ions Ca^(2+),Mg^(2+),Cu^(2+)with different radii of the same valence as research objects,the changes of current,drainage volume,electric permeability coefficient during the test and the distribution of water content and shear strength after test were analyzed,combined with scanning electron microscope(SEM)to explore the effect of different radii of cations on the electro-chemical reinforcement effect.The results show that increasing the ionic radius can significantly improve the current,drainage rate,electric permeability coefficient and shear strength of the soil after treatment.Among them,the cation radius of Ca^(2+)is the greatest,and the reinforcement effect of calcium ions is the best.The SEM images also show that soil compactness is higher after calcium ion treatment.