原状欠固结土的力学特性试验研究

原状土的结构性对它的力学性质影响显著。通过多应力路径的原状土与重塑土的试验结果比较来揭示原状土体从小应变到大应变的特殊力学特性及应力路径的影响。从等压固结对比试验可看出该原状样明显的结构性与欠固结性。对于原状欠固结土,体应变对土体结构性的破坏要大于剪应变。原状欠固结土的结构性对土体强度的影响主要表现在内摩擦角的增大。土体小应变时表现出明显的高刚度与非线性。通过不同方向切样的原状土试验结果对比,反映了原状土体存在明显的各向异性,结构性引起的各向异性在应变越小时越明显。

TESTING STUDY ON MECHANICAL CHARACTERISTICS OF NATURAL UNDERCONSOLIDATED SOILS

The mechanical characteristics of natural soils are significantly affected by their structure.The special mechanical characteristics of natural soils and the influence of stress path on natural soils are disclosed through the comparison of results of tests on natural soils and manipulated soils with multiple stress paths.The structural and underconsolidation behaviors of natural soils are shown in the normal consolidation experiment.The structure damage of the natural underconsolidated soils caused by the increment of volumetric strain is more significant than that caused by the increment of shearing strain.The influence of the structure on natural soils is mainly embodied as the increase of internal friction angle.At small strain,natural soils are of high stiffness,obvious nonlinearity and are markedly different from the manipulated soils.Through the comparison of test results of natural soil samples cut from different direction,the anisotropy of natural soils which becomes obvious as strain decreases is illustrated.