关键词: 草炭土, 纤维含量, 直剪特性, 快剪试验, 固结快剪试验, SEM图像

Abstract: Hemic turfy soil and sapric turfy soil were selected from Jiangyuan Town, Dunhua City, Jilin Province as samples to analyze their direct shear characteristics and mechanical mechanism in seasonal frozen region by indoor fast shear and consolidated-fast shear experiments. The test results demonstrated that the relation curve between normal stress and peak of the shear stress was linear that conforming to Mohr-Coulomb criterion. The relation curve was a two-section line with a turning point at normal stress 200 kPa. Based on the Mohr-Coulomb criterion, the piecewise function was established, and the improved formula in accordance with the change rule of turfy soil was obtained. The obtained direct shear characteristics and strength parameters can be used as reference for the parameters valuing of subgrade stability evaluation in seasonal frozen region.

Key words: turfy soil, fiber content, direct shear characteristics, quick direct shear test, consolidated-quick shear test, SEM image