Abstract:

Soft rock with expansion properties is distributed widely along the highway in Yanbian area which gave rise to instability of slopes and brought about great damage in this area. In order to describe the strength and stress-strain characteristics of the geotechnical dielectric material in this area, the stability of Xinyan landslide on the Wangqing-Yanji highway in Jilin Province was analyzed and parameters of the support work were provided. Indoor consolidation-undrained shear test was carried out on the soil samples taken from the construct site. Results revealed that the stress-strain curves of the samples were typical hyperbola under low confining pressure, the soil exhibited weak strain hardening; while under high confining pressure, the soil displayed obvious strain hardening behavior. In association with Duncan-Chang model, the test results were analyzed to obtain parameters of the model. On the basis of this, the normalized behavior of expansive soil in this area was studied, and the results showed that the normalized degree was highest when the normalization factor was (σ₁-σ₃)_ult. Furthermore, the normalized equation of strain-stress curves was established, which would well predict the variation trend of stress-strain relation.

Key words: swelling soft rock, consolidation-undrained shear test, Duncan-Chang model, normalized behavior