城市环境下粘性土的强度磁效应

Strength Magnetic Effect of Cohesive Soil Under City Environment

通过室内试验研究,揭示了城市附加磁场对粘性土强度的影响.经磁化处理后,南宁市邕江Ⅰ、Ⅱ级阶地冲积相粘性土的强度有所增大.原状土在100 kPa围压下峰值强度基本上不变,200～400 kPa围压下峰值强度增幅可达3.9%～17.0%.重塑土的峰值强度增幅可达10%～18%.城市附加磁场可对粘性土的土粒表面电荷及双电层结构产生影响,并使孔隙水中化学组分发生磁化学反应,导致粘性土土粒间的细观连接强度产生变化,从而使粘性土的强度发生变化.

Form laboratory experiments, the influence of superimposed magnetic field on strength of cohesive soil is found. After magnetization handles, the strength of river alluvial cohesive soil of first and second terrace of Yong River of Nanning City are strengthened. The peak strength of undisturbed sample keeps stability under 100 kPa confining pressure, but its increment range can reach 3.9% - 17. 0% under 200 -300 kPa confining pressure. The peak strength increment range of remolded sample can reach 10% - 18%. Superimposed magnetic field on city produces an effect on electric double layer and charges on the surface of cohesive soil particle, with a magnetic-chemical reaction of chemical components in void water and a change of connected strength among cohesive soil particle. Finally it leads to the strength change of cohesive soil.