CAJ | 학술논문

天然沉积土在沉积过程中产生了结构性和各向异性，使其受力变形特性与重塑土存在明显的差异。实际工程中的天然土体往往在受荷过程中会经历不同的应力路径，因此，需要开展考虑结构性和各向异性影响的应力路径试验。通过研究不同应力路径下土体的力学特性，为建立复杂应力路径下的合理的本构模型提供试验依据。采用大直径PVC 管取样器获取张家港地区地下2.5 m深的粉质黏土不扰动土样，通过GDS三轴仪对土样进行了K0固结不同排水应力路径试验。结果表明，应力路径对不扰动土样的体积变形和剪切变形均有显著影响，且球应力和偏应力对土的体应变和剪应变存在交叉影响。无论以体积变形为主还是剪切变形为主的应力路径下，应力-应变曲线都有明显的屈服性状。通过描绘试验所得各应力路径下的屈服点，获得张家港不扰动土样的屈服轨迹大致呈倾斜的椭圆形状，采用Wheeler模型的屈服面与试验屈服点的吻合程度要优于Nakano模型。
천연침적토재침적과정중산생료결구성화각향이성，사기수력변형특성여중소토존재명현적차이。실제공정중적천연토체왕왕재수하과정중회경력불동적응력로경，인차，수요개전고필결구성화각향이성영향적응력로경시험。통과연구불동응력로경하토체적역학특성，위건립복잡응력로경하적합리적본구모형제공시험의거。채용대직경PVC 관취양기획취장가항지구지하2.5 m심적분질점토불우동토양，통과GDS삼축의대토양진행료K0고결불동배수응력로경시험。결과표명，응력로경대불우동토양적체적변형화전절변형균유현저영향，차구응력화편응력대토적체응변화전응변존재교차영향。무론이체적변형위주환시전절변형위주적응력로경하，응력-응변곡선도유명현적굴복성상。통과묘회시험소득각응력로경하적굴복점，획득장가항불우동토양적굴복궤적대치정경사적타원형상，채용Wheeler모형적굴복면여시험굴복점적문합정도요우우Nakano모형。
Soil structure and anisotropy were generated during the depositional process for natural sedimentary soils, which made them different form that of the remolded soils. Since natural soils may generally undergo different stress paths during external loads in the engineering practice;it is necessary to carry out stress path tests on natural soils both considering the effects of soil structure and anisotropy. Analysis of mechanical behavior under different stress path tests can be the basis for set up reasonable constitutive model for natural soils. In this study, different K0 consolidation drained stress path triaxial tests were performed by GDS triaxial apparatus on undisturbed Zhangjiagang silty clays, which were taken by large diameter PVC samplers from depths of 2.5m underground. Test results show that stress paths exert significant influence on volumetric and shear deformation. Global stress and deviator stress have cross effects on the volumetric strain and shear strain. Obvious yielding behavior can be observed in stress-strain relations, whatever the stress paths are controlled by volume or shear deformation. Yielding curve obtained by connecting the yield points under different stress paths shows an incline elliptical shape, which agrees better with the yield curve in the constitutive model proposed by Wheeler et al. than that of the model presented by Nakano et al..