Dispersive clay is a type of water sensitive soils

which has the characteristics of dispersing and material losing when encountering water. The influence factors and modification mechanism of dispersive clay modified by calcium lignosulfonate were studied using dispersity tests

mechanical property tests

chemical property tests

microstructure tests and simulated rainfall scouring tests. The results indicated that with the increase of calcium lignosulfonate content

the dispersity

disintegration and erosion resistance of the modified soil were gradually improved

and it had a good modification effect when the content reached 3.0%; the unconfined compressive strength first increased and then decreased

and the compression coefficient first decreased and then increased

and both achieved extreme values at 0.5% content. With the increase of curing age

the dispersity and disintegration of the modified soil decreased gradually

the compression coefficient decreased significantly

and the compressive strength increased gradually. At the age of 28 days

the unconfined compressive strengths of the modified soil at 0.5% and 3.0% contents were increased by 50% and 20% respectively

compared with that of dispersive clay. The engineering properties of dispersive clay were improved by the addition of calcium lignosulfonate mainly through reduction of thickness for electric double layer

cation bridging

particle cementation and hydrophobic effect of hydrophobic group. However

when the content of calcium lignosulfonate was too large

the calcium lignosulfonate would preferentially combine with itself and weaken the attraction between soil particles

which would increase the porosity and decrease the mechanical properties of soil. The research concludes that calcium lignosulfonate has a good modifying effect on the dispersive clay

which can significantly improve the water sensitivity

water stability and erosion resistance of clay.