Generalization of Elastoplastic Model Using p and q for Geomaterials Based on the SMP Criterion

1.岩土材料三维应力弹塑性模型。为了将三维准则--扩展SMP准则应用于粘-摩材料的弹塑性模型，提出了一种基于该准则的转换应力，该转换应力是在转换主应力空间中使准则成为一个以轴为空间对角线的圆锥体而确定的。在此基础上，提出了一种考虑岩土材料三个特性的弹塑性模型。一是岩土材料在三维应力作用下的强度和变形特性;二是岩土材料的塑性特性;三是岩土材料的强度和变形对围压的依赖性。该模型能够预测粘性-摩擦型材料和颗粒材料等岩土材料在三维应力和大范围的应力-应变关系 ...更多信息 在澄清压力下。该模型在堆石坝数值分析中的应用。为了将该模型应用于实际工程，推导了弹塑性本构张量。以某既有堆石坝为例，验证了该模型在土石坝有限元分析中的有效性。计算结果与实测结果吻合较好.非饱和土的三维弹塑性模型。采用基于扩展SMP准则的转换应力张量，建立了非饱和土的弹塑性本构模型。该模型考虑了吸力对非饱和土力学特性的影响，引入吸力应力作为有效应力，并将屈服应力与模型参数相关联，所需材料参数较少，可由常规试验结果确定，如：固结仪和直接剪切试验或双轴试验。该模型可以预测非饱和土在三向应力、常吸力和变吸力条件下的应力-应变-强度特性。利用可控吸力三轴仪对非饱和压实粘土进行了大量的三轴压缩和拉伸试验，测定了不同应力路径下的应力-应变特性。该模型的预测结果与实测结果吻合较好，不仅在三轴压缩条件下，而且在三轴拉伸条件下，在吸力不变和吸力减小的条件下，均能反映出非饱和土的不可恢复的体积压缩（坍塌）特性。少

1. An elastoplastic model for geomaterials in three-dimensional stresses. For applying a three-dimensional criterion the Extended SMP criterion to elastoplastic models for cohesive-frictional materials, a transformed stress based on the criterion is proposed, which is determined by making the criterion become a cone having the axis as the space diagonal in the transformed principal stress space. Furthermore, an elastoplastic model for geomaterials is presented, which takes the following three characteristics of goematerials into consideration. The first is the strength and deformation characteristics of geomaterials in three-dimensional stress; the second is the dilatancy characteristics of geomaterials; the third is the confining-pressure dependency of strength and deformation. The proposed model is capable of predicting the stress versus strain relations of geomaterials including cohesive-factional materials and granular materials in three-dimensional stress and a wide range of the c … More onfining pressure.2. Application of the proposed model to numerical analysis of rock-fill dam. In order to apply the model to practical engineering by using FEM, the elastoplastic constitutive tensor is derived. An example of the existing rock-fill dam was selected to demonstrate the usefiilness of the model in the finite element analysis for predicting deformation of geomaterials under embankment loading. The settlement and the lateral displacement of foundation computed by the proposed model fairly agree with the observed results.3. A three-dimensional elasto-plastic model for unsaturated soil. Using a transformed stress tensor based on the Extended SMP criterion, an elasto-plastic model was proposed for unsaturated soil. The influences of suction on the mechanical behavior ofunsaturated soil are taken into account in the model by using a parameter named as suction stress, 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 the ordinary tests, for example, oedometer and direct shear tests or biaxial 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 clay were performed by using a suction controllable triaxial apparatus, to measure the stress-strain behavior under different stress paths with constant and decreasing suction. The prediction by 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). Less