Chemical consolidation is one of the most effective methods for solving the engineering problems of saline soil

such as salt expansion

collapse and erosion. Based on the unconfined compressive strength test

X-ray diffraction

chemical analysis and scanning electronmicroscope

the solidification mechanism and strength characteristics of the sulphate saline soil solidified by lime

fly ash and sodium silicate are analyzed. The results show that when the lime content is less than 8%

the compressive strength and shear strength of lime-reinforced soil

fly ash and sodium silicate are higher than those of the sulphate saline soil solidified by lime and fly ash; the strengths of the former grow almost linearly with the concentration of sodium silicate. The alkali-activated action on fly ash caused by sodium silicate and adsorption between sodium silicate and saline soil generate mass gels

leading to an increase in contact area between framework grains

a reduction in intergranular pore

and a transformation from point-contact to surface-contact. The grains of saline soil bond each other into 3D framework via gels

resulting in an increase in the strength of saline soil. Meanwhile

the salt expansion behavior of saline soil is also restrained effectively due to the sharp reduction in the content of induced by complex physicochemical reactions as saline soil is solidified.