Abstract: It is troublesome to collect and prepare specimens of silty soil in practice, posing difficulties to obtaining parameters. In this paper we discuss the feasibility and pivotal problems of multilevel tri-axial test on silty soil. We summarize that the number of loading steps is 3 and the disparity among steps should be controlled within 30kPa. The time of consolidation are 10 minutes and 20 minutes respectively. As for failure criterion, the first stage failure is determined to be when axial strain reaches 12% or when axial pressure gets stable; the second and third stage failure are both determined when axial pressure gets stable. The tests in this paper prove that multilevel triaxial test could overcome the difficulties of collecting and preparing silty soil specimens, and the obtained parameters are reasonable with slight deviationsthe cohesion is slightly larger and internal friction angle is slightly smaller. These parameters could be adopted after correction, and the multilevel triaxial test is proved to be an economical and feasible method.

Key words: silty soil, strength recycled, multilevel triaxial test, number and disparity of loading steps, time of consolidation, failure criterion, shear strength