FS型固化剂固化沙漠风积砂土的孔隙特征试验研究

Experimental study on pore characteristics of desert aeolian sandy soil cured with fly ash-based composite stabilizing agent(FS)

本文采用FS型固化剂固化库布其沙漠风积砂土,用扫描电镜(SEM)、核磁共振(NMR)试验对固化土孔隙结构进行分析,从微观结构角度入手解读固化土从受力到破坏的整个过程.结果表明:FS型固化剂固化土内部存在粒间孔、微裂纹以及凝胶体内部孔,在加载过程中,固化土中的粒间孔首先被压缩,类似土体,然后凝胶体受荷损伤破坏,粒间孔增加;继续加荷粒间孔再被压缩,如此直到出现连通的裂隙面.固化土的孔喉分布集中分布在0-0.1μm.这与风积砂土的级配有关,0-0.1μm孔喉分布占10%左右,基本控制了固化土渗流特性.

In this paper,the aeolian sandy soil in Khovch Desert was cured by the composite stabilizing agent FS,and the microstructure of the solidified soil was analyzed by SEM and NMR to see how it behaves under loading in the process from loading to damage.The results show that there are intergranular pores,microcracks and internal pores in the solidified soil with the FS type curing agent.During the process of loading,intergranular holes are compressed first,like soil,then the gels are damaged and the intergranular pores increase.As loading continues to increase,the intergranular pores are compressed,until there appears a connected crack surface.The pore throat distribution of stabilized sand soil is concentrated at 0-0.1μm,which is related to the grading of the aeolian sand soil.When the distribution of the pore throat of 0-0.1μm is about 10%,the seepage characteristics of the solidified soil are basically under control.