关键词: K-G模型, K-G-D模型, 非线性弹性模型, 剪缩模量, 应力路径, 黏性土

Abstract: In order to solve the problem of reckoning without shear contraction in K-G model suggested by Specification of Soil Test and keep its simplicity, a shear contraction modulus is proposed and a three-modulus modified K-G-D model is suggested which has seven parameters; the integrated incremental stress-strain relations are expressed by mean normal stress, generalized shear stress, volumetric strain and generalized shear strain are given. Model calibration for normal consolidated clay soil is carried out by isotropic consolidation tests and drained triaxial compression tests that the mean normal stress remains constant, model verification is carried out by the drained conventional triaxial compression tests, the computation results by the model parameters coincide well with curves of the tests, which demonstrates that the modified method is rational and applicable. The modified model is capable of reflecting the characteristics of pressure sensitivity, shear contraction and strain hardening, and suitable to underconsolidated and normally consolidated clay soils, loose and medium sands under the stress paths of mean normal stress increasing or remaining constant. In addition, the model calibration does not need additional tests, the modified model is clear in concept, simple in form and convenient to use.

Key words: K-G model, K-G-D model, nonlinear elastic model, shear contraction modulus, stress path, clay soils