Abstract:

In order to enlarge the usage extent of roadbed fillings of high-speed railway, the stress-strain relationship and failure shapes were studied on the cement- and lime-modified soil under different freeze-thaw cycles, cooling temperature and confining pressure. The results showed that stress-strain relationship of cement soil was work-softening. The stress-strain relationship of lime soil turned into work-hardening subjected to freeze-thaw cycles. Cement soil was mainly in a brittle failure state, and lime soil was in a ductile failure state. The effects of confining pressure on stress-strain curves of modified soils were not distinct, and the peak strength of modified soils increased with the confining pressure increasing. The cohesion decreased with increasing of the number of freeze-thaw cycles, but there was no changing law for the internal friction angle. The effect of cooling temperature on the cohesion was not obvious. The improvement effect of cement was superior to lime under repeated freezing and thawing.

Key words: cement soil, lime soil, static properties, freeze-thaw cycles