AN ELASTO-PLASTIC MODEL FOR UNSATURATED SOIL IN THREE-DIMENSIONAL STRESSES
AN ELASTO-PLASTIC MODEL FOR UNSATURATED SOIL IN THREE-DIMENSIONAL STRESSES
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DOI：
10.3208/sandf.40.3_17
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发表时间：
2000-06
影响因子：
3.7
通讯作者：
De’an Sun;H. Matsuoka;Yang-ping Yao;W. Ichihara
中科院分区：
文献类型：
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作者：
De’an Sun;H. Matsuoka;Yang-ping Yao;W. Ichihara
摘要采用基于扩展SMP准则的应力张量变换，建立了非饱和土的三维弹塑性模型。该模型考虑了吸力对非饱和土力学性质的影响，采用了一个名为吸力σ0(S)的参数，将其与净应力相加形成有效应力，并将屈服应力与模型参数联系起来。该模型所需材料参数较少，可通过固结仪、直剪试验或三轴试验等常规试验结果确定。它可以预测在三维应力和恒定吸力或变吸力条件下非饱和土应力-应变-强度特性。利用吸力控制三轴仪对非饱和压实高岭土进行了大量的三轴压缩和拉伸试验，测量了恒定吸力和递减吸力不同应力路径下高岭土的应力应变行为。该模型的预测结果不仅与非饱和土三轴压缩特性吻合较好，而且在吸力恒定和吸力减小条件下的三轴拉伸特性中，都可能导致不可恢复的体积压缩(坍塌)。
ABSTRACT A three-dimensional elasto-plastic model for unsaturated soil is presented, using a transformed stress tensor based on the Extended SMP criterion. The influences of suction on the mechanical behavior of unsaturated soil are taken into account in the model by using a parameter named suction stress σ0(s), which is added to net stress to form an effective stress, and associating a yield stress and model parameters with it. The proposed model needs few material parameters, which can be easily determined from the results of ordinary tests, for example, oedometer and direct shear tests or triaxial test. It can predict the stress-strain-strength behavior of unsaturated soil under the conditions of three-dimensional stresses and constant or variable suction. A considerable number of triaxial compression and extension tests on unsaturated compacted kaolin were performed by using a suction-controlled triaxial apparatus, to measure the stress-strain behavior under different stress paths with constant and decreasing suction. The prediction of the proposed model shows good agreement with the measured behavior of unsaturated soil not only in triaxial compression but also in triaxial extension under the conditions of constant suction and reduction in suction, which may induce an irrecoverable volumetric compression (collapse).