(1. School of Civil Engineering and Mechanics，Lanzhou University，Lanzhou，Gansu 730000，China；2. Key Laboratory of Mechanics on Disaster and Environment in Western China，Ministry of Education，Lanzhou University，Lanzhou，Gansu 730000，China)
Abstract：This paper studies the improvement mechanism of loess soil modified by the consolid system in comparison with the loess soil modified by cement and lime. The mechanical strength test，disintegration test and flexible-wall permeability test were conducted to measure the engineering property of soil. The water drop penetration time test，X-Ray diffraction test，scanning electron microscope(SEM) test and mercury intrusion porosimetry(MIP) test were carried out to investigate the microscopic properties，such as the surface energy，mineral composition，microstructure and pore filling condition of loess soil. The loess soil modified by the consolid system has higher strength，better durability of slaking and slightly lower permeability. The surface energy of soil particles is reduced greatly and the water repellency ability is obviously better than that of cement or lime modified loess soil. The phase peak groups are basically same in the X-ray diffraction patterns. The silt particle arrangement of loess soil remains unchanged with the increase of consolid system content，but the fine particles coagulate with more adhering material. The volume of large，medium and small pores in loess soil are reduced slightly while the micro pores are increased obviously. The improvement mechanism of loess soil modified by consolid system is that the decrease of surface energy of loess soil enhances the water repellency and water-resisting property，the consolid system reinforces the bonding strength of the microstructure of soil particle skeleton，the weak swelling and pore filling effect of consolid system lead to good permeability of loess soil. Apart from improving the mechanical and hydraulic properties，the consolid system solve the problem of improving the water resistance property and keeping the good permeability of loess soil to some extent.
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2017, Vol. 36 
