Stress relaxation is a major time-dependent behavior of unsaturated lime-treated expansive clay. In this paper,effects of loading mode,strain level and strain rate of primary loading on the subsequent stress relaxation were investigated by means of geotechnical digital system( GDS) for unsaturated soils. The results showed that the incomplete relaxation occurred in the specimens. Patterns of measured curves were similar and of periodic fluctuations. For relaxation tests performed with the initial loading at...